Research Article
Print
Research Article
A phylogeny of species near Agrostis supporting the recognition of two new genera, Agrostula and Alpagrostis (Poaceae, Pooideae, Agrostidinae) from Europe
expand article infoPaul M. Peterson, Steven P. Sylvester§, Konstantin Romaschenko, Robert J. Soreng, Patricia Barberá|, Alejandro Quintanar, Carlos Aedo
‡ Smithsonian Institution, Washington DC, United States of America
§ Nanjing Forestry University, Nanjing, China
| Missouri Botanical Garden, St. Louis, United States of America
¶ Real Jardín Botánico, Madrid, Spain
Open Access

Abstract

Based on a molecular DNA phylogeny of three plastid (rpl32-trnK, rps16 intron, and rps16-trnK) and nuclear ITS regions investigating 32 species of Agrostidinae, we describe two new genera, Agrostula gen. nov. with a single species and Alpagrostis gen. nov. with four species; provide support for five species in a monophyletic Podagrostis; and include a small sample of 12 species of a monophyletic Agrostis s.s. (including the type and most species of Neoschischkinia), that separates into two clades corresponding to A. subg. Agrostis and A. subg. Vilfa. Agrostula differs from Agrostis in having leaf blades with pillars of sclerenchyma which are continuous between the adaxial and abaxial surface of the blades, dorsally rounded glumes with blunt to truncate and erose to denticulate apices, florets ½ the length of the glumes, lemmas equally wide as long, widest at (or near) apex, apices broadly truncate, irregularly 5 to 7 denticulate to erose, awnless, anthers longer than the lemmas, and rugose-papillose caryopses. Alpagrostis differs from Agrostis in having geniculate basally inserted awns and truncate lemma apices with lateral veins prolonged from the apex in (2)4 setae. The following eight new combinations are made: Agrostula truncatula, Agrostula truncatula subsp. durieui, Alpagrostis alpina, Alpagrostis alpina var. flavescens, Alpagrostis barceloi, Alpagrostis setacea, Alpagrostis setacea var. flava, and Alpagrostis schleicheri. In addition, we provide a key separating Agrostula and Alpagrostis from Agrostis s.s. and other genera previously considered as synonyms of Agrostis; lectotypify Agrostis alpina Scop., A. schleicheri Jord. & Verl., A. truncatula Parl., and A. truncatula var. durieui Henriq.; and neotypify A. setacea Curtis.

Resumen

Sobre la base de una filogenia molecular de ADN de tres regiones plastidiales (rpl32-trnK, rps16 intrón y rps16-trnK) e ITS nuclear de 32 especies de Agrostidinae, describimos dos nuevos géneros, Agrostula gen. nov. con una sola especie, y Alpagrostis gen. nov. con cuatro especies; mostramos el apoyo para las cinco especies dentro de Podagrostis monofilético; e incluimos una pequeña muestra de 12 especies de Agrostis s.s (que incluye el tipo y la mayoría de las especies de Neoschischkinia), este último dividido en dos subclados que corresponden a A. subg. Agrostis y A. subg. Vilfa. Agrostula se diferencia de otras especies de Agrostis por tener láminas foliares con haces de esclerénquima continuos entre las superficies adaxial y abaxial de los limbos, glumas de dorso redondeado y ápice embotado a truncado y eroso a denticulado, antecios de ½ de la longitud de las glumas, lemas tan anchas como largas, lo más ancho en o cerca del ápice, ápices anchamente truncados, irregularmente 5 a 7 denticulados o erosos, sin arista, anteras más largas que los lemas y cariopsis rugosa-papilosa. Alpagrostis se diferencia de otras especies de Agrostis por tener aristas geniculadas insertas basalmente y ápices de lema truncados con venas laterales que se prolongan en (2)4 arístulas apicales. Presentamos las siguientes ocho nuevas combinaciones: Agrostula truncatula, Agrostula truncatula subsp. durieui, Alpagrostis alpina, Alpagrostis alpina var. flavescens, Alpagrostis barceloi, Alpagrostis setacea, Alpagrostis setacea var. flava y Alpagrostis schleicheri. Además, proporcionamos una clave que separa Agrostula y Alpagrostis de Agrostis s.s. y otros géneros previamente considerados como sinónimos de Agrostis, lectotipificamos Agrostis alpina Scop., A. schleicheri Jord. & Verl., A. truncatula Parl. y A. truncatula var. durieui Henriq. y neotipificamos A. setacea Curtis.

Keywords

Agrostis, Agrostula, Alpagrostis, classification, ITS, Neoschischkinia, plastid DNA sequences, phylogeny, Podagrostis, taxonomy

Introduction

The genus Agrostis L. includes ca. 224 species worldwide and is placed in subtribe Agrostidinae Fr., supersubtribe Agrostidodinae Soreng, tribe Poeae R.Br., and supertribe Poodae L. Liu in subfamily Pooideae Benth. (Soreng et al. 2017). The length of the palea was recognized by Trinius (1820, 1824) as an important character in separating species of Agrostis into two groups, those with short paleas in A. sect. Trichodium (Michx.) Trin. and those with longer paleas in A. sect. Vilfa (Adans.) Roem. & Schult. The term “Trichodium net”, based on observations of the Swedish scientist T. Vestergren, to describe the lemma epidermis of Agrostis which bear a fine-meshed network when observed under high magnification, is found almost exclusively in those species with short paleas (Björkman 1960).

A detailed review of the infrageneric classification of the Agrostis was given by Björkman (1960) and later summarized in Widén (1971), Romero García et al. (1988a), and Saarela et al. (2017). In the former Soviet Union, Tzvelev (1976, 1983) recognized four sections in the genus: Agrostis sect. Agrostis (now = A. sect. Vilfa s.s. due to type conservation of Agrostis) containing species with long paleas 1/2–2/3 the length of an usually unawned lemma; A. sect. Pentatherum (Nabel.) Tzvelev with long paleas 2/3–1 the length of a dorsally awned lemma; A. sect. Agraulus (P. Beauv.) Tzvelev with short paleas <1/3 the length of a dorsally awned lemma, and; A. sect. Trichodium (Michx.) Dumort. with paleas absent or short <1/6 the length of a usually unawned lemma. Romero García et al. (1988a, b) in the Iberian Peninsula divided Agrostis into two subgenera: A. subg. Zingrostis A.T. Romero García, G. Blanca López & C. Morales Torres containing species that have diffuse panicles with widely spreading, capillary and divaricate branches, and paleas 1/2–1 the length of an unawned lemma; and A. subg. Agrostis consisting of three sections, A. sect. Agrostis [= A. sect. Trichodium, A. sect. Agraulus (P. Beauv.) Tzvelev] with paleas <1/3 the length of the lemma; A. sect. Vilfa with paleas 1/2–2/3 the length of a usually unawned lemma; and A. sect. Aperopsis Asch. & Graeb. [= Neoschischkinia Tzvelev] with paleas <1/6 the length of the awned or unawned lemma, and an annual lifecycle.

Podagrostis (Griseb.) Scribn. & Merr. was initially described as a section of Agrostis (Grisebach 1852) and was recently updated and revised by Sylvester et al. (2019a, b, 2020) to include ten species native to the western hemisphere. Five additional species of Agrostis were transferred into Podagrostis in Sylvester et al. (2020) of which P. bacillata (Hack.) Sylvester & Soreng and P. rosei (Scribn. & Merr.) Sylvester & Soreng are newly included in our molecular analysis using nuclear internal transcribed spacer (ITS) and three plastid DNA (rpl32-trnK, rps16 intron, and rps16-trnK) markers. Previously, P. thurberiana (Hitchc.) Hultén was included in a phylogenetic study based on morphology and three plastid regions, and the taxon was weakly supported as the sister group of a strongly supported Agrostis + Polypogon Desf. clade (Soreng et al. 2007). A limitation of that analysis was that only a single species was included for each of the three genera. No molecular study has included more than two species to test the monophyly of this putative lineage (Saarela et al. 2017). The salient characters separating Podagrostis from Agrostis are: a) floret usually equaling or subequaling the glumes, sometimes slightly shorter but reaching past ¾ the length of the glumes, b) palea well-developed, usually reaching from (2/3) ¾ to almost the apex of the lemma, c) presence of a glabrous or distally hairy rachilla extension emerging from under the base of the palea as a slender short stub up to 1.4 mm long (rudimentary in most florets of P. rosei), and d) lemmas unawned or with a short straight mucro 0.2–0.6 mm long, inserted medially or in the upper half of the lemma, not surpassing the glumes (awn 1.6–2 mm long, inserted in lower 1/3 of lemma, straight or geniculate and usually not surpassing glumes in P. rosei) [Sylvester et al. 2020].

Sáez and Rosselló (2000) described Agrostis barceloi L. Sáez & Rosselló from the northern mountains of Mallorca (Balearic Islands) placing it in the Agrostis alpina Scop. complex along with A. curtisii Kerguélen and A. schleicheri Jord. & Verl. These four species share the following synapomorphies: geniculate basally inserted awns and truncate lemma apices that bare lateral setae (extension of the lateral veins) [Romero García et al. 1988a, b; Sáez and Rosselló 2000]. Other species of Agrostis with truncate lemma apices include: A. nebulosa Boiss. & Reut. [= Neoschischkinia nebulosa (Boiss. & Reut.) Tzvelev], A. reuteri Boiss., A. truncatula Parl. (these three placed in A. subg. Zingrostis), A. pourretii Willd. (placed in A. sect. Aperopsis), and A. tenerrima Trin. (placed in A. sect. Agrostis) [Romero García et al. 1988a, b].

Neoschischkinia Tzvelev (1968) initially included two species [N. elegans (Thore) Tzvelev = Agrostis tenerrima Trin., and N. nebulosa (Boiss. & Reut.) Tzvelev = Agrostis nebulosa Boiss. & Reut.] characterized by having diffuse, open panicles with divaricate and capillary branches, trapezoid lemmas with truncate apices, and caryopses with transverse furrows (Tzvelev 1968). Valdés and Scholz (2006) transferred three more species into Neoschischkinia [N. reuteri (Boiss.) Valdés & H. Scholz = A. reuteri, N. truncatula (Parl.) Valdés & H. Scholz = A. truncatula, and N. pourretii (Willd.) Valdés & H. Scholz = A. pourretii].

The main goals of this study were to estimate the phylogenetic relationships of species near or sister to Agrostis based on ITS and three plastid DNA regions (rpl32-trnK, rps16 intron, and rps16-trnK) for species of Agrostidinae and provide names for two clades that align near but not within Agrostis s.s. In addition, we provide a key separating Agrostula, gen. nov., and Alpagrostis, gen. nov., from Agrostis s.s. and other genera considered as synonyms of Agrostis. We propose lectotypes for Agrostis alpina, A. schleicheri, A. truncatula and A. truncatula var. durieui Henriq., and a neotype for A. setacea.

Material and methods

Phylogenetic analyses

Detailed methods for DNA extraction, amplification, and sequencing are given in Romaschenko et al. (2012) and Peterson et al. (2014, 2015a, b, 2016). We used Geneious Prime 2020 (Kearse et al. 2012) for contig assembly of bidirectional sequences of rpl32-trnL, rps16 intron, rps16-trnK, and ITS regions, and Muscle (Edgar 2004) to align consensus sequences and adjust the final alignment. We identified models of molecular evolution for the cpDNA and nrDNA regions using jModeltest (Posada 2008) and applied maximum-likelihood (ML) and Bayesian searches to infer overall phylogeny. The combined data sets were partitioned in accordance with the number of markers used. Nucleotide substitution models selected by Akaike’s Information Criterion, as implemented in jModelTest v.0.1.1, were specified for each partition (Table 1). The ML analysis was conducted with GARLI 0.951 (Zwickl 2006). The ML bootstrap analysis used 1000 replicates with 10 random addition sequences per replicate. The tree file from the ML result was read into PAUP where the majority-rule consensus tree was constructed. Bayesian posterior probabilities (PP) were estimated using a parallel version of the MrBayes v3.2.7 (Huelsenbeck and Ronquist 2001; Ronquist and Huelsenbeck 2003) where the run of eight Markov chain Monte Carlo iterations was split between an equal number of processors. Bayesian analysis was initiated with random starting trees and was initially run for four million generations, sampling once per 100 generations. The analysis was run until the value of the standard deviation of split sequences dropped below 0.01 and the potential scale reduction factor was close to or equal to 1.0. The fraction of the sampled values discarded as burn in was set at 0.25.

Table 1.

Taxon voucher (collector, number, and where the specimen is housed), country of origin, and GenBank accession for DNA sequences of rps16-trnK, rps16 intron, rpl32-trnL, and ITS regions; a dash (–) indicates missing data.

Taxa Voucher Country rps16-trnK rps16 intron rpl32-trnL ITS
1 Agrostis alpina Scop. [= Alpagrostis alpina (Scop.) P.M. Peterson, Romasch., Soreng & Sylvester] Soreng 7484, Gillespie & Peterson (US) Austria, Niederosterrich MT410018 MT409931 MT396529
2 Agrostis bacillata Hack. [= Podagrostis bacillata (Hack.) Sylvester & Soreng] Evans 145, Lellinger & Bowers (US) Costa Rica, San Jose MT410019 MT409978 MT409932 MT396530
3 Agrostis balansae (Boiss.) Tzvelev Soreng 8967b & Cabi (US) Turkey, Erzurum MT410020 MT409979 MT409933 MT396531
4 Agrostis canina L. Herrero 1874, Aedo, Aizpuru, Alarcón, Aldasoro, Castroviejo, Conti, Estébanez, Güemes, Guillén, Navarro, Pedrol, Prunell, Rico, Rodríguez Gracia & Tinti (MA) Italy, Abruzzo MT410021 MT409980 MT409934 MT396532
5 Agrostis capillaris L. Aedo 19209 (MA) France, Landes MT410022 MT409981 MT409935 MT396533
6 Agrostis curtisii Kerguélen [= Alpagrostis setacea (Poir.) P.M. Peterson, Romasch., Soreng & Sylvester] Gil s.n. (MA) Spain, Coruña MT410023 MT409982 MT409936 MT396534
7 Agrostis curtisii Kerguélen [= Alpagrostis setacea (Poir.) P.M. Peterson, Romasch., Soreng & Sylvester] Louzan s.n. & Rodríguez-Oubiña (MA) Spain, Coruña MT410024 MT409983 MT409937 MT396535
8 Agrostis mertensii Trin. Smith 1288 (US) Sweden, Härjedalen MT410025 MT409984 MT409938 MT396536
9 Agrostis micrantha Steud. Tibet-MacArthur 1516, Wen, Nie, Soreng, Rankin, Yue, Wang & Yue (US) China, Yunnan MT410026 MT409985 MT409939 MT396537
10 Agrostis nebulosa Boiss. & Reut. Serra 8114 (US) Spain MT410027 MT409986 MT409940 MT396538
11 Agrostis nervosa Nees ex Trin. Soreng 5276, Peterson & Sun Hang (US) China, Yunnan MT410028 MT409987 MT409941 MT396539
12 Agrostis pourretii Willd. Carrera s.n. (MA) Spain MT410029 MT409988 MT409942 MT396540
13 Agrostis reuteri Boiss. Escobar-García s.n. (MA) Spain MT410030 MT409989 MT409943 MT396541
14 Agrostis rosei Scribn. & Merr. [= Podagrostis rosei (Scribn. & Merr.) Sylvester & Soreng] Peterson 19053 & Sánchez Alvarado (US) Mexico, Durango MT410031 MT409990 MT409944 MT396542
15 Agrostis schleicheri Jord. & Verl. [= Alpagrostis schleicheri (Jord. & Verl.) P.M. Peterson, Romasch., Soreng & Sylvester] Arán 5627, Patino & Valencia (MA) Spain, Cantabria MT410032 MT409991 MT409945 MT396543
16 Agrostis subpatens Hitchc. Lathrop 5571 (US) Costa Rica MT410033 MT409992 MT409946 MT396544
17 Agrostis trachyphylla Pilg. Peterson 24374, Soreng & Romaschenko (US) Tanzania, Kilimanjaro MT410034 MT409993 MT409947 MT396545
18 Agrostis truncatula Parl. [= Agrostula truncatula (Parl.) P.M. Peterson, Romasch., Soreng & Sylvester] Barberá 916 (MA) Spain MT410035 MT409994 MT409948 MT396546
19 Agrostis truncatula Parl. [= Agrostula truncatula (Parl.) P.M. Peterson, Romasch., Soreng & Sylvester] García Río (MA) Spain, Ciudad Real MT410036 MT409995 MT409949 MT396547
20 Agrostis truncatula Parl. [= Agrostula truncatula (Parl.) P.M. Peterson, Romasch., Soreng & Sylvester] Morales 2470 (MA) Spain MT410037 MT409996 MT409950 MT396548
21 Calamagrostis canescens (Weber ex F.H. Wigg.) Roth Barta 1999-14 (MA) Austria, Niederösterreich MT410038 MT409997 MT409951 MT396549
22 Calamagrostis crassiglumis Thurb. Howell 23214 (US) USA MT410039 MT409998 MT409952 MT396550
23 Calamagrostis epigeios (L.) Roth Calvo 4970 (MA) Czech Republic, South Bohemian MT410040 MT409999 MT409953 MT396551
24 Calamagrostis lahulensis G. Singh Tibet-MacArthur 1317 (US) China MT410041 MT410000 MT409954 MT396552
25 Calamagrostis macrolepis Litv. Soreng 7637, Johnson, Shuvalov, Chapurin, Samsaliev & Samsaliev (US) Kyrgyzstan, Naryn MT410042 MT410001 MT409955 MT396553
26 Calamagrostis pseudophragmites (Haller fil.) Koeler Cabezas 688, Aedo, Calvo, Castroviejo, Constantidinis, Gonzalo, Güemes, Herrero, Karidas, Medina, Navarro, Pedrol, Prunell, Quintanar, Rico & Rodríguez Gracia (MA) Greece, Epiro MT410043 MT410002 MT409956 MT396554
27 Calamagrostis stricta (Timm) Koeler Soreng 7722, Johnson, Shuvalov, Chapurin, Samsaliev & Samsaliev (US) Kyrgyzstan, Chu MT410044 MT410003 MT409957 MT396555
28 Chascolytrum rufum J. Presl Butzke 11180 (US) Brazil MT409958 MT396556
29 Chascolytrum rufum J. Presl Wasum 1178 (US) Brazil, Rio Grande do Sul MT409959 MT396557
30 Chascolytrum subaristatum (Lam.) Desv. Hale 20420 & Soderstrom (US) Mexico, Chiapas MT410045 MT410004 MT409960 MT396558
31 Echinopogon caespitosus C.E. Hubb. Craven 672 (NSW) Australia, New South Wales MT410046 MT410005 MT409961 MT396559
32 Gastridium phleoides (Nees & Meyen) C.E. Hubb. Thomas 9650 (US) USA MT410048 MT410007 MT409963 MT396561
33 Gastridium phleoides (Nees & Meyen) C.E. Hubb. Chase A. 5727 (US) USA MT410047 MT410006 MT409962 MT396560
34 Gastridium phleoides (Nees & Meyen) C.E. Hubb. Gander 8198 (US) USA MT410049 MT410008 MT409964 MT396562
35 Gastridium ventricosum (Gouan) Schinz & Thell. Wood 14625 (US) USA Hawaii, Kaua`i MT410050 MT410009 MT409965 MT396563
36 Podagrostis aequivalvis (Trin.) Scribn. & Merr. Eastham 10895 (US) Canada, British Columbia MT409966 MT396564
37 Podagrostis aequivalvis (Trin.) Scribn. & Merr. Spellenberg 1574 & Spellenberg (US) Canada, Alberni-Clayoquot MT409967 MT396565
38 Podagrostis humilis (Vasey) Björkman Harrison 10038 (US) USA, Utah MT409968 MT396566
39 Podagrostis humilis (Vasey) Björkman Nielsen 6612 (US) USA, Utah MT409969 MT396567
40 Podagrostis thurberiana (Hitchc.) Hultén Crampton 3860 (US) USA, California MT396568
41 Podagrostis thurberiana (Hitchc.) Hultén Davis 2949 (US) USA, Idaho MT410051 MT410010 MT409970 MT396569
42 Podagrostis thurberiana (Hitchc.) Hultén Peterson 19755, Saarela & Sears (US) USA, California MT410052 MT410011 MT409971 MT396570
43 Podagrostis thurberiana (Hitchc.) Hultén Soreng 7419 & Soreng (US) USA, California MT410053 MT410012 MT409972 MT396571
44 Podagrostis thurberiana (Hitchc.) Hultén Terrell 4204 (US) USA, California MT410054 MT410013 MT409973 MT396572
45 Triplachne nitens (Guss.) Link Aedo 12786 (MA) Spain, Murcia MT410055 MT410014 MT409974 MT396573
46 Triplachne nitens (Guss.) Link López Jiménez 1241 & García Tapia (MA) Morocco, Nador MT410056 MT410015 MT409975 MT396574
47 Triplachne nitens (Guss.) Link Rivas Martínez, Costa & Regueiro (MA) Spain, Islas Baleares MT410057 MT410016 MT409976 MT396575
48 Triplachne nitens (Guss.) Link Sanz Fábregas s.n. (MA) Spain, Almeria MT410058 MT410017 MT409977 MT396576

It is critically important to include the type species of genera and other higher taxa when doing molecular studies to know you are using the name correctly as intended by the original author. The following species are the types of their respective genera and are included in our analyses: Agrostis canina L. (type conserved), Calamagrostis canescens (Weber) Roth, Chascolytrum subaristatum (Lam.) Desv., Gastridium ventricosum (Gouan) Schinz & Thell., Neoschischkinia elegans (= Agrostis tenerrima), Podagrostis aequivalvis Trin., and Triplachne nitens (Guss.) Link.

Our study was designed to test relationships of three of the four species (A. alpina, A. curtisii, and A. schleicheri) of the Agrostis alpina group, all five species that have been attributed to Neoschischkinia (N. elegans, N. nebulosa, N. pourretii, N. reuteri, and N. truncatula), Podagrostis, Gastridium P. Beauv., Triplachne Link, and representative samples of Agrostis, Calamagrostis Adans., and Chascolytrum Desv. All of these genera have been found in a clade in previous molecular analyses and in our unpublished trees investigating a large number of species in Agrostis, Calamagrostis, Cinnagrostis Griseb., and Koeleria Pers. (Saarela et al. 2017; Barberá et al. 2019a, b; Peterson et al. 2019). Previous analyses of Polypogon found members of the genus nested in a grade within Agrostis and there was incongruence between the plastid and nuclear signals (Saarela et al. 2017; Romaschenko et al. unpubl.). We do not address this question here (i.e., Polypogon is not included in our sampling) since we lack a large sample of species within Agrostis and it is beyond the scope of our study. Echinopogon caespitosus C.E. Hubb. in subtribe Echinopogoninae Soreng was chosen as the outgroup since it lies outside of the Agrostidinae, but inside supersubtribe Agrostidodinae (Soreng et al. 2017; Tkach et al. 2020).

Taxonomy

Herbarium acronyms follow Index Herbariorum (Thiers, continuously updated). In this treatment glabrous means without pubescence (in the sense of slender, relatively soft hairs). Smooth indicates no prickle-hairs with broad bases and/or hooked or pointed apices (i.e., pubescence can occur on a smooth surface, and a rough or scabrous surface can be glabrous). Specimens in the United States National Herbarium (US) and the Real Jardín Botánico Herbarium (MA) were reviewed for this study, in addition to Romero Zarco (1987), Romero García et al. (1988a, b), Sáez and Rosselló (2000), Clayton et al. (2006), Cope and Gray (2009), and Portal (2009) were consulted during preparation of the descriptions. Beyond types (some only seen in images), only material from herbaria where specimens have been checked and verified by the authors are cited. Parts of the generic key were adapted from Sylvester et al. (2020).

Results

Phylogeny

A total of 176 new sequences from 33 species (48 individuals) are reported in GenBank (Table 1). Total aligned characters for individual regions and other parameters are noted in Table 2. The resulting plastid and ITS topologies were inspected for conflicting nodes (see Fig. 1) with ≥ 80% bootstrap support (BS) and/or posterior probabilities (PP) ≥ 0.95. No supported conflict was found so plastid and ITS sequences were combined.

Table 2.

Characteristics of rps16-trnK, rps16 intron, rpl32-trnL, and ITS, and parameters used in Bayesian analyses indicated by Akaike Information Criterion (AIC).

rps16-trnK rps16 intron rpl32-trnL Combined plastid data ITS Overall
Total aligned characters 738 845 904 2487 712 3199
Number of sequences 41 40 47 128 48 176
Likelihood score (-lnL) 1259.16 1449.21 1888.70 1989.55
Number of substitution types 6 6 6 6
Model for among-sites rate variation gamma gamma gamma gamma
Substitution rates
rAC 2.44683 2.33760 1.03926 0.78611
rAG 2.12801 1.84060 0.64852 2.03233
rAT 0.11415 0.31850 0.20833 1.27811
rCG 1.41016 0.78529 0.73967 0.31482
rCT 2.47892 2.54521 0.97480 5.07499
rGT 1.00000 1.00000 1.00000 1.00000
Character state frequencies
fA 0.28602 0.35597 0.36767 0.22141
fC 0.16385 0.15120 0.14893 0.29792
fG 0.16537 0.18750 0.13618 0.29123
fT 0.38477 0.30534 0.34722 0.18944
Proportion of invariable sites 0.37013 0.1041 0.36504 0.30563
Substitution model TVM+G GTR+I+G GTR+G GTR+I+G
Gamma shape parameter (α) 0.90138 0.45913 0.83500 0.38018
Figure 1. 

Maximum-likelihood tree inferred from combined plastid (rpl32-trnL, rps16 intron, rps16-trnK) and ITS sequences. Numbers above the branches are posterior probabilities; numbers below the branches are bootstrap values; accessions marked with an asterisk* were formerly included in Neoschischkinia; and letters refer to clade A = Agrostis subg. Agrostis and clade B = A. subg. Vilfa. Scale bar: 0.002 substitutions per site.

The ML tree from the combined plastid and ITS regions (Fig. 1) is well resolved (posterior probabilities identified in the Bayesian analysis are included on the ML tree, and most clades include a PP = 1), with strong support (BS ≥ 96–100) for the following clades: two species of Gastridium, four accessions of Triplachne nitens, an Agrostis s.s. clade that includes two subclades A and B, three accessions of Agrostis truncatula, and the Agrostis alpinaA. curtisiiA. schleicheri clade; moderate support (BS = 84–86%) for seven species of Calamagrostis and two species of Chascolytrum; and weak support (BS = 57%) for five species of Podagrostis. Chascolytrum is basal followed by, in order of divergence, a clade with Agrostis truncatula sister to Calamagrostis, a clade with Gastridium sister to Triplachne which is sister to the remaining species in the Agrostis s.l. clade (PP = 1, BS = 66). In Agrostis s.l., Podagrostis is sister to the Agrostis alpinaA. curtisiiA. schleicheri clade and the Agrostis s.s. clade.

Discussion

Our molecular sampling of five species of Podagrostis is the largest to date. In an earlier Romaschenko et al. (unpubl.) study of the three species then in the genus, P. humilis (Vasey) Björkman exhibited incongruence with the nuclear ITS signal aligning within the Podagrostis clade and the plastid signal aligning as sister to Agrostis s.s. in a grade with the Agrostis alpinaA. curtisiiA. schleicheri clade at the base. The addition of P. bacillata and P. rosei in our analysis eliminated this anomaly. In an earlier study primarily using different DNA markers with only P. aequivalvis and P. rosei (as Agrostis rosei Scribn. & Merr.), Saarela et al. (2017) found P. rosei to be part of a well-supported clade with four Chinese species of Deyeuxia Clarion ex P. Beauv. and Calamagrostis bolanderi Thurb. + P. aequivalvis. Although C. bolanderi’s placement in a strongly supported lineage with P. aequivalvis provides support for its transfer to Podagrostis, we hesitate to include it here because it may represent a separate hybrid between Podagrostis and Calamagrostis (Sylvester et al. 2020). A robust phylogeny with the inclusion of P. colombiana Sylvester & Soreng, P. exserta (Swallen) Sylvester & Soreng, P. liebmannii (E. Fourn.) Sylvester & Soreng, and P. trichodes (Kunth) Sylvester & Soreng is needed, as well as the Asian species of Deyeuxia that are allied with the group and are in need of generic realignment.

Affinities of Agrostis truncatula are unclear, given the lack of support for its position (PP = 0.52) in the phylogeny sharing a common ancestor with Calamagrostis rather than aligning within Agrostis s.l. Agrostis truncatula has many unique morphological characteristics and differs from other species of Agrostis in having the combination of perennial habit, leaf blades with pillars of sclerenchyma that are continuous between the adaxial and abaxial surface of the blades, dorsally rounded glumes with blunt to truncate and erose to denticulate apices, open and diffuse panicles, florets ½ the length of the glumes, lemmas equally wide as long, widest at (or near) apex, apices broadly truncate, irregularly 5 to 7 denticulate to erose, awnless, anthers longer than the lemmas, and rugose-papillose caryopses. We, thus, describe Agrostula gen. nov. below based on the single species, A. truncatula, with two subspecies. We find no support for recognizing Neoschischkinia (Tzvelev 1968; Valdés and Scholz 2006), since four of the five species attributed to the genus align in the Agrostis s.s. clade: A. nebulosa, A. reuteri, and A. tenerrima (type of Neoschischkinia) in Agrostis subg. Vilfa (clade B), and A. pourretii in A. subg. Agrostis (clade A); whereas A. truncatula is phylogenetically isolated from Agrostis (Agrostula). All these species exhibit unusual characteristics not commonly found within Agrostis, i.e., diffuse, open panicles with divaricate and capillary branches, trapezoid lemmas with truncate apices, and caryopses with transverse furrows. However, without molecular DNA evidence, earlier systematists could not predict the complicated phylogenetic history of Agrostula truncatula.

Our rationale for recognizing the Agrostis alpina complex in a new genus, Alpagrostis gen. nov., is straightforward. Much like Podagrostis, there are salient morphological features, i.e., geniculate basally inserted awns and truncate lemma apices with setaceous lateral veins, and there is strong clade support as sister to Agrostis s.s. The branch length of the Alpagrostis clade is moderately long indicating genetic differentiation shared among its members separating it from other clades. Sáez and Rosselló (2000) suggested that Agrostis barceloi, a tetraploid (2n = 28), is closely related to A. schleicheri, a hexaploid (2n = 42), and might have originated by the splitting of the shared ancestral lineage. The morphological features shared by A. barceloi and A. schleicheri suggest they may be derived from the diploids, A. alpina (2n = 14) or A. curtisii (2n = 14) since the former two species are geographically and genetically isolated (Sáez and Rosselló 2000). Massó et al. (2016) surveyed 40 of the 100 known individuals of the extremely narrow endemic, A. barceloi, for allozyme diversity, showing all loci to be monomorphic or with fixed heterozygosity consistent with allopolyploid origin (interspecific hybridization process and subsequent chromosome duplication) [Stebbins 1947; Crawford 1989; Soltis and Soltis 2000].

The Agrostis s.s. clade is divided into two strongly supported A and B clades that correspond to species that align in the Agrostis subg. Agrostis (clade A) or Agrostis subg. Vilfa (Adans.) Rouy (clade B) [≡ A. sect. Vilfa (Adans.) Roem. & Schult.]. As mentioned in the introduction, palea length is an important character used to separate these two subgenera and all species in clade A have paleas ≤1/3 the length of the lemma as expected, sometimes rudimentary or absent as in e.g. A. mertensii Trin., A. subpatens Hitchc. However, not all species in clade B have paleas ½–2/3 the length of the lemma since A. tenerrima has paleas 1/6 the length of the lemma and only about 0.1 mm long. This is not terribly surprising since hybrids among species of Agrostis are often fertile, and inter-subgeneric hybrids include A. canina × A. stolonifera L., a cross between the type of each subgenus of Agrostis (Widén 1971; Belanger et al. 2003; Watrud et al. 2004). In the future we intend to publish a large phylogeny of Agrostis with a comprehensive species sampling. In this larger paper we will also address the hybrid origins that complicate species relationships in Agrostis s.s. with members of Polypogon, Lachnagrostis Trin., and Chaetotropis Kunth, genera that form a clade sister to or are reticulately intermeshed within Agrostis s.s. (Saarela et al. 2017; Soreng et al. 2017: 268).

Taxonomic treatment

Agrostula P.M. Peterson, Romasch., Soreng & Sylvester, gen. nov.

Type

Agrostis truncatula Parl.

Diagnosis

The one species of Agrostula differs from all other species of Agrostis by its glumes being dorsally rounded, not keeled, smooth throughout, and with apices blunt to truncate and erose to denticulate. Further differentiation can be made by the combination of perennial habit, leaf blades with pillars of sclerenchyma that are continuous between the adaxial and abaxial surface of the blades, panicles open and diffuse, florets ½ the length of the glumes, lemmas equally wide as long, widest at (or near) apex, apices broadly truncate, irregularly 5 to 7 denticulate to erose, awnless, paleas c. ½ the length of the lemma, anthers longer than the lemma, caryopsis surface rugose-papillose, and its ecology, being found growing in very shallow soils.

Description

Perennials moderately to densely tufted. Culms 10–40 cm tall, erect, arching, or geniculate-ascendant, slender, smooth, usually with 3 or 4 nodes extended above the basal foliage. Tillers intravaginal, extravaginal innovations absent. Leaves mostly basal, in fascicles of few to many leaves; sheaths often as long as or sometimes longer than the internodes, glabrous, smooth; ligules 0.5–4 mm long, longer than they are wide in subsp. truncatula and shorter than they are wide in subsp. durieui, oblong, hyaline, glabrous, smooth, apices truncate to acute, dentate; basal and tiller ligules 0.5–2.5 × 1–2.5 mm; upper culm ligules 3–4 × 1–2.5 mm in subsp. truncatula; blades flat, conduplicate, or convolute, straight to sometimes recurved after flowering, acute, firm to rigid, glabrous, abaxially scabrous, adaxially scabrous; blades of lower culm and tillers 3–7 cm long, 0.7–2 mm in diameter as flat, folded or rolled; blades of upper culm 1–4 cm long, 0.5–1.2 mm in diameter as flat, folded or rolled. Inflorescence c. 2–20 × 2–12 cm, a panicle, diffuse and open, broadly ovoid; panicle branches divaricate, capillaceous, with spikelets present only in the distal 1/3–½, glabrous, smooth; pedicels generally twice as long as the spikelets or longer, thickened, apices clavate, glabrous, smooth. Spikelets 1–1.7 mm long, 1-flowered, disarticulating above the glumes, dorsally compressed or very weakly laterally compressed; glumes equal or subequal, ovoid-lanceolate, membranous, 1-veined, the vein inconspicuous, dorsally rounded, smooth throughout, apices truncate to blunt and minutely notched, erose to denticulate; floret c. ½ the length of the glumes, sessile; lemmas 0.5–0.8 mm long in subsp. truncatula and (0.7–)0.9–1(–1.2) mm long in subsp. durieui, broadly ovoid, equally wide as long, widest at (or near) apex, membranous, dorsally rounded, 5-veined, veins usually evident to distinct, with at least the outer veins excurrent, usually glabrous or sometimes pubescent, smooth throughout, apex broadly truncate and denticulate, with the veins terminating in 5 to 7 teeth 1/8–1/5 the length of the lemma, awnless; paleas 0.3–0.5 mm long, c. ½ the length of the lemma, glabrous, smooth, apices bifid, denticulate; calluses rounded, blunt, glabrous or almost so, abaxially smooth; rachilla prolongation absent. Flowers perfect; lodicules 0.1–0.3 mm long, c. ½ as long as the palea, 2 in number, acute; anthers 0.7–1 mm long, 3 in number; ovaries glabrous. Caryopses 0.8–1.1 mm long, generally longer than the lemmas, only partially concealed at maturity, ellipsoid, surface rugose-papillose, ventrally sulcate, sulcus distinct, almost without rostellum; hilum narrowly elliptic c. 1/6–1/3 the length of the caryopsis; endosperm liquid. 2n = 14 + 0–4B (Garde 1951; Björkman 1960; Fernandes and Queiros 1969; Queiros 1974, 1979; Romero García and Blanca López 1988).

Distribution and ecology

Iberian Peninsula and northern Africa, distributed in France, Spain, Portugal, and Morocco. Found in Mediterranean, Iberian-Atlantic and cold temperate, often high-elevation, environments of the Pyrenees. Forms part of pioneer grassland species assemblages which grow on very shallow and sandy ‘skeleton’ soils, apparently reliant on climatic humidity in addition to precipitation for its water supply. Usually flowering from June to July.

Notes

Agrostula truncatula also differs in its leaf blade anatomy from most other species of Agrostis in having pillars of sclerenchyma which are continuous between the adaxial and abaxial surface of the blades. These continuous pillars of sclerenchyma are exceptionally thick and found only on the margins and central vein in subsp. truncatula, while subsp. durieui has thinner continuous sclerenchyma packets in the margins, central and primary veins (Romero García and Blanca López 1988: fig. 4C–F). Costal cells and intercostal long cells of the abaxial blade surface are also distinct, with A. truncatula differing from species of Agrostis in the Iberian Peninsula in having paired s0-z cells in the costal zone, and l3 type long cells in the intercostal zone (Romero García and Blanca López 1988). Stomata are also apparently absent on the abaxial blade surface, a character found in only a few other species in the Iberian Peninsula, i.e., Agrostis reuteri and Alpagrostis setacea (Romero García & Blanca López, 1988).

Agrostula truncatula (Parl.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis truncatula Parl., Fl. Ital. 1: 185. 1848 ≡ Neoschischkinia truncatula (Parl.) Valdés & H. Scholz, Willdenowia 36(2): 663. 2006. Type: Spain, Sierra de Guadarrama, Aug 1841, G. Reuter s.n. (lectotype, designated here: FI-016207 [image!]; isolectotypes, FI-016206 [image!], FI-012389 (Webb herbarium, left hand plant) [image!]).

Agrostula truncatula subsp. durieui (Boiss. & Reut. ex Willk.) P.M. Peterson, Romasch., Quintanar, Soreng & Sylvester, comb. nov.

Agrostis durieui Boiss. & Reut. ex Willk., Suppl. Prodr. Fl. Hisp. 15. 1893 ≡ Agrostis truncatula subsp. durieui (Boiss. & Reut. ex Willk.) Asch. & Graebn., Syn. Mitteleur. Fl. 2(1): 193. 1899 ≡ Agrostis delicatula subsp. durieui (Boiss. & Reut. ex Willk.) Rivas Mart., Lazaroa 2: 328. 1980 ≡ Neoschischkinia truncatula subsp. durieui (Boiss. & Reut. ex Willk.) Valdés and H. Scholz, Willdenowia 36(2): 663. 2006. Type: Spain. Asturias: Peñaflor [“Hab. in Asturiis freq., usque ad summa juga occident., Peñaflor”], 16 Jun 1835, M.C. Durieu de Maisonneuve s.n. [Durieu Plant. Select. Hispano-Lusit sect. 1 Asturicae. Collectae, no. 173] (lectotype, designated by A.T. Romero García and G. Blanca, Taxon 35(4): 695. 1986: P-02219803 [image!]; isolectotypes: P-03487772 [image!], W-18890096450 [image!].

= Agrostis durieui Boiss. & Reut. ex Gand., Bull. Soc. Bot. France 43: 210. 1896, nom. illeg. hom., non Boiss. and Reut. ex Willk. 1893. Type: Spain. Palencia: m. “Peña Labra, in fissuris, rupium cacuminis, 5700 ft, 26 Jul 1894, M. Gandoger s.n.” (lectotype, designated by S. Castroviejo and A. Charpin, Candollea 54(2): 475. 1999: LY [lower specimen]).

= Agrostis truncatula var. durieui Henriq., Bol. Soc. Brot. 20: 49. 1903, nom. Illeg. hom., non subsp. durieui Asch. & Graebn. Type: Spain. Asturias, 27 May 1864, Borgeau 2716. (lectotype, designated here: P-03330466 [image!]; isolectotypes: P-02220227 [image!], P-03330465 [image!], P-03487775 [image!].

= Agrostis truncatula subsp. commista Castrov. & Charpin, Candollea 38(2): 676. 1983, nom. illeg. superfl. Type: Spain. Zamora: Lubián, Chanos, proximidades del puerto de Padornelo, 29T PG 7356, 1200 m, 30 Dec [Jul] 1977, S. Castroviejo 790 (holotype: MA-242072 [image!]; isotype: G-00191448 [image!]).

Notes

Romero García et al. (1988a) provide a key to differentiate the two subspecies. The typical subspecies has ligules as long or longer than wide with acute apices, conduplicate leaf blades that recurve at anthesis, and shorter lemmas 0.5–0.8 mm long whereas Agrostula truncatula subsp. durieui has ligules wider than long with truncate apices, flat, rarely conduplicate leaf blades that do not recurve at anthesis, and longer lemmas (0.7–)0.9–1(–1.2) mm long. Portal (2009) treated subsp. durieui as Agrostis durieui for France, and did not recognize A. truncatula as being in France.

Alpagrostis P.M. Peterson, Romasch., Soreng & Sylvester, gen. nov.

Type

Agrostis alpina Scop.

Diagnosis

The species of Alpagrostis differ from Agrostis by a combination of characters in having plants densely tufted with only intravaginal innovations, leaves mainly basal, basal leaf blades involute and setaceous or filiform, conduplicate and acute, 0.1–1.2 mm in diameter as folded or rolled, ligules longer than they are wide, spikelets generally > 3 mm long, lemma apices truncate with lateral veins prolonged from the apex in 2 (A. setacea) or 4 setae 0.1–0.5 mm long, and, crucially, and lemmas with a well-developed awn, 3–7.4 mm long, inserted basally c. 0.1–0.4 mm from the base of the lemma, conspicuously twisted and geniculate.

Description

Perennials , densely tufted. Culms 4–75 cm tall, erect or slightly geniculate at the base, slender, smooth or scabrous in the upper part, usually with 2–3 nodes extended above the basal foliage. Tillers intravaginal, extravaginal innovations absent. Leaves mostly basal, in fascicles of few to many leaves; sheaths shorter than the internodes, glabrous, smooth or scabrous; ligules 0.4–5 mm long, longer than they are wide, oblong, hyaline, glabrous, smooth, apices truncate, subacute, acute, entire to dentate; basal and tiller ligules 0.4–3 × 0.15–1.3 mm; upper culm ligules 1.7–5 × 0.7–1.5 mm; blades involute and setaceous or filiform and acute, tender to firm, straight to recurved, glabrous, abaxially smooth to scabrous, adaxially scabrous; blades of the lower culms and tillers 2–25 cm long, 0.1–1.2 mm in diameter as folded or rolled; blades of upper culm 1.5–10 cm long, 0.2–1.5 mm in diameter as folded or rolled, generally wider and shorter than tillers. Inflorescence (1.5–)2–15 × 0.5–3.5 cm, a panicle, lax and open to loosely to densely contracted and spikelike; panicle branches erect, ascendant or patent, with spikelets present from the base to only in the distal ½, glabrous, densely scabrous (or smooth in A. barceloi); pedicels as long as the spikelets, cylindrical, apices clavate, glabrous, densely scabrous (or smooth in A. barceloi). Spikelets (2.7 in A. barceloi–)3–5.2(–5.5) mm long, 1-flowered, disarticulating above the glumes, weakly laterally compressed; glumes unequal, the lower shorter and thinner than the upper, upper glume longer than the length of the floret by c. 0.8–1.9 mm, lanceolate, membranous, glabrous, keel scabrous throughout or in the distal ½, lateral veins smooth or scabrous distally, surfaces smooth or scabrous distally, apices acute or mucronate; lower glume 1-veined; upper glume (1-veined in A. barceloi) 3-veined; floret sessile, much shorter than the glumes; lemmas (1.8 in A. barceloi–)2–3.7, lanceolate, membranous, dorsally rounded, 5-veined, veins usually evident to distinct, with at least the outer veins excurrent, glabrous or thinly pubescent at the base with hairs up to 0.4 mm long, surface smooth to densely scabrous with aculeate (thin short stiff) prickles throughout, apex truncate with lateral veins prolonged from the apex in 2 (A. setacea) or 4 setae 0.1–0.5 mm long, awned with awn inserted basally c. 0.1–0.4 mm from the base of the lemma (or sometimes in the lower 1/5–1/4 in A. barceloi), awn well-developed, 3–7.4 mm long, surpassing the glumes, geniculate in roughly the middle, distinctly twisted proximally with usually at least 2 full twists below the bend, smooth proximally, scabrous distally or for most of the length; paleas 0.4–1 mm long, 1/5–1/3 the length of the lemma, glabrous, smooth, apices bifid, dentate, irregularly dentate or emarginate; calluses rounded, blunt, pilose, with hairs 0.3–0.7 mm long inserted all around or in 2 lateral tufts, abaxially smooth; rachilla prolongation absent. Flowers perfect; lodicules 0.4–0.6 mm long, ½–2/3 as long as the palea, 2 in number, acute to lanceolate; anthers 0.7–2.3 mm long, 3 in number; ovaries glabrous. Caryopses 1.7–2 mm long, shorter than the lemmas, concealed at maturity, ellipsoid or fusiform, surface smooth (becoming narrow and shriveled with age), ventrally sulcate, sulcus distinct, almost without rostellum; hilum 1/6–1/3 length of the caryopsis, narrowly elliptic; endosperm liquid. 2n = 14 (In A. setacea, A. alpina), 28 (A. barceloi), or 42 (A. schleicheri) [Frey 1997; Sáez and Rosselló 2000].

Distribution and ecology

Europe and Mediterranean. Found in cold temperate, often high-elevation environments, often found growing on nutrient poor soils. Usually flowering from June to August.

Notes

All caryopses examined from herbarium specimens had a liquid lipid endosperm or were shriveled with a deep sulcus, implying that fresher specimens likely had a liquid endosperm. Agrostis sect. Bromidium (Nees & Meyen) E. Desv. shares many characteristics with Alpagrostis, such as lemma apices terminating in scabrous setae, well-developed, thickened, twisted and geniculate awns inserted in the lower 1/3 of the lemma, palea < 1/3 the length of the lemma, caryopses with liquid to semi-liquid endosperm. Based on molecular DNA studies, Romaschenko et al. (unpubl.) and Tkach et al. (2020) found Bromidium to align within Agrostis s.s.

Alpagrostis barceloi differs somewhat from the other species in the genus, in terms of the panicle branches and pedicels being smooth, spikelets sometimes being shorter, 1-veined upper glumes, and awn sometimes inserted slightly higher up the lemma.

Alpagrostis alpina (Scop.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis alpina Scop., Fl. Carniol. ed. 2, 1: 60. 1772 ≡ Agraulus alpinus (Scop.) P. Beauv., Ess. Agrostogr.: 5. 1812 ≡ Agrestis alpina (Scop.) Bubani, Fl. Pyren. 4: 287. 1901. Type: “Habitat in Alpibus Vochinensibus” and “HALL Hist. n. 1477”, SCHEUCHZ. Gram pag. 140, Prodr. P. 22, tab. 4, fig. 1.”, original material: In siccioribus Alpium Helveticarum & Rhaeticarum pratis, J. Scheuchzer s.n. (lectotype, designated here: W-18890240472 [image!]. fig. 2

Alpagrostis alpina var. flavescens (Honck.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Aira flavescens Honck., Gew.: 212. 1782 ≡ Avena aurata All., Fl. Pedem. 2: 255. 1785, nom. nov. (non Avena flavescens L.) ≡ Agrostis aurata (All.) Suter, Fl. Helv. 1: 61. 1802, nom. superfl. ≡ Agrostis flavescens (Honck.) Host, Icon. Descr. Gram. Austriac. 4: 52. 1809 ≡ Agrostis rupestris var. aurata (All.) Clairv., Man. Herbor. Suisse: 16. 1811 ≡ Avena rupestris var. aurata (All.) Clairv., Man. Herbor. Suisse: 16. 1811 ≡ Trichodium flavescens (Host) Schult., Oestr. Fl., ed. 2, 1: 165. 1814 ≡ Agraulus flavescens (Host) Sweet, Hort. Brit., ed. 2: 556. 1830 ≡ Agrostis alpina var. flavescens (Honck.) Schrad., in Schlechtendal, Linnaea 12: 435. 1838 ≡ Agrostis alpina var. aurata (All.) Ducommun, Taschenb. Schweiz. Bot.: 852. 1869 ≡ Agrostis alpina f. aurata (All.) Beldie, Fl. Reipubl. Popularis Sin. 12: 163. 1972. Type: Switzerland. Bagnes A. Haller hist. 1488 [a description] (lectotype needed).

Alpagrostis barceloi (L. Sáez & Rosselló) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis barceloi L. Saéz & Rosselló, Bot. J. Linn. Soc. 133: 361–365, f. 1. 2000. Type: Spain. Insulae Balearicae [Balearic Islands], Majorca, in praeruptis rupium umbrosis calcareis septentrionalibus loco dicto Puig Major de Son Torrella, 1400 m, 31SDE8206, 14 Aug 1998, L. Sáez 5132 (holotype: BC-852322; isotypes: BCC, M, W-20040000640 [image!], herb. L. Sáez).

Notes

This species is included in Alpagrostis based on its similar morphology, although this needs to be confirmed in molecular analyses. Certain characteristics sometimes differ from the other species in the genus, i.e., spikelets and lemmas sometimes shorter, insertion of the awn sometimes higher on the lemma, panicle branches and pedicels smooth or scaberulous. Alpagrostis barceloi shares with other member of the genus, conduplicate leaf blades, truncate lemma apices with setaceous extensions of the lateral veins, and ecologically is a strict orophyte, much like A. alpina and A. schleicheri (Sáez and Rosselló 2000).

Alpagrostis setacea (Poir.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis setacea Curtis, Pract. Obs. Brit. Grasses ed. 1: 35, no. 4. post (Aug) 1787, nom. illeg. hom. (non Villars (Feb) 1787) ≡ Agrostis setacea Curtis, Fl. Londin. 6, t. 12. 1798 ≡ Agrostis rupestris var. setacea Poir. in Lam., Encycl., Suppl. 1: 247. 1810 ≡ Vilfa setacea (Poir.) P. Beauv., Ess. Agrostogr.: 16. 148. 1812 ≡ Trichodium setaceum (Poir.) Roem. & Schult., Syst. Veg. ed. 15 bis, 2: 280. 1817 ≡ Agraulus setaceus (Poir.) Gray, Nat. Arr. Brit. Pl. 2: 149. 1821 [1822] ≡ Agrestis setacea (Poir.) Bubani, Fl. Pyren. 4: 286. 1901 ≡ Agrostis curtisii Kerguélen, Lejeunia, n.s., 75 (Err. & Corr.): 1. 1975 ≡ Agrostis curtisii Kerguélen, Lejeunia, n.s., 75 (Err. & Corr.): 1. 1975. Type: England. Curtis’s garden [Sowerby’s Herbarium], (neotype, designated here: BM-001144085 [image!]). fig. 3A.

Notes

Philipson (1937) mentions “No authentic specimens of Curtis have been preserved. There is one specimen in the British Museum Herbarium, originally from “Curtis’s garden” (BM-001144085), which may be taken as representative of the species.” Philipson was possibly referring to this specimen. On the neotype there are three different collections on the same sheet. The specimen on the upper left of the sheet is BM-001144085 (Fig. 2A).

Figure 2. 

Alpagrostis alpina A, D spikelets B caryopsis C floret E floret, showing dorsal surface. Plant fragments taken from Sain-Lager 3 (US-1628154).

Alpagrostis setacea var. flava (Des Moul.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis setacea var. flava Des Moul., Actes Soc. Linn. Bordeaux 11: 320. 1840 ≡ Agrostis curtisii var. flava (Des Moul.) Portal, Agrostis de France: 193. 2009. Type: France. Dans les bois découverts, les bruyères et les landes rases, aux environs de Sagonzac (Périgord), 26 May 1838, M.C. Durieu de Maisonneuve #90bis (holotype: not found; isotypes: MPU-027078 [image!], MP-027079 [image!], W-18890240353 [image!], W-18890240354 [image!]).

Alpagrostis schleicheri (Jord. & Verl.) P.M. Peterson, Romasch., Soreng & Sylvester, comb. nov.

Agrostis schleicheri Jord. & Verl., Arch. Fl. France Allemagne 1: 347, 346–348. 1855 ≡ Trichodium schleicheri (Jord. & Verl.) Fourr., Ann. Soc. Linn. Lyon, n.s., 17: 181. 1869 ≡ Agrostis subspicata Arv.-Touv., Essai Pl. Dauphiné: 67. 1871, nom. illeg. superfl. ≡ Agrostis alpina proles schleicheri (Jord. & Verl.) Asch. & Graebn., Syn. Mitteleur. Fl. 2(1): 187. 1899 ≡ Agrestis schleicheri (Jord. & Verl.) Bubani, Fl. Pyren. 4: 288. 1901 ≡ Agrostis alpina subsp. schleicheri (Jord. & Verl.) Rouy, in G. Rouy & J. Foucaud, Fl. France 14: 69. 1913. Type: France. Débris mouvants des rochers calcaries de Mt. St-Nizier près de Grenoble (Isère), 15 Jul 1854, Jean-Baptiste Verlot 1584 (lectotype, designated here: P-03161255 [image!], isolectotypes: BM-001134099 [image!], BM-001134098 [image!], MPU-027081 p.p. Verlot 1584 [image!], MPU-027082 [no image], P-03656627 [image!]).

Notes

Jordon (1855) cited the following five collections: the Jura sur le Reculet (Ain), and Mont Ventoux, in August 1841, A. Jordan; Mt. St-Nizier near Grenoble, Verlot; Bex (canton of Vaud), E. Thomas; Mt. St-Nizier near Grenoble, Clement. Also cited is a report of Reuter of his collection from Jura sur le Reculet [P-03161256, image!], and Agrostis filiformis sensu Vill. We select The Verlot 1584 specimen as there are several duplicates, and P-03161255 as the lectotype because that sheet is not mounted with any other collection as the MPU and BM sheets seem to be.

Figure 3. 

Neotype of Agrostis setacea Curtis [= Alpagrostis setacea (Poir.) P.M. Peterson, Romasch., Soreng & Sylvester] from Curtis’s garden (BM-001144085), upper left hand specimen indicated by A.

Key to differentiate taxa of Agrostula and Alpagrostis from Agrostis and other genera previously considered as synonyms of Agrostis by Watson and Dallwitz (1992) and Clayton and Renvoize (1986)

1 Spikelets disarticulating below the glumes, the glumes, floret, and part of the pedicel falling together as a unit; glume apices lanceolate or lanceolate-subulate, muticous, mucronate or awned; palea < ½ the length of the lemma Polypogon Desf.
Spikelets disarticulating above the glumes, the glumes remaining on the inflorescence after the florets have fallen; glumes acute to acuminate, not awned; palea of varying length, absent or rudimentary to equaling the length of the lemma 2
2 Rachilla extension present (cases where it is sometimes rudimentary key both ways), of varying lengths (sometimes very short, and requiring the base of the palea checked closely to distinguish the structure from hairs), glabrous or pilulose to densely pilose; palea well-developed, generally > 2/3 the length of the lemma 3
Rachilla extension absent; palea of varying length 4
3 Lemmas densely pubescent, with rigid and abundant hairs; callus and rachilla notably hairy; lemmas with a well-developed usually geniculate and twisted awn, > 1 mm long, inserted in the lower or upper half of the lemma, clearly exceeding the glumes; taxa from southern Hemisphere (Australia, Malaysia, New Zealand, South Africa and South America) Lachnagrostis Trin.
Lemmas glabrous; callus and rachilla glabrous or with short hairs emerging from only the rachilla apex and the basal side-ridges of the callus; lemmas unawned or with a short straight awn, usually < 0.5 mm long, inserted in the upper half of the lemma, not or barely exceeding the glumes (awn well-developed, 1.6–2 mm long, inserted in lower 1/3 of lemma, straight or geniculate and usually not surpassing glumes in Podagrostis rosei (Scribn. & Merr.) Sylvester & Soreng, but then callus and rachilla glabrous, rachilla very short, < 0.3 mm long, glabrous, plants from Mexico); taxa from North, Central and South America Podagrostis (Griseb.) Scribn. & Merr. (in part)
4 Lemma apex terminating in 2 or 4 scabrous setae 0.1–2 mm long; lemma with a well-developed geniculate and twisted awn inserted basally or in the lower 1/3 and surpassing the glumes; paleas < 1/3 the length of the lemma; calluses pilulose or densely tufted; leaf blades often filiform or involute; lemma surfaces pilose (Bromidium) or usually glabrous (Alpagrostis); caryopses with liquid endosperm becoming narrow and shriveled with age 5
Lemma apex entire or finely dentate with short teeth at the end of each lateral vein; lemmas muticous, with a straight mucron 0.2–1 mm long, or with a long geniculate and twisted awn to 6+ mm long, inserted in the lower, middle or upper 1/3 of the lemma but usually not basally, not surpassing to greatly surpassing the glumes; lemma surface usually glabrous (sometimes pilose e.g. Agrostis castellana L.); calluses usually glabrous or with hairs restricted to lateral lines continuous with the basal lemma margins; leaf blades of various forms but less often filiform or involute; caryopsis usually rounded, with hardened endosperm, less often with liquid endosperm 6
5 Anthers 0.2–0.7 mm long; lemma surface often pilose; awn inserted in the lower 1/3 but usually not basally; longest setae of lemma apex 0.4–2 mm long; caryopsis thin or with liquid endosperm; leaf blades filiform or flat, generally 1–4 mm diam.; annuals from southern South America Agrostis sect. Bromidium (Nees & Meyen) E. Desv.
Anthers 0.7–2.3 mm long; lemma surface usually glabrous or pilulose basally; longest setae of lemma apex 0.1–0.5 mm long; awn inserted basally; leaf blades filiform or involute, 0.1–1.5 mm diam. as folded or rolled; perennials of Europe and NW Africa Alpagrostis P.M. Peterson, Romasch., Soreng & Sylvester
6 Floret equaling or subequaling the glumes, sometimes slightly shorter but reaching past ¾ the length of the glumes, usually with a short rachilla prolongation emerging behind the palea (sometimes absent in many florets of P. rosei and P. humilis so check many spikelets); paleas well-developed, usually reaching from (2/3) ¾ to almost the apex of the lemma; lemmas muticous or with a short straight awn 0.2–0.6 mm long, inserted medially or in the upper half of the lemma, not surpassing the glumes (awn well-developed, 1.6–2 mm long, inserted in lower 1/3 of lemma, straight or geniculate and usually not surpassing glumes in P. rosei) Podagrostis (Griseb.) Scribn. & Merr. (in part)
Floret notably shorter than the glumes, usually 1/3–3/4 the length of the glumes, rarely longer, without a trace of a rachilla prolongation; paleas well-developed, poorly-developed, or absent, when well-developed reaching from ½–¾ the length of the lemma; lemmas muticous, with a short straight awn 0.2–1 mm long, or with a long geniculate and twisted awn to 6+ mm long, inserted basally, medially or in the upper half of the lemma, not surpassing to greatly surpassing the glumes 7
7 Glumes dorsally rounded, not keeled, smooth throughout, apices blunt to truncate and erose to denticulate; palea c. ½ the length of the lemma; panicles open and diffuse; lemmas equally wide as long, widest at (or near) apex, apices broadly truncate, irregularly 5 to 7 denticulate to erose, awnless; anthers longer than the lemma, caryopsis surface rugose-papillose; perennials; growing from very shallow soils; from the Iberian Peninsula and Northern Africa Agrostula P.M. Peterson, Romasch., Soreng & Sylvester
Glumes keeled, usually scabrous (at least in part), rarely upper glume smooth throughout, apices obtuse to acute-acuminate, rarely blunt to truncate, rounded to muticous; palea absent or rudimentary to ¾ the length of the lemma; panicles open and diffuse to condensed and spikelike; lemmas usually longer than wide (rarely equally wide as long), usually narrowed towards the apex, apices variable, ranging from somewhat broadly to usually narrowly truncate, usually with 2 to 5 dents (sometimes aristulate), to blunt and entire, awnless or with an awn 0.2–6+ mm long; anthers sometimes longer to usually shorter than the lemma; caryopsis surface usually smooth; perennials or annuals; usually growing from well-developed soils, less often from shallow soils, and generally reliant on soil moisture for their water supply; cosmopolitan Agrostis L.

Acknowledgements

We thank Flora iberica project (CGL2014–52787–C3–1–P, CGL2012–32914, CGL201785204-C3-1-P), and FPI fellowship BES-2012-053754 to P. Barberá; the National Geographic Society Committee for Research and Exploration (Grant No. 8848-10, 8087-06) for field and laboratory support; the Smithsonian Institution’s Restricted Endowments Fund, the Scholarly Studies Program, Research Opportunities, Atherton Seidell Foundation, Biodiversity Surveys and Inventories Program, Small Grants Program, the Laboratory of Analytical Biology, and the United States Department of Agriculture. We thank Jeffery M. Saarela, Kanchi N. Gandhi and Francisco Máquez-García for suggesting changes to the manuscript.

References

  • Barberá P, Soreng RJ, Peterson PM, Romaschenko K, Quintanar A, Aedo C (2019a) Molecular phylogenetic analysis resolves Trisetum Pers. (Poaceae: Pooideae: Koeleriinae) polyphyletic: Evidence for a new genus, Sibirotrisetum and resurrection of Acrospelion. Journal of Systematics and Evolution 58(4): 517–526. https://doi.org/10.1111/jse.12523
  • Belanger FC, Meagher TR, Day PR, Plumley K, Meyer WA (2003) Interspecific hybridization between Agrostis stolonifera and related Agrostis species under field conditions. Crop Science 43: 240–246. https://doi.org/10.2135/cropsci2003.0240
  • Björkman SO (1960) Studies in Agrostis and related genera. Symbolae Botanicae Upsalienses 17(1): 1–112.
  • Clayton WD, Renvoize SA (1986) Genera Graminum: Grasses of the World. Kew Bulletin, Additional Series 13: 1–389.
  • Cope T, Gray A (2009) Grasses of the British Isles. BSBI Handbook 13. Botanical Society of the British Isles with Royal Botanic Gardens, Devon, United Kingdom.
  • Edgar RC (2004) MUSCLE: Multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32(5): 1792–1797. https://doi.org/10.1093/nar/gkh340
  • Fernandes A, Queiros M (1969) Contribution á la connaisance cytotaxinomique des Spermatophyta du Portugal 1. Gramineae. Boletim da Sociedade Borteriana, ser 2, 43: 20–140.
  • Frey L (1997) Distribution of Agrostis rupestris and A. alpina (Poaceae) and remarks on their taxonomy and karyology. Fragments Floristica Geobotanica 41: 25–42.
  • Garde A (1951) Breve nota sobre la cariología de algunas Gramíneas Portuguesas. Genetica Iberica 3: 145–154.
  • Grisebach A (1852) Agrostis L. In: Ledebour C (Ed. ) Flora rossica 4(13): 436–442.
  • Jordon CTA (1855) Notice sur plusieurs plantes novelles. Archives de la Flore de France et d’Allemagne 2: 140–448.
  • Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C, Thierer T, Ashton B, Mentjies P, Drummond A (2012) GeneiousBasic: An integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics (Oxford, England) 28(12): 1647–1649. https://doi.org/10.1093/bioinformatics/bts199
  • Massó S, López-Pujol J, López-Alvarado J, Blanché C, Sáez L (2016) One species, one genotype: No genotypic variability in the extremely narrow endemic tetraploid Agrostis barceloi (Gramineae). Plant Systematics and Evolution 302(5): 609–615. https://doi.org/10.1007/s00606-016-1283-9
  • Peterson PM, Romaschenko K, Soreng RJ (2014) A laboratory guide for generating DNA barcodes in grasses: a case study of Leptochloa s.l. (Poaceae: Chloridoideae). Webbia 69(1): 1–12. https://doi.org/10.1080/00837792.2014.927555
  • Peterson PM, Romaschenko K, Herrera Arrieta Y (2015a) A molecular phylogeny and classification of the Eleusininae with a new genus, Micrachne (Poaceae: Chloridoideae: Cynodonteae). Taxon 64(3): 445–467. https://doi.org/10.12705/643.5
  • Peterson PM, Romaschenko K, Herrera Arrieta Y (2015b) Phylogeny and subgeneric classification of Bouteloua with a new species, B. herrera-arrietae (Poaceae: Chloridoideae: Cynodonteae: Boutelouinae). Journal of Systematics and Evolution 53(4): 351–366. https://doi.org/10.1111/jse.12159
  • Peterson PM, Romaschenko K, Herrera Arrieta Y (2016) A molecular phylogeny and classification of the Cynodonteae (Poaceae: Chloridoideae) with four new genera: Orthacanthus, Triplasiella, Tripogonella, and Zaqiqah; three new subtribes: Dactylocteniinae, Orininae, and Zaqiqahinae; and a subgeneric classification of Distichlis. Taxon 65(6): 1263–1287. https://doi.org/10.12705/656.4
  • Portal R (2009) Agrostis de France. (privately published) Imprimerie Jeanne-d’Arc.
  • Queiros M (1974) Contribucao para o conhecimento citotaxonomico das Spermatophyta de Portugal. I, Gramineae.supl.2, Boletim da Sociedade Broteriana, ser 2, 48: 81–98.
  • Queiros M (1979) Números cromosómicos para a flora Portuguesa 16–37. Boletim da Sociedade Broteriana, ser 2, 53: 15–28.
  • Romaschenko K, Peterson PM, Soreng RJ, Garcia-Jacas N, Futorna O, Susanna A (2012) Systematics and evolution of the needle grasses (Poaceae: Pooideae: Stipeae) based on analysis of multiple chloroplast loci, ITS, and lemma micromorphology. Taxon 61(1): 18–44. https://doi.org/10.1002/tax.611002
  • Romero García AT, Blanca López G (1988) Contribución al estudio cariosistemático del género Agrostis L. (Poaceae) en la Península Ibérica. Boletim da Sociedade Broteriana, ser. 2. 61: 81–104.
  • Romero García AT, Blanca López G, Morales Torres C (1988a) Revisión del género Agrostis L. (Poaceae) en la península Ibérica. Ruizia 7: 1–160.
  • Romero García AT, Blanca López G, Morales Torres C (1988b) Relaciones filogenéticas entre las especies ibéricas del género Agrostis L. (Poaceae). Lagascalia 15: 411–415.
  • Romero Zarco C (1987) Agrostis L. In: Valdés B, Talavera S, Fernández-Galiano E (Eds) Flora vascular de Andalucía Occidental 3: 336–441.
  • Saarela JM, Bull RD, Paradis MJ, Ebata SN, Peterson PM, Soreng RJ, Paszko B (2017) Molecular phylogenetics of cool-season grasses in the subtribes Agrostidinae, Anthoxanthinae, Aveninae, Brizinae, Calothecinae, Koeleriinae and Phalaridinae (Poaceae, Pooideae, Poeae, Poeae chloroplast group I). PhytoKeys 87: 1–139. https://doi.org/10.3897/phytokeys.87.12774
  • Soltis PS, Soltis DE (2000) The role of genetic and genomic attributes in the success of polyploids. Proceedings of the National Academy of Sciences of the United States of America 97(13): 7051–7057. https://doi.org/10.1073/pnas.97.13.7051
  • Soreng RJ, Davis JI, Voionmaa MA (2007) A phylogenetic analysis of Poeae sensu lato based on morphological characters and sequence data from three plastid-encoded genes: Evidence for reticulation, and a new classification for the tribe. Kew Bulletin 62: 425–454.
  • Soreng RJ, Peterson PM, Romaschenko K, Davidse G, Teisher JK, Clark LG, Barberá P, Gillespie LJ, Zuloaga FO (2017) A worldwide phylogenetic classification of the Poaceae (Gramineae) II: An update and a comparison of two 2015 classifications. Journal of Systematics and Evolution 55(4): 259–290. https://doi.org/10.1111/jse.12262
  • Sylvester SP, Soreng RJ, Bravo-Pedraza WJ, Cuta-Alarcon LE, Giraldo-Cañas D, Aguilar-Cano J, Peterson PM (2019a) Páramo Calamagrostis s.l. (Poaceae): An updated list and key to the species known or likely to occur in páramos of NW South America and southern Central America including two new species, one new variety, and five new records for Colombia. PhytoKeys 122: 29–78. https://doi.org/10.3897/phytokeys.122.33032
  • Sylvester SP, Soreng RJ, Giraldo-Cañas D (2019b) Podagrostis colombiana sp. nov. (Poaceae): A new genus record and species for Colombia. Kew Bulletin 74: 1–25. https://doi.org/10.1007/s12225-019-9814-5
  • Sylvester SP, Peterson PM, Romaschenko K, Bravo-Pedraza WJ, Cuta-Alarcon LE, Soreng RJ (2020) New combinations and updated descriptions in Podagrostis (Agrostidinae, Poaceae) from the Neotropics and Mexico. PhytoKeys 148: 21–50. https://doi.org/10.3897/phytokeys.148.50042
  • Tkach N, Schneider J, Döring E, Wölk A, Hochbach A, Nissen J, Winterfeld G, Meyer S, Gabriel J, Hoffmann MH, Röser M (2020) Phylogenetic lineages and the role of hybridization as driving force of evolution in grass supertribe Poodae. Taxon 69(2): 234–277. https://doi.org/10.1002/tax.12204
  • Trinius CB (1820) Fundamenta Agrostographiae. J.G. Heubner, Vienna.
  • Trinius CB (1824) De Graminibus Unifloris et Sesquifloris. Impensis Academiae Imperialis Scientiarum, St. Petersburg.
  • Tzvelev NN (1968) Zlaki (Gramineae). Botanicheskii Zhurnal (Moscow & Leningrad) 53: 1–309.
  • Tzvelev NN (1976) Zlaki SSSR [Grasses of the Soviet Union]. Nauka Publishers USSR, Leningrad.
  • Tzvelev NN (1983) Grasses of the Soviet Union [Zlaki SSSR] part 1. Amerind Publishing Co., New Delhi.
  • Watrud LS, Lee EH, Fairbrother A, Burdick C, Reichman JR, Bollman M, Storm M, King G, Van de Water PK (2004) Evidence for landscape-level, pollen-mediated gene flow from genetically modified creeping bentgrass with CP4 EPSPS as a marker. Proceedings of the National Academy of Sciences of the United States of America 101(40): 14533–14538. https://doi.org/10.1073/pnas.0405154101
  • Watson L, Dallwitz MJ (1992) The Grass Genera of the World. CAB International, Wallingford.
  • Widén KG (1971) The genus Agrostis L. in Eastern Fennoscandia. Taxonomy and Distribution. Flora Fennica 5: 1–209.
  • Zwickl DJ (2006) Genetic Algorithm Approaches for the Phylogenetic Analysis of Large Biological Sequence Datasets Under the Maximum Likelihood Criterion. University of Texas, Austin.