Typifications and synonymy in Polystichum (Dryopteridaceae) from Chile and Argentina

Abstract Polystichum Roth is one of the largest and most taxonomically challenging fern genera. South American species have a rich and complex nomenclatural history; many of the early names are inadequately typified. Based on extensive examination of original type material, we designate eleven lectotypes (including Aspidium mohrioides, Aspidium montevidense f. imbricata, Aspidium montevidense f. squamulosa, Aspidium plicatum, Aspidium pycnolepis, Dicksonia andina, Polystichum elegans, Polystichum mohrioides f. latifolia, Polystichum multifidum var. autranii, Polystichum platyphyllum var. kurtziana, and Polypodium polystichoides), and one neotype (Polystichum brongniartianum) for Polystichum taxa. Furthermore, three new synonyms are proposed.

Taxa in the genus Polystichum can be recognized morphologically by stems usually ascending or erect, short internodes, and a dictyostelic stele. Th e monomorphic leaves bear several kinds of scales (hairs are rare); the ultimate segments are mostly asymmetric at base, often acroscopically auriculate, and ordinarily spinulose or at least dentatemucronate at the margins. Th e sori are indusiate or not, when present the indusia are rounded-peltate.
In the course of work on revisions of Polystichum from Argentina and Chile we became aware that critical nomenclatural work with original materials was needed for a number of the taxa. In this manuscript we designate lectotypes for eleven taxa, one neotype, and propose three new synonyms for Central Andean and Southern Andean Polystichum which inhabits Argentina and Chile. We report the novelties for the two regions separately, alphabetically by basionym species name.

Materials and methods
Review of types was based on examination of specimens in herbaria (BA, CONC, CORD, LIL, LP, SGO, SI; acronyms according to Th iers 2013), of digital images provided by source herbaria (B, BM, E, F, GENT, GH, GOET, K, LE, M, MPU, NY, P, S, US, W), or of digital images available via the JSTOR Global Plants portal (http:// plants.jstor.org). All original protologues were reviewed.
Information about botanical publications, authors, dates, collectors and their herbarium and types, were taken from Stafl eu and Cowan (1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988). Th e Melbourne Code (McNeill et al. 2012) was used for the proposed typifi cation. Th e specimens selected as lectotypes are the best-preserved and most complete. Th e lectotype sheets are cited with the barcode number or indicated by the herbarium number, the former are cited with no space between the herbarium acronym and the number, while for accession numbers we have inserted a hyphen between the acronym and the number. Th e lectotype localities correspond to the geographical site mentioned on the specimen itself. If present, additional information (country and fi rst subdivision) about collecting localities is indicated in square brackets. Photographs of the lectotypifi ed specimens that are not available on JSTOR Global Plants are included here.

Taxonomy
Austral-Andean indusiate taxa Th ree specimens are stored at P from Islas Malvinas, two collected by J. S. C. Dumont d´Urville (P00636426 and P00636427) and the third by R. P. Lesson (P00636428). Th e ferns were collected during a circumnavigation in the corvette "Le Coquille" (1822-1825) under the command of Captain L. Duperrey, in which Dumont d'Urville was a second offi cer and Lesson surgeon and naturalist (Duperrey 1828). Probably Dumont-d'Urville described Aspidium mohrioides based on these three specimens but he clearly cited "I. Soledad" as the collection site for the ferns collected in his voyage (Dumont-D´Urville 1825: 26). We designated P00636426 as the lectotype because it is the only one with the locality "I. Soledad", and it is also the most complete sheet, consisting of a fertile plant and two additional fronds. Th e other two specimens comprise two (P00636428) or three (P00636427) mainly juvenile fronds. When Kunze (1834: 94) described Aspidum plicatum, no specimen referable as type was cited. At the same time, he recognized two named varieties (α laxum and β rigidum), citing one type specimen for each variety. According to the International Code of Nomenclature, Arts. 9.5 and 26.2 (McNeill et al. 2012), one lectotype for the species can be selected from the types of either of the two varieties. Th e features given in the protologue for var. rigidum closely match the description of A. plicatum; for this reason, we select one sheet of the type collection of this variety as lectotype (W-0003927!). Among LE's isolectotypes, there are two sheets (LE00008146! and LE00008148!), with incomplete data on their original labels; these labels state: Aspidium plicatum and Aspidium plicatum β respectively, being both Poeppig's gatherings; it is supposed that they are also duplicates.   Rudolph A. Philippi misapplied the name Dicksonia (Fam. Dicksoniaceae), a genus of tree ferns, to specimens of Polystichum. We found three sheets at SGO. Of these, two were collected by his grandson Otto Philippi and the third one by Hirth. Th e original Philippi label of SGO000000513!, indicates "F. Hirth" as the collector name in error, the correct name is "Ad.

Dicksonia andina
[Adolfo] Hirth", as it is written in the protologue. Both accessions of O. Philippi's collection are well preserved. Rodríguez Ríos (1987) unintentionally lectotypifi ed a Philippi´s specimen ("SGO-isosyntypus!"). As in SGO exists two sheets of Philippi, a second step lectotypifi cation is here proposed in accordance to Art. 9.17. Th e selected lectotype (SGO000000511!) is the most complete sheet including one leaf (with intact lamina and petiole). Th e type specimen of P. brongniartianum (C. Gay s. n.) cited by Rémy (1854), is supposed to be housed at P; after a careful search in P, we have found no type material of this name. Neither was any found by other fern taxonomists in other herbaria (Christensen 1910, Looser 1968, Rodríguez Ríos 1987. We propose CONC-13555 as neotype, as it fi ts Rémy's description in its narrowest interpretation. Th ere are three sheets of Gay at P, two sheets are housed as Gay 29 (P00636434! and P00636432!) with data of the collection place, while the third sheet (P00636435!) lacks collector number and only "Chili" is indicated as the collection location. Rod-ríguez Ríos (1987) wrote "Se halla en las altas cordilleras de Talcaregue, provincia de Colchagua, en las orillas de los arroyos, cerca del volcán en donde es algo rara (P!)". Th e Gay 29's collection has a label with the same information cited by Rodríguez Ríos. As a second step lectotypifi cation is necessary, we select P00636434 as the second step lectotype because it includes the diagnostic character for this taxon and it is the most complete accession (three fronds and the petiole scales are intact). We examined the three syntypes of P. mohrioides f. latifolia. All three are of good quality; two are preserved at CORD, and the third at SI. One of the two sheets of Kurtz 11173 (leg. A. Lemos) at CORD is designated as lectotype: CORD 00006865! Hoja A. Th is accession consists of three mature fertile fronds versus Hoja B (isolectotype) with all three sterile leaves. Although there are two sheets of this variety at SI, each indicated as holotype and isotype respectively, it is not possible to be sure that it is from the protologue. Holotype and isotype labels have been added by the SI herbarium staff after Hicken's death. We select as lectotype, SI000112 sheet since it has a label with detailed collection data and consists of two complete fronds.  Christensen (1910) recognized P. multifi dum var. dusenii based on lamina division (twice pinnate-pinnatifi d lamina), and shape and margin of pinnules (pinnules obovate with slightly dentate margins). Looser (1968) suggested that this set of plants should be considered a variety of P. chilense; later, Rodríguez Ríos (1987) agreed and added another diagnostic character (coriaceous pinnules), to support this position and formalized the recognition of the variety: P. chilense var. dusenii (C.Chr.) R.Rodr. We observed frequent variation in the lamina division among P. chilense populations, even within the same population. Th is variability is often associated with the size and age of the plant (Barrington 2012 Th e main diagnostic characters for P. pearcei are the 3-pinnate frond and the rachis slightly scaly (Philippi 1865). Rodríguez Ríos (1987) considered the same diagnostic characters but subordinated this species as a variety under P. multifi dum. Analyzing herbarium specimens and fi eld observations of P. multifi dum, we found high variability in the lamina division and density of scales on the rachis. In addition, when P. multifidum grows in warmer and/or drier conditions, the leaves are smaller, less divided, and not as scaly (Morero, pers. obs.). Since the type of Polystichum pearcei falls within the variation of P. multifi dum, we propose it as a synonym. Molecular studies in progress support this proposal (Barrington pers. comm.). Th is name was based on two syntypes both from Tucumán hills (Argentina): Lorentz 158 and Lorentz & Hieronymus 801. Hieronymus described this taxon with the specimens deposited at B, but a careful search of B does not yield them. Four duplicates of Lorentz 158 exist in herbaria: two housed at CORD, one at US, and a fourth at SI. We select CORD00006873 as the lectotype because it represents an entire plant including a rhizome, fertile fronds with petiole base and rhizome born intact. Characters used to diagnose the species by Condack et al. (2013)-rhizome and petiole scale color, shape, and margin along with the shape and margin of the pinnules-are present in our selected lectotype. We located two of the three syntypes cited by Hieronymus (1897). Both are highquality specimens in agreement with the diagnosis. We have selected Hieronymus 479 at CORD as the lectotype because it is a more complete specimen including all the diagnostic characters for this taxon (the rhizome scales are intact and there are two fronds with fragments of petioles and blades). After a careful analysis of morphological characters of type specimens we have found that their identifying characters (large petiole scales bicolorous with the center atropurpureous and the edge rufous; pinnules coriaceous and revolute with margins serrate and spinules well developed), match fairly the diagnostic characters of P. pycnolepis. Th erefore, we confi rm the synonymy of this form under P. pycnolepis, as proposed by Condack et al. (2013). Kunze ex Klotzsch, Linnaea 20: 365. 1847 Th e type material of Aspidium pycnolepis is a mixed collection. In order to stabilize the application of this name in the sense that it has been used by most other botanists, we choose Moritz 296 b (B200148046!) since most closely represents the original description. Th e remaining syntypes, after the designation of the lectotype of A. pycnolepis, pertain to at least three species, only one of which is P. pycnolepis. We have seen the following: "Columbia, Páramo de la Culata", Th ere are three sheets of Karsten at B (one more, not found, may be housed at LE); from among these, we select B200148238 as the lectotype, because it is a more complete accession containing an entire plant. Based on a careful observation of the three specimens, we consider that all pertain to Polystichum platyphyllum -by the lamina dissection, the shape and color of petiole scales, and the elongate once-pinnate and bulbil-bearing lamina apex-which are diagnostic characters of this taxon. A single collection was cited in the protologue of this varietal name. Of the four duplicates of the type collection, two are housed at CORD, one at NY and the fourth at SI. Th e last one, with a Hicken's handwritten label with the inscription "au var? nova?", was supposedly used by this author for the diagnosis. According to the recommendation of the International Code of Nomenclature (Rec. 9A.3, McNeill et al. 2012), the specimen with an author's annotations on herbarium sheets should be given preference in choosing the lectotype; therefore, SI000116 is designated here as the lectotype.