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PhytoKeys 32: 49–64, doi: 10.3897/phytokeys.32.6733
Toward a monophyletic Cheilanthes: The resurrection and recircumscription of Myriopteris (Pteridaceae)
Amanda Lee Grusz 1, Michael Dennis Windham 1
1 Department of Biology, Duke University, Box 90338, Durham, NC 27708–0338, USA

Corresponding author: Amanda Lee Grusz (alg3@duke.edu)

Academic editor: T. Ranker

received 2 December 2013 | accepted 5 December 2013 | Published 19 December 2013


(C) 2013 Amanda Lee Grusz. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


For reference, use of the paginated PDF or printed version of this article is recommended.

Citation: Grusz AL, Windham MD (2013) Toward a monophyletic Cheilanthes: The resurrection and recircumscription of Myriopteris (Pteridaceae). PhytoKeys 32: 49–64. doi: 10.3897/phytokeys.32.6733

Abstract

The fern genus Cheilanthes (Pteridaceae) has perplexed taxonomists for more than two centuries. Complex patterns of evolution involving rampant morphological convergence, polyploidy, hybridization, and apomixis have made the taxonomy of this group especially difficult. Fortunately, recent phylogenetic analyses have helped to clarify relationships among cheilanthoid taxa. Based on these findings, we here formalize an updated taxonomy for one monophyletic clade comprising 47 primarily North and Central American taxa usually included in Cheilanthes. Because the type species of Cheilanthes (Cheilanthes micropteris) is only distantly related to this clade, we resurrect the genus Myriopteris to accommodate these taxa, and present a revised circumscription for the group, including 36 new combinations.

Keywords

Cheilanthes, cheilanthoid, myriopterid, myriopteroid, nomenclature, taxonomy

Introduction

A “practical and natural” generic classification of cheilanthoid ferns (Pteridaceae) has eluded taxonomists for more than 200 years and was viewed by Tryon and Tryon (1982) as one of the most contentious issues in fern systematics. Central to the problem is the circumscription of the large genus Cheilanthes, which all molecular studies with sufficient sampling indicate is polyphyletic (see Gastony and Rollo 1998; Kirkpatrick 2007; Prado et al. 2007; Schuettpelz et al. 2007; Zhang et al. 2007; Rothfels et al. 2008; Eiserhardt et al. 2011). Since the initial description of Cheilanthes (Swartz 1806) encompassing 16 species, various authors have moved hundreds of taxa into (e.g., Domin 1913; Mickel 1979) and out of (e.g., Fée 1852; Smith 1875; Ching 1941) the genus. Of the ca. 500 validly published species names in Cheilanthes, some 60% have, at some point, resided in other genera. The lack of definitive taxonomic characters in this group often is attributed to widespread convergent evolution in the drought-prone habitats occupied by these ferns (Tryon and Tryon 1973, 1982), and the problem is likely insoluble based on morphology alone. However, the same genetic evidence that highlights shortfalls in the current classification provides a key to solving this puzzle. As DNA sequence data proliferate and morphological features are reexamined in light of molecular phylogenies, it eventually becomes possible to recognize monophyletic assemblages of species that can be circumscribed as genera. We now have reached this point with certain groups of cheilanthoid ferns, at least in terms of removing taxa and clades that cannot reasonably be included within Cheilanthes (Link-Perez et al. 2011; Li et al. 2012).

Here, we focus on the primarily New World lineage previously referred to as the “American Cheilanthes” (Kirkpatrick 2007), myriopteroid (Rothfels et al. 2008), or myriopterid (Windham et al. 2009; Eiserhardt et al. 2011) ferns. Limited sampling in each of those analyses indicated that these ferns might represent a well-supported, monophyletic group, an assumption fully supported by the more complete (85%) taxon sampling of Grusz et al. (in review). In addition to suggesting the monophyly of the myriopterid lineage, the analyses of Rothfels et al. (2008) and Eiserhardt et al. (2011) conclusively demonstrated that this clade was quite distantly related to the type species of Cheilanthes, Cheilanthes micropteris (results summarized in Fig. 1). This improved understanding of phylogenetic relationships among cheilanthoid ferns necessitates a taxonomic revision that can be achieved by one of two options: 1) all taxa derived from the most recent common ancestor of Cheilanthes micropteris and the myriopterid ferns could be assigned to a single genus (which would not be called Cheilanthes because of the priority of Hemionitis), or 2) myriopterid ferns could be transferred to a different genus, reflecting their phylogenetic distinction from Cheilanthes s.s. The first option would require 400+ new combinations in Hemionitis (or the conservation of Cheilanthes against it followed by more than 100 new combinations in that genus). It would also subsume a number of cohesive, well-characterized genera that are clearly distinct based on morphological, molecular, and cytological grounds, including Adiantopsis (Link-Pérez et al. 2011), Argyrochosma (Windham 1987; Sigel et al. 2011), Astrolepis (Beck et al. 2010), Doryopteris (Yesilyurt 2004), Gaga (Li et al. 2012), and Notholaena (Rothfels et al. 2008). This approach would maximize the number of nomenclatural changes while simultaneously obscuring well-documented phylogenetic relationships, resulting in the inclusion of all but six cheilanthoid species in one genus. Because we consider this option untenable, we have, instead, chosen to remove the myriopterid ferns from Cheilanthes.

Figure 1.

Summary phylogeny for cheilanthoid ferns, indicating the placement of Cheilanthes micropteris (the type species for Cheilanthes) within the hemionitid clade—only distantly related to the myriopterid clade. The six major clades of cheilanthoid ferns are shown with tips roughly proportional to clade size. The most recent common ancestor (mrca) of Cheilanthes micropteris and the myriopterid clade is indicated. Modified with permission from Windham et al. (2009).

When any species or clade is removed from Cheilanthes, the first issue that must be addressed involves their relationship to Allosorus pusillus (Willd. ex Bernh.) Bernh. [= Cheilanthes pteridioides (Reich.) C. Chr.]. This species was designated the lectotype of Allosorus Bernh. by Pichi-Sermolli (1953), a choice subsequently validated by the ICBN when Cheilanthes was conserved over Allosorus (Appendix II of the Montreal Code, Stafleu et al. 1961). The only phylogenetic study published to date that includes the type species of both Allosorus and Cheilanthes is that of Eiserhardt et al. (2011). In that analysis, it is unclear whether the divergence between Cheilanthes maderensis (= Cheilanthes pteridioides; see Nardi and Reichstein 1985; Rothfels et al. 2012) and Cheilanthes micropteris is sufficient to justify the recognition of two genera. The two taxa appear in distinct, well-supported clades (clade A vs. clade C in fig. 2B of Eiserhardt et al. 2011), but deeper relationships are poorly resolved and both clearly belong to the rapidly diversifying hemionitid lineage (clade H). The unequivocal assignment of Allosorus to the hemionitids by Eiserhardt et al. (2011) does, however, prevent the application of this generic name to the myriopterid clade. Any attempt to expand Allosorus to include myriopterids would encompass both Cheilanthes (conserved over Allosorus) and Hemionitis (which has priority over both).

One potentially viable option for generic placement of the myriopterid clade would be to include it within a revised circumscription of Pellaea Link. All recent phylogenetic studies with adequate sampling of the two groups (e.g., Kirkpatrick 2007; Rothfels et al. 2008; Eiserhardt et al. 2011) strongly support the position of myriopterids as the sister group of the pellaeid clade, which includes Pellaea atropurpurea, the lectotype of the oldest generic name applicable to that clade. We are not in favor of expanding the definition of Pellaea to encompass the myriopterids for a variety of reasons. First, the two are quite distinct, both in terms of phylogenetic divergence and morphology. The myriopterids have substantially smaller ultimate segments, pubescent and/or scaly (vs. mostly glabrous) leaf blades, and sporangia that are confined to vein tips (vs. distributed along the veins near the segment margins). Because of these differences, the two groups generally have not been considered closely related, and most myriopterids would require new combinations in Pellaea. Adding to this nomenclatural upheaval is the fact that other well-defined genera, including Argyrochosma (Sigel et al. 2011) and Astrolepis (Beck et al. 2010), would be subsumed within such a circumscription of Pellaea, which would require additional new combinations and serve only to further undermine the distinctions among the major genera of cheilanthoid ferns.

If the expansion of Pellaea is ruled out, there remain three other generic names typified by species belonging to the myriopterid clade: 1) Myriopteris, described by Fée (1852) and typified by Myriopteris marsupianthes Fée; 2) Cheilosoria, named by Trevisan (1877) and lectotypified by Copeland (1947) based on Cheilosoria allosuroides (Mett.) Trev.; and 3) Pomataphytum, published by Jones (1930) and typified by Pomataphytum pocillatum M. E. Jones(= Myriopteris lendigera). Phylogenetic reconstructions (Grusz et al. in review) confirm that the type species of Myriopteris and Pomataphytum fall within a single, well-supported clade. In fact, the diploid species Myriopteris marsupianthes is thought to be one of the parents of sexual tetraploid Myriopteris lendigera (see Mickel and Smith 2004). Thus, the generic name Pomataphytum is appropriately considered a taxonomic synonym of the earlier described Myriopteris and can be eliminated as a potential name for the myriopterid clade. Copeland’s (1947) lectotype of Cheilosoria belongs to the well-supported and morphologically distinctive alabamensis clade that diverges earlier in the myriopterid phylogeny (Grusz et al. in review), and the name Cheilosoria could be used for this particular group if the myriopterids were subdivided into two or more genera. However, Myriopteris predates Cheilosoria by 25 years and, when these species are assigned to a single genus (our preferred approach), Myriopteris is the correct generic name for the inclusive myriopterid clade.

Historical use of the name Myriopteris

The original concept of Myriopteris (Fée 1852) included 11 species, these split between two sections (Eumyriopteris and Cheilanthastrum) distinguished by the presence or absence of a well-developed, inframarginal false indusium. The Latin and French descriptions of the genus are only partly overlapping; shared elements include the highly divided fronds, the small, orbicular ultimate segments with recurved margins (“formant un bourrelet très-contracté”), and a tendency to be covered by hairs and/or scales. Myriopteris was accepted and significantly expanded by J. Smith (1875: 280) who stated “the genus consists of about 20 species, distinguished from Notholaena and Cheilanthes by their small, concave, lenticular segments.” The segregation of Myriopteris from Cheilanthes was, however, rejected by most subsequent authors (e.g., Christensen 1906; Copeland 1947; Lellinger 1965; Tryon and Tryon 1982; Kramer et al. 1990), with two notable exceptions. Pichi-Sermolli (1977) advocated a narrowed circumscription of the genus, including only the two species with prominent false indusia, viz., Myriopteris marsupianthes and Myriopteris lendigera. As shown by Grusz et al. (in review), this definition of Myriopteris is phylogenetically indefensible because it excludes Myriopteris mexicana, the apparent maternal progenitor of allotetraploid Myriopteris lendigera. About the same time Pichi-Sermolli was narrowing the definition of Myriopteris, Löve and Löve (1977) expanded it slightly by proposing a new combination for the species known as Cheilanthes covillei Maxon. This was done without explanation, though almost certainly reflects the fact that this species has the small, bead-like ultimate segments emphasized in earlier circumscriptions of the genus.

Although this “microphyllous” leaf morphology is common within Myriopteris, it does not characterize the entire clade (Grusz et al. in review) and has evolved independently in other cheilanthoid lineages. Thus, the possession of small, bead-like ultimate segments does not constitute a synapomorphy for the genus as defined herein. In fact, our list of excluded names (see Taxonomic Treatment) includes seven taxa with bead-like segments previously ascribed to Myriopteris but more closely related to Cheilanthes s.s. (Windham et al. unpublished). Because all morphological characters used by previous authors to define Myriopteris are subject to strong, positive selection in xeric-adapted cheilanthoid lineages (Hevly 1963), it is not surprising that none of them uniquely define the genus. The totality of evidence, however, indicates that the myriopterids represent a deeply divergent clade that cannot reasonably be combined with any other in a single genus. Therefore, we propose to resurrect Myriopteris and recircumscribe it to encompass the entirety of this well supported cheilanthoid lineage.

Distinguishing Myriopteris Fée emend. Grusz & Windham from Cheilanthes s.s.

Ideally, morphological and/or cytological synapomorphies would substantiate phylogenetic relationships inferred from DNA sequence data. However, easily observed synapomorphies distinguishing the various clades of cheilanthoid ferns are few, and homoplastic characters abound. To paraphrase Sir William Hooker (1852: 75), “Vain is the attempt to form a definite character which shall decide the limits of [Cheilanthes], ” a statement that applies equally well to Myriopteris. Highly divided (decompound) leaf blades with small ultimate segments are scattered across the cheilanthoid tree and, indeed, are characteristic of ferns in general, and an indument of hairs and/or scales is one common strategy among plants used to reduce water loss in xeric habitats (Hevly 1963). Other characters useful for species-level identification within myriopterids, such as vernation, are, without exception, shared with other distantly related cheilanthoid ferns.

Molecular analyses spanning the diversity of cheilanthoid species (Windham et al. unpublished) illuminate one particularly useful character distinguishing Myriopteris, as defined herein, from Cheilanthes s.s. The taxa most closely related to the type species of the latter [Cheilanthes micropteris plus all Australian Cheilanthes and a group of South American species including the Cheilanthes scariosa (Sw.) C. Presl complex of Tryon and Tryon (1982), Cheilanthes obducta Mett. ex Kuhn, and Cheilanthes fractifera R. M. Tryon] have 32 small spores per sporangium when sexual, and 16 large spores per sporangium when apomictic. This intriguing cytological synapomorphy results from the elimination of a premeiotic mitosis in the cell lineages generating the sporocytes (Windham et al. unpublished). Aside from a few species of the distantly related genus Notholaena, all other cheilanthoid ferns so far examined (including every Myriopteris species; Grusz et al. in review) produce 64 small spores per sporangium in sexual individuals and 32 large spores per sporangium in apomicts. This character appears to provide an absolute separation between Myriopteris and Cheilanthes s.s., and is easily observed using a dissecting microscope. In combination with differences in spore ornamentation (see Tryon and Lugardon 1991), leaf venation (Pryer et al. 2010), and geographic distribution, this feature provides a clear distinction between the two genera. For diagnostic purposes, then, Myriopteris Fée emend. Grusz & Windham differs from Cheilanthes s.s. (i.e., Cheilanthes micropteris and its close relatives) in its production of 64 small or 32 large (vs. 32 small or 16 large) spores per sporangium; mostly cristate or rugulose (vs. echinate, granulose, or verrucate) spore ornamentation; a lack of obvious vein endings near the margins of the ultimate segments (vs. often prominent hydathodes), and a largely North and Central American (vs. exclusively South American/Old World) distribution.

Taxonomic treatment
Myriopteris Fée emend. Grusz & Windham

http://species-id.net/wiki/Myriopteris

Type.

Myriopteris marsupianthes Fée, Mém. Fam. Foug. 5: 149, t. 12A. f. 1. 1852

Description.

Plants rupestral or terrestrial. Rhizomes compact to long-creeping, ascending or horizontal, scaly. Rhizome scales lanceolate to acicular, concolorous (tan to dark brown) or bicolorous (with dark central stripe and brown margins). Leaf vernation non-circinate to circinate. Petiolescastaneous to black, scaly and/or pubescent, rarely almost glabrous. Rachises terete or flattened or grooved adaxially, with indument similar to that of the petioles. Blades2- to 4-pinnate (rarely pinnate-pinnatifid), lanceolate to ovate-deltate, occasionally linear or pentagonal; adaxial surfaces glabrous or pubescent; abaxial surfaces scaly and/or pubescent or rarely glabrous. Ultimate segments round to oblong-ovate, minute to >1 cm long, the veins obscure and not ending in prominent hydathodes. Segment margins usually recurved, with a poorly differentiated false indusium (strongly differentiated in Myriopteris lendigera and Myriopteris marsupianthes). Sori usually partly to completely covered by the recurved segment margins, the sporangia clustered at vein tips. Sporangia 64-spored (in sexual species) or 32-spored (in apomicts). Spores globose-tetrahedral, tan to brown, cristate to rugulate. Chromosome numbers n = 29, 30, 58, 60 (sexual species); n = 2n = 87, 90 (apomictic triploids); n = 2n = 120 (apomictic tetraploids).

Distribution.

Species of Myriopteris range from southern Canada through the Caribbean and Central America to southern Chile, with one species (Myriopteris rawsonii) endemic to Namibia and South Africa. Mexico is the center of species diversity for the genus; 34 of the 44 species can be found in Mexico, and seven of these are endemic.


New and resurrected combinations in Myriopteris

1) Myriopteris aemula (Maxon) Grusz & Windham, comb. nov. Cheilanthes aemula Maxon, Contr. U.S. Natl. Herb. 10: 495. 1908. Type: Mexico. Tamaulipas: Victoria, in river canyon, under overhanging rocks, altitude about 320 meters, February 1 to April 9, 1907, Palmer 187 (holotype: US; isotype: US). urn:lsid:ipni.org:names:77134841-1


2) Myriopteris alabamensis(Buckley) Grusz & Windham, comb. nov. Pteris alabamensis Buckley, Amer. J. Sci. Arts 45: 177. 1843. Cheilanthes alabamensis (Buckley) Kunze, Linnaea 20: 4. 1847. Type: USA. Alabama: Growing in tufts on limestone rocks that form the banks of the Tennessee River, at the foot of Muscle Shoals, Buckley s.n. (holotype: PH; isotypes: MO, NY). urn:lsid:ipni.org:names:77134842-1


3) Myriopteris allosuroides (Mett.) Grusz & Windham, comb. nov. Cheilanthes allosuroides Mett., Abh. Senckenberg. Naturf. Ges. 3: 78. 1859. Pellaea allosuroides (Mett.) Hieron., Hedwigia 62: 18. 1920. Type: Mexico, Schmitz s.n. (holotype: location unknown). urn:lsid:ipni.org:names:77134843-1


4) Myriopteris aurea (Poir.) Grusz & Windham, comb. nov. Pteris aurea Poir. Encyclopédie Méthodique, Botanique 5: 710. 1804. Type: Peru. Elle a été recueillie au Pérou par Joseph de Jussieu s.n. (sheet 1333 in hb. Jussieu; holotype: P). urn:lsid:ipni.org:names:77134844-1

Acrostichum bonariense Willd., Sp. Pl., ed. 4, 5(1): 114. 1810. Notholaena bonariensis (Willd.) C. Chr., Index Filic. 459. 1906. Cheilanthes bonariensis (Willd.) Proctor, Bull. Inst. Jamaica, Sci. Ser. 5: 15. 1953.

In Cheilanthes, this has been called Cheilanthes bonariensis (Willd.) Proctor because use of the oldest applicable epithet (based on Pteris aurea Poir.) was blocked by the earlier publication of Cheilanthes aurea Baker (Proctor 1953). With the transfer of this species to Myriopteris we revert to the older epithet and thus avoid the typification difficulties associated with the basionym Acrostichum bonariense Willd. (Ponce and Zimmer 2011).


5) Myriopteris chipinquensis (Knobloch & Lellinger) Grusz & Windham, comb. nov. Cheilanthes chipinquensis Knobloch & Lellinger, Amer. Fern J. 59: 8. 1969. Type: Mexico. Nuevo Leon: Chipinque Mesa, outside Monterey, Knobloch 1996B (holotype: MSC; isotypes: F, GH, MEXU, MICH, UC, US). urn:lsid:ipni.org:names:77134845-1


6) Myriopteris cinnamomea(Baker) Grusz & Windham, comb. nov. Notholaena cinnamomea Baker in Hook. & Baker, Syn. Fil. ed. 2. 515. 1874. Cheilanthes cinnamomea (Baker) Domin., Biblioth. Bot. 20: 133. 1913. hom. illeg. non Cheilanthes cinnamomea D. C. Eaton, Proc. Amer. Acad. Arts 18: 186. 1883. Type: Guatemala. Mo[n]tagua, 1862, Salvin & Goodman s.n. (holotype: K; isotype: BM). urn:lsid:ipni.org:names:77134870-1

Cheilanthes tryonii T. Reeves, Brittonia 32: 504. 1980.

In Cheilanthes, this species has been called Cheilanthes tryonii T. Reeves because use of the oldest applicable epithet (based on Notholaena cinnamomea Baker) was blocked by the earlier publication of Cheilanthes cinnamomea D. C. Eaton (Reeves 1980). With the transfer of this species to Myriopteris, we revert to the older epithet.


7) Myriopteris clevelandii (D. C. Eaton) Grusz & Windham, comb. nov. Cheilanthes clevelandii D. C. Eaton, Bull. Torrey Bot. Club 6: 33. 1875. Type: USA. California: Growing on a mountain about forty miles from San Diego at an elevation of about 2500 feet, Cleveland s.n. (holotype: YU; isotypes: GH, P, US). urn:lsid:ipni.org:names:77134846-1


8) Myriopteris cooperae (D. C. Eaton) Grusz & Windham, comb. nov. Cheilanthes cooperae D. C. Eaton, Bull. Torrey Bot. Club 6: 33. 1875. Type: USA. California: near Santa Barbara, Mrs. Ellwood Cooper (syntype: YU); Sierra Valley, Lemmon s.n. (syntype: YU). urn:lsid:ipni.org:names:77134847-1


9) Myriopteris covillei (Maxon) Á. Löve & D. Löve, Taxon 26: 325. 1977. Cheilanthes covillei Maxon, Proc. Biol. Soc. Wash. 31: 147. 1918. Type: USA. California: Surprise Canyon, Panamint Mountains, 13 April 1891, 1550 meters, Coville & Funston 593 (holotype: US). urn:lsid:ipni.org:names:77134848-1


10) Myriopteris cucullans (Fée) Grusz & Windham, comb. nov. Cheilanthes cucullans Fée, Mém. Fam. Foug. 7: 39, t. 25, f. 4. 1857. Type: Mexico, ad vallem Mexicanum, Schaffner 82 [holotype: RB; isotypes: K, US (fragment)]. urn:lsid:ipni.org:names:77134873-1


11) Myriopteris fendleri (Hook.) E. Fourn., Mex. Pl. 1: 125. 1872. Cheilanthes fendleri Hook., Sp. Fil. 2: 103, p. 107b. 1852. Type: USA. New Mexico, 1847, Fendler 1015 [holotype: K; isotypes: GH, MO, NY, US (fragment)].


12) Myriopteris × fibrillosa(Davenp.) Grusz & Windham, comb. nov. Cheilanthes lanuginosa var. fibrillosa Davenp., Bull. Torrey Bot. Club 12: 21. 1885. Cheilanthes fibrillosa (Davenp.) Davenp., Bull. Torrey Bot. Club 15: 225. 1888. Type: USA. California: San Jacinto Mountains, June 1882, Parish & Parish s.n. (holotype: GH). urn:lsid:ipni.org:names:77134880-1


13) Myriopteris fimbriata (A. R. Sm.) Grusz & Windham, comb. nov. Cheilanthes microphylla (Sw.) Sw. var. fimbriata A. R. Sm., Amer. Fern J. 70: 19, 21., f. 9–10. 1980. Type: Mexico. Chiapas: Munic. Frontera Comalapa, 6–8 km east of Frontera Comalapa, Breedlove 39018 (holotype: DS). urn:lsid:ipni.org:names:77134881-1

Cheilanthes fimbriata (A. R. Sm.) Mickel & Beitel, Mem. New York Bot. Gard. 46: 112. 1988. hom. illeg., non Cheilanthes fimbriata Vis., Fl. Dalmat. 1. 42 t. 1 f. 1. 1842.


14) Myriopteris gracilis Fée, Mém. Fam. Foug. 5: 150, t. 29, f. 6. 1852. Cheilanthes gracilis (Fée) Mett. ex Riehl, Abh. Senckenberg. Naturf. Ges. 80. 1859. hom. illeg., non Cheilanthes gracilis (Michx.) Kaulf., Enum. Filic. 209. 1824. Type: USA. Missouri: Jefferson County, Habitat ad rupes circa Hillsboro, Americâ septentr., Riehl 529 (isotypes: MO, US).

Cheilanthes feei T. Moore, Index Fil., 38. 1857.

Myriopteris lanuginosa J. Sm. Hist. Fil. 280. 1875. [non M. lanuginosa (Mart. & Gal.) E. Fourn. Mexic. Pl. 1: 125. 1872.]

In Cheilanthes, this has been called Cheilanthes feei T. Moore because use of the oldest applicable epithet (based on Myriopteris gracilis Fée) was blocked by the earlier publication of Cheilanthes gracilis (Michx.) Kaulf. With the transfer of this species to Myriopteris, we revert to the original name published by Fée in 1852.


15) Myriopteris gracillima (D. C. Eaton) J. Sm., Hist. Fil. 280. 1875. Cheilanthes gracillima D. C. Eaton, Rep. U.S. Mex. Bound. Botany 2: 234. 1859. Type: USA. Oregon: Cascade Mountains, 7000 feet of altitude, latitude 44°, Bigelow s.n. (lectotype: YU).


16) Myriopteris intertexta (Maxon) Grusz & Windham, comb. nov. Cheilanthes covillei Maxon subsp. intertexta Maxon, Proc. Biol. Soc. Wash. 31: 149. 1918. Cheilanthes intertexta (Maxon) Maxon in Abrams, Ill. Fl. Pacific States 1: 28. 1923. Type: USA. California: Santa Clara County, Santa Cruz Mountains, collected at the top of Black Mountain, 6 July 1903, Dudley s.n. (holotype: DS). urn:lsid:ipni.org:names:77134849-1


17) Myriopteris jamaicensis (Maxon) Grusz & Windham, comb. nov. Cheilanthes jamaicensis Maxon, Contr. U.S. Natl. Herb. 24: 51. 1922. Type: Jamaica. Below Cinchona, 28 February 1919, Harris 12905 (holotype: US; isotypes: GH, MO, NY). urn:lsid:ipni.org:names:77134850-1


18) Myriopteris lanosa (Michx.) Grusz & Windham, comb. nov. Nephrodium lanosum Michx. Fl. Bor.-Amer. 2: 270. 1803. Cheilanthes lanosa (Michx.) D. C. Eaton, Rep. U.S. Mex. Bound., Botany 2: 234. 1859. Type: USA. Tennassee (sic) et Carolinae septentrionalis (non designatus). urn:lsid:ipni.org:names:77134851-1

Myriopteris vestita (Sw.) J. Sm., Cul. Ferns 29. 1857. (fide C. Chr. 1906.) Adiantum vestitum Spreng., Anleit. Kenntn. Gew. 3: 122. 1804.


19) Myriopteris lendigera (Cav.) Fée, Mém. Fam. Foug. 5: 149. 1852 (as Myriopteris lentigera). Pteris lendigera Cav., Descr. Pl. 268. 1801. Cheilanthes lendigera (Cav.) Sw., Syn. Fil. 128, 328. 1806. Type: Mexico. Hidalgo: Ixmiquilpan en la Nueva España, Nee s.n. [syntype: MA, US (fragment)]; Ecuador. Bolivar: junto á Guaranda en el Reyno de Quito, Nee s.n. (syntype: MA).

Cheilanthes minor Mart. & Gal. Mém. Act. Brux. 75, pl. 21, f. 1. 1842. Myriopteris minor (Mart. & Gal.) Fée, Mém. Fam. Foug. 5: 150. 1852.

Cheilanthes lanuginosa Mart. & Gal. Mém. Act. Brux. 75, pl. 20, f. 2. 1842. Myriopteris lanuginosa (Mart. & Gal.) E. Fourn. Mex. Pl. 1: 125. 1872.

Myriopteris villosa Fée, Mém. Fam. Foug. 5: 149. t. 28, f. 1. 1852.

Cheilanthes frigida Linden ex T. Moore, Gard. Chr. 772. 1857. Myriopteris frigida (Linden ex T. Moore) J. Sm. Cat. Cult. Ferns 28. 1857.

Myriopteris lendigera (Cav.) J. Sm., Cat. Cult. Ferns 28. 1857. hom. illeg.

Pomataphytum pocillatum M. E. Jones, Contributions to Western Botany 16: 12. 1930.


20) Myriopteris lindheimeri (Hook.) J. Sm., Bot. Voy. Herald. 340. 1856. Cheilanthes lindheimeri Hook., Sp. Fil. 2: 101, t. 107a. 1852. Type: USA. Western Texas, 1847, Lindheimer 744 [lectotype: K; isolectotypes: GH, P (2 sheets), SD, US, YU].


21) Myriopteris longipila (Baker) Grusz & Windham, comb. nov. Cheilanthes longipila Baker, Ann. Bot. (Oxford) 5: 211. 1891. Type: Mexico. San Luis Potosí, 22°N Lat., 6000–8000 ft., Parry & Palmer 989 [holotype: K; isotype: US (fragment)]. urn:lsid:ipni.org:names:77134852-1


22) Myriopteris longipila subsp. brevipila (Mickel) Grusz & Windham, comb. nov. Cheilanthes longipila var. brevipila Mickel, Mem. New York Bot. Gard. 88: 198–199, f. 84N–Q, 87J–M. 2004. Type: Mexico. Guerrero: 2 km al SE de Amatitlán, 1600 m, 13 August 1994, Soto 1052 (holotype: NY; isotype: FCME). urn:lsid:ipni.org:names:77134882-1


23) Myriopteris marsupianthes Fée, Mém. Fam. Foug. 5: 149, t. 12A, f. 1. 1852. Cheilanthes marsupianthes (Fée) T. Reeves ex Mickel & A. R. Sm. Mem. New York Bot. Gard. 88: 201, f. 83M–P. 2004.Type: Mexico. Veracruz: Pic d’Orizaba, Martens & Galeotti 6256 (holotype: P; isotype: BR).


24) Myriopteris maxoniana (Mickel) Grusz & Windham, comb. nov. Cheilanthes maxoniana Mickel, Mem. New York Bot. Gard. 88: 201, f. 87A–D. 2004. Type: Mexico. Tamaulipas: San Lucas, Viereck 76 (holotype: US). urn:lsid:ipni.org:names:77134853-1


25) Myriopteris mexicana (Davenp.) Grusz & Windham, comb. nov. Cheilanthes mexicana Davenp., Bull. Torrey Bot. Club 15: 227. 1888. Type: Mexico. Chihuahua: on the verge of a high cliff near the summit of Potrero Peak (Santa Eulalia Mts.), October 1886, 7300 ft., Pringle 827 (holotype: GH; isotypes: MO, BR, DS, NY, P, UC, US, YU). urn:lsid:ipni.org:names:77134854-1


26) Myriopteris mickelii (T. Reeves) Grusz & Windham, comb. nov. Cheilanthes mickelii T. Reeves, Brittonia 32: 502, f. 1–5. 1980. Type: Mexico. Oaxaca: Distr. Yautepec, Mickel 4210 (holotype: NY; isotypes: MO, UC). urn:lsid:ipni.org:names:77134855-1


27) Myriopteris microphylla (Sw.) Grusz & Windham, comb. nov. Adiantum microphyllum Sw., Prodr. 135. 1788. Cheilanthes microphylla (Sw.) Sw., Syn. Fil. 127. 1806. Type: Jamaica, Swartz s.n. (holotype: S). urn:lsid:ipni.org:names:77134856-1


28) Myriopteris moritziana (Kunze) Grusz & Windham, comb. nov. Cheilanthes moritziana Kunze, Linnaea 23: 307. 1850. Type: Venezuela. Caracas: La Guayra, Moritz 263 (lectotype: B; isolectotype: GH). urn:lsid:ipni.org:names:77134857-1


29) Myriopteris myriophylla (Desv.) J. Sm., Bot. Voy. Herald, 340. 1856. Cheilanthes myriophylla Desv., Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 5: 328. 1811. Type: South America. Anon. s.n. (holotype: P).

Cheilanthes elegans Desv. Ges. Naturf. Freunde Berlin Mag. 5: 328. 1811. Myriopteris elegans (Desv.) J. Sm., Cat. Cult. Ferns 29. 1857.

Cheilanthes paleacea Mart. & Gal., Mém. Foug. Mexique 76, pl. 21, f. 2. 1842. Myriopteris paleacea (Mart. & Gal.) Fée, Mém. Fam. Foug. 5: 149, t. 29, f. 6. 1852.

Myriopteris intermedia E. Fourn., Bull. Soc. Bot. Fr. 27: 328. 1880. hom. illeg., non Fée, Mém. Fam. Foug. 5: 149. 1852.


30) Myriopteris newberryi(D. C. Eaton) Grusz & Windham, comb. nov. Notholaena newberryi D. C. Eaton, Bull. Torrey Bot. Club 4: 12. 1873. Cheilanthes newberryi (D. C. Eaton) Domin, Biblioth. Bot. 20: 133. 1913. Types: USA. California: San Diego, 9 November 1857, Newberry 1352 (syntype: MO, YU); San Diego, 1866, Wood s.n. (syntype: YU); Southern California: S. W. corner of San Bernardino County, rocks in the Temescal range, 22 January 1861, W. H. Brewer s.n. (syntype: YU). urn:lsid:ipni.org:names:77134858-1


31) Myriopteris notholaenoides (Desv.) Grusz & Windham, comb. nov. Pteris notholaenoides Desv., Mém. Soc. Linn. Paris 6: 299. 1827. Cheilanthes notholaenoides (Desv.) Maxon ex Weath., Contr. Gray Herb. 114: 34. 1936. Type: Hispaniola, Anon. s.n. (holotype: P). urn:lsid:ipni.org:names:77134859-1


32) Myriopteris × parishii (Davenp.) Grusz & Windham, comb. nov. Cheilanthes parishii Davenp., Bull. Torrey Bot. Club 8: 59. 1881. Type: USA. California: San Diego County, W. J. Parish s.n. (holotype: GH; isotypes: GH, YU). urn:lsid:ipni.org:names:77134860-1


33) Myriopteris parryi (D. C. Eaton) Grusz & Windham, comb. nov. Notholaena parryi D. C. Eaton, Amer. Naturalist 9: 351. 1875. Cheilanthes parryi (D. C. Eaton) Domin, Biblioth. 85: 133. 1913. Type: USA. Utah: C. C. Parry 263 (holotype: YU; isotypes: GH, US, YU). urn:lsid:ipni.org:names:77134861-1


34) Myriopteris peninsularis (Maxon) Grusz & Windham, comb. nov. Cheilanthes peninsularis Maxon, Contr. U.S. Natl. Herb. 10: 496. 1908. Type: Mexico. Baja California, T. S. Brandegee s.n. (holotype: US). urn:lsid:ipni.org:names:77134862-1


35) Myriopteris peninsularissubsp. insularis (Weath.) Grusz & Windham, comb. nov. Cheilanthes peninsularis (Maxon) var. insularis Weath., Amer. Fern J.21: 25. 1931. Type: Mexico. Socorro Island, Mason 1616 (holotype: CAS). urn:lsid:ipni.org:names:77134884-1


36) Myriopteris pringlei (Davenp.) Grusz & Windham, comb. nov. Cheilanthes pringlei Davenp., Bull. Torrey Bot. Club 10: 61, t. 34. 1883. Type: USA. Arizona: C. G. Pringle s.n. (holotype: GH; isotypes: DS, MO, NY, US, YU). urn:lsid:ipni.org:names:77134863-1


37) Myriopteris pringlei subsp. moncloviensis (Baker) Grusz & Windham, comb. nov. Cheilanthes moncloviensis Baker, Ann. Bot. (Oxford) 5: 210. 1891. Cheilanthes pringlei var. moncloviensis (Baker) Mickel, Mem. New York Bot. Gard. 88: 207–208, f. 79J–M. 2004. Type: Mexico. Coahuila: Soledad, E. Palmer 1378 (holotype: K; isotypes: MO, NY, US). urn:lsid:ipni.org:names:77134864-1


38) Myriopteris rawsonii(Mett. ex. Kuhn) Grusz & Windham, comb. nov. Cheilanthes rawsonii Mett. ex. Kuhn, Filices Africanae 75. 1868. Type: Africa. Cape Province: Namaqualand, between Specktakel and Komaggas, Whitehead s.n. (holotype: BM; isotype: K). urn:lsid:ipni.org:names:77134878-1


39) Myriopteris rufaFée, Mém. Fam. Foug. 8: 77. 1857. Type. Mexico. Veracruz: Volcan de Orizaba, Schaffner 83 (holotype: P?; isotype: RB?).

Cheilanthes eatonii Baker in Hook. & Baker, Syn. Fil. 140. 1867.

Cheilanthes castanea Maxon, Proc. Biol. Soc. Wash. 32: 111. 1919.

In Cheilanthes, this has been called Cheilanthes eatonii Baker. Examination of putative type specimens of Myriopteris rufa housed at RB (digital image) and P indicates that the latter name very likely represents the same species as broadly defined by recent authors (e.g., Mickel and Smith 2004). Because Myriopteris rufa (published in 1857) has priority over Cheilanthes eatonii (1867), we take up Fée’s original name for this taxon in Myriopteris.


40) Myriopteris scabra (C. Chr.) Grusz & Windham, comb. nov. Pellaea scabra C. Chr., Index Filic. 483. 1906. Type: USA. Texas: crevices of rock on hills, Turkey Creek, 25 June 1849, Wright 824 (holotype: K; isotypes: GH, NY, US).

Cheilanthes aspera Hook., Sp. Fil. 2: 111, t. 108A. 1852. hom. illeg., non Cheilanthes aspera Kaulf., Linnaea 6(1): 186. 1831. urn:lsid:ipni.org:names:77134865-1

Cheilanthes horridula Maxon, Amer. Fern J. 8: 94. 1918.

In Cheilanthes, this has been called Cheilanthes horridula Maxon because use of the oldest legitimate epithet (based on Pellaea scabra C. Chr.) was blocked by the earlier publication of Cheilanthes scabra H. Karst. (Maxon 1918). With the transfer of this species to Myriopteris, we revert to the older, exceedingly appropriate epithet.


41) Myriopteris tomentosa (Link) Fée, Mém. Fam. Foug. 5: 149. 1852. Cheilanthes tomentosa Link, Hort. Berol. 2: 42. 1833. Type: Mexico. Anon. s.n. [holotype: B; isotypes: PH, US (fragment)].

Cheilanthes bradburii Hook., Sp. Fil. 2: 97, t. 109b. 1852. Myriopteris bradburii (Hook.) J. Sm. Hist. Fil. 280. 1875.


42) Myriopteris viscida(Davenp.) Grusz & Windham, comb. nov. Cheilanthes viscida Davenp., Bull. Torrey Bot. Club 6: 191. 1877. Types: USA. California: Eastern slope of the Sierra Nevada near San Gogorio Pass, April 1876, Parry & Lemmon 427 (syntype: NY); California/Nevada: Downieville Buttes and bluffs of White Water River on the Colorado Desert, April–May, Lemmon s.n. (syntype: NY). urn:lsid:ipni.org:names:77134866-1


43) Myriopteris windhamii Grusz, Amer. Fern J. 103: 113. 2013. Type: USA. Arizona: Huachuca Mountains, Windham 4165 (holotype: DUKE; isotypes: ARIZ, ASC, ASU, GH, MO, NMC, NY, TEX/LL, UNM, US, UT).

Cheilanthes villosa Davenp. ex Maxon, Proc. Biol. Soc. Wash. 31: 142. 1918.

In Cheilanthes, this has been called Cheilanthes villosa Davenp. ex Maxon. Because transfer of the epithet villosa to Myriopteris is blocked by the earlier publication of Myriopteris villosa Fée (= Myriopteris lendigera fide Reeves 1979), we use the replacement name for this distinctive taxon published by Grusz (2013).


44) Myriopteris wootonii (Maxon) Grusz & Windham, comb. nov. Cheilanthes wootonii Maxon, Proc. Biol. Soc. Wash. 3: 146. 1918. Type: USA. Arizona: Santa Rita Mountains, Wooton s.n. (holotype: US). urn:lsid:ipni.org:names:77134867-1


45) Myriopteris wrightii (Hook.) Grusz & Windham, comb. nov. Cheilanthes wrightii Hook., Sp. Fil. 2: 87, t. 110A. 1858. Type: USA. Texas–New Mexico: Wright 823 (holotype: K; isotypes: GH, NY, US). urn:lsid:ipni.org:names:77134868-1


46) Myriopteris yatskievychiana (Mickel) Grusz & Windham, comb. nov. Cheilanthes yatskievychiana Mickel, Mem. New York Bot. Gard. 88: 212–213, f. 74F–K. 2004. Type: Mexico. Sonora: Sierra del Aliso, A. Búrquez M. 96-302 (holotype: MO). urn:lsid:ipni.org:names:77134869-1


47) Myriopteris yavapensis (T. Reeves ex Windham) Grusz & Windham, comb. nov. Cheilanthes yavapensis T. Reeves ex Windham, Contr. Univ. Michigan Herb. 19: 32. 1993. Type: USA. Arizona: Yavapai County, Windham 202 (holotype: UT; isotypes: ASC, ASU, US). urn:lsid:ipni.org:names:77134879-1


Name of uncertain application

Myriopteris cheiloglyphisFée, Mém. Fam. Foug. 8: 77. 1857.


Excluded names

Myriopteris contracta(Kunze) Fée, Mém. Fam. Foug. 5: 149. 1852. = Cheilanthes contracta (Kunze) Mett. ex Kuhn

Myriopteris hirta(Sw.) J. Sm., Ferns Brit. and For. 174. 1866. = Cheilanthes hirta Sw.

Myriopteris induta (Kunze) Fée, Mém. Fam. Foug. 5: 149. 1852. = Cheilanthes induta Kunze

Myriopteris intermedia(Kunze) Fée, Mém. Fam. Foug. 5: 149. 1852. = Cheilanthes hirta Sw. fide Christensen (1906)

Myriopteris macleaniiJ. Sm., Hist. Fil. 280. 1875. = Cheilanthes pilosa Goldm. fide Christensen (1906)

Myriopteris scariosa(Sw.) Fée, Mém. Fam. Foug. 5: 149, t. 29, f. 6. 1852. = Cheilanthes scariosa Sw.

Myriopteris szovitzii(Fisch. & Meyer) J. Sm., Hist. Fil. 281. 1875. = Cheilanthes persica (Bory) Mett. ex Kuhn fide Christensen (1906)

Acknowledgements

The authors thank A. R. Smith, R. Moran, K. N. Gandhi, and L. J. Dorr for assistance interpreting and/or obtaining obscure taxonomic literature. We also extend our appreciation to K. M. Pryer, G. J. Gastony, G. Yatskievych, L. Huiet, E. M. Sigel, F.-W. Li, and C. J. Rothfels for helpful comments on the manuscript. This study was completed in partial fulfillment of a doctoral dissertation in Biology at Duke University by the first author. Research support to A. L. G. was provided by a Society for Systematic Biologists Graduate Student Research Award, the American Society of Plant Taxonomists Shirley and Alan Graham Graduate Student Research Grant, as well as an NSF Doctoral Dissertation Improvement Grant (NSF-DDIG 1110767). Additional funding for this project was provided by NSF-DEB 0717398 awarded to M.D.W.

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