A new tree fern species from southeastern Brazil: Cyathea myriotricha (Cyatheaceae)

A new tree fern species from southeastern Brazil: Cyathea myriotricha (Cyatheaceae) ROBBIN C. MORAN 1,JEFFERSON PRADO 2,PAULO H. LABIAK 3, JUDITH GARRISON HANKS 4, AND ERIC SCHUETTPELZ 5 1 The New York Botanical Garden, Bronx, NY 10456 5126, U.S.A.; e-mail: rmoran@nybg.org 2 Instituto de Botânica, C.P. 3005 CEP 01061 970, São Paulo, SP, Brazil; e-mail: jprado.01@uol. com.br 3 Departamento de Botânica, Universidade Federal do Paraná, C.P. 19031 CEP 81531 980, Curitiba, PR, Brazil; e-mail: plabiak@ufpr.br 4 Department of Biology, Marymount Manhattan College, 221 East 71st Street, New York, NY 10021, USA; e-mail: jhanks@mmm.edu 5 Department of Biology, Duke University, Durham, NC 27708 0338, USA; e-mail: ejs7@duke.edu Abstract. Morphological and plastid rbcl and trng-r sequence data suggest that the fern currently recognized as Megalastrum lasiernos (Dryopteridaceae) is in fact a tree fern (Cyatheaceae) and a member of the Cyathea clade. Accordingly, a new combination is made: Cyathea myriotricha. Based on morphological and ecological similarities, this species appears most closely related to C. aterrima. Both species are described and illustrated herein. Key Words: ferns, tree ferns, pteridophytes, taxonomy. While preparing a treatment of the Brazilian species of the fern genus Megalastrum (Dryopteridaceae), we examined specimens on loan of M. lasiernos (Spreng.) A. R. Sm. & R. C. Moran, a species endemic to southeastern Brazil. Although this species has been consistently treated as dryopteroid (Baker, 1870; Diels, 1899; Christensen, 1906, 1920; Brade, 1972; Smith & Moran, 1987), some of its morphological characteristics actually suggest cyatheoid affinity. To resolve this discrepancy, we studied M. lasiernos in greater detail, looking at aspects of both vegetative and reproductive morphology (including spores). We also obtained plastid rbcl and trng-r sequence data to determine its phylogenetic position. Our findings are reported herein. Materials and methods Herbarium specimens were examined from B, F, GH, K, MBM, MICH, MO, NY, P, RB, S, SP, UC, UPCB, and US. Field observations of living plants were also made in January 2008 by two of us (Prado and Labiak). To study characteristics of the Megalastrum lasiernos perispore, spores were transferred with dissecting needles from herbarium specimens to aluminum SEM stubs, where they were affixed with an asphalt adhesive and coated with a gold-palladium alloy in a sputter coater for 2.5 minutes. Spores were digitally imaged using a JEOL JSM-5410LV scanning electron microscope equipped with a JEOL Orion 5410 software interface, at an accelerating voltage of 15 kv. Plastid rbcl and trng-r sequences were obtained from Megalastrum lasiernos (voucher: Prado 1772, SP) following established protocols (Korall et al., 2007). Using BLAST (Altschul et al., 1990), we identified these sequences (GenBank accession numbers: EU751604, EU751605) as definitively cyatheoid and most similar to sequences from Cyathea. As such, we appended them to previously published scaly tree fern alignments (Korall et al., 2007). The taxonomic sampling Brittonia, 60(4), 2008, pp. 362 370 ISSUED: 1 December 2008 2008, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A.

2008] MORAN ET AL.: NEW TREE FERN 363 outside of the Cyathea clade was reduced in each of the single-gene alignments, and a combined (rbcl + trng-r) dataset was assembled. This combined dataset was analyzed using GARLI (Genetic Algorithm for Rapid Likelihood Inference) version 0.951 (Zwickl, 2006), employing the GTR+I+G model of DNA sequence evolution. Ten independent runs were conducted, each from a random starting topology, using the default settings recommended by the author. To assess branch support, non-parametric bootstrap analyses (with 1000 replicates) were also carried out in GARLI (with the model and settings as above). Results and discussion The placement of Megalastrum lasiernos among cyatheoid ferns is morphologically supported by the presence of mound-like receptacles, paraphyses, large sessile sporangia, wide oblique annuli, and trilete spores. These reproductive characters, although numerous, are easily overlooked and are mostly obscured by the dense pubescence of the laminae. The petiole scales of Megalastrum lasiernos also suggest a close relationship to cyatheoid ferns because their marginal teeth are formed from a single cell, instead of from the united and projecting ends of two adjacent cells (the typical condition for dryopteroid ferns). Other characteristics of these scales in M. lasiernos, however, preclude the assignment of this species to a particular tree fern genus. The scales of M. lasiernos lack the dark apical setae characteristic of Alsophila, and although the body of the scale is composed of conform cells, their marginal teeth are not darkened as is typical for Neotropical species of Sphaeropteris (i.e., the Sphaeropteris horrida group sensu Tryon, 1971). Studies of M. lasiernos spores using the scanning electron microscope (Fig. 1; others available publicly at www.plantsys tematics.org) were more conclusive, indicating that this species whose spores are verrucate with scattered minute rodlets is best accommodated in Cyathea (Tryon & Tryon, 1982; Tryon & Lugardon, 1991). It has trilete spores, unlike those of any dryopteroid fern. Phylogenetic analysis of DNA sequence data confirmed this placement (Fig. 2). The sum of this morphological and genetic evidence necessitates a new combination for Megalastrum lasiernos in Cyathea: Cyathea myriotricha (see below). Based on further herbarium work, we found that Cyathea myriotricha most closely resembles C. aterrima, a species known from Venezuela to Peru (see specimens examined section below). Both species have similar petiole scales, laminar hairs, and cutting. Cyathea myriotricha and C. aterrima lack indusia and their spores are similar in being verrucate with tiny rodlets on the surface (Fig. 1). Remarkably, both species also grow in similar habitats: exposed rocks. This is an unusual habitat for Cyathea, which generally grows on wet, shady forest floors. According to information from specimen labels, the trunks in C. myriotricha and C. aterrima may be absent or, if present, up to one meter tall. Based on morphology, C. myriotricha and C. aterrima thus appear to be very closely related, but unfortunately, we were unable to obtain DNA sequences from C. aterrima to support or reject this hypothesis. Because of their morphological similarity, we provide descriptions and specimen citations below for both Cyathea myriotricha and C. aterrima. The former differs from the latter only in having hairs on the margins of the laminae (versus absent), hairs between the veins adaxially (versus absent), paraphyses longer than the sporangia and resembling the laminar hairs (versus shorter, reddish, and tortuous), and in lacking glands on all parts of the laminae (versus present). Cyathea myriotricha (Baker) R. C. Moran & J. Prado, comb. nov. Polypodium myriotrichum Baker, J. Bot. 23: 217. 1885. Type: Brazil. Minas Gerais: Serra do Caraça, s.d., Glaziou 15734 (holotype: K; isotypes: B, GH, H-n.v., MICH, P). (Figs. 1 C, D and 3, 4) Polypodium hirtulum Kunze in Stuedel, Nomen. Bot. 2: 341. 1824, nom. nov. for Polypodium hirsutum Sw., non Desv. (1811). Dryopteris hirtula (Kunze) C. Chr., Index Filic. 270. 1905. Ctenitis hirtula (Kunze) Brade, Bradea 1(15): 209. 1972. Type: Brazil [probably Minas Gerais], Freyreis s.n. (holotype S; isotype: H-n.v.). [The epithet hirtula is occupied in Cyathea by C. hirtula Mart.] Polypodium lasiernos Spreng., Syst. Veg. 4: 61. 1827, nom. illeg. superfl. for Polypodium hirsutum Sw. Ctenitis lasiernos (Spreng.) Copel., Ann. Crypt. Phyto-

364 BRITTONIA [VOL 60 FIG. 1. Spores of two species of Cyathea, with distal faces at left, proximal faces at right. A, B. C. aterrima. C, D. C. myriotricha. Scale bars = 10 μm. path. [Gen. Fil.] 5: 124. 1947. Megalastrum lasiernos (Spreng.) A. R. Sm. & R. C. Moran, Amer. Fern J. 77: 128. 1987. Type: the same of P. hirsutum cited above. Trunks non-arborescent, to 25 cm long, decumbent, scaly, the scales like those on the petioles. Leaves up to 0.6 m long; petioles up to 25 cm long, brown, non-spiny, densely pubescent throughout and scaly toward the base, the hairs ca. 3 mm long, 7 12-celled; the scales up to 10 0.4 mm, linear to filiform, en masse pale brownish, the cells conform (even at the base of the scale), conspicuously ciliate, the cilia lax, spreading, 1- or 2-celled; laminae 2-pinnate-pinnatisect, often drying dark brown or blackish adaxially, margins pubescent, nonglandular; pinnae 10 15 5 6 cm, equilateral, the basal pinnae widest at the middle; rachises, pinna rachises, and costae narrowly winged distally, abaxially densely pubescent and sparsely scaly, the hairs like those of the petioles (sometimes, upon drying, the basal cells collapsing and twisting at right angles to each other), patent, pale brown, the scales the same as those on the petiole; adaxially densely pubescent; veins pubescent and non-glandular on both surfaces, the hairs the same as those on the pinna rachises and costules; lamina tissue between the veins pubescent and non-glandular

2008] MORAN ET AL.: NEW TREE FERN 365 FIG. 2. Phylogeny resulting from maximum likelihood analysis of plastid rbcl and trng-r sequence data, supporting the placement of Cyathea myriotricha within tree ferns (bootstrap percentages 50 are shown). on both surfaces; pinnules ca. 3 cm long, sessile; segments ca. 3 mm wide; obtuse; sori non-indusiate, with conspicuously raised receptacle, paraphyses 0.7 1.0 mm long, longer than the sporangia, pale brown, resembling the hairs; spores verrucate, with scattered minute rodlets. Distribution and ecology. Southeastern Brazil (Minas Gerais, Paraná, and probably São Paulo); on wet open rocks, in crevices, or on steep rock faces, 700 1200 m. Additional specimens examined. BRAZIL. Minas Gerais: Ouro Preto; Laranjeiras, 1935, Badini 192 (RB); Serra do Itacolomi, 1936, Badini 314 (RB); Serra do Itacolomi, ad Tombadouro, 16 Sep 1898, Damazio 1785 (Herb. Schwacke 13544) (P, RB); locality illegible, without date, Damazio 5417 (UC). PARANÁ: Palmeira;

366 BRITTONIA [VOL 60 FIG. 3. Leaf variation in Cyathea myriotricha. A. Schwartsburd 846 (NY). B, D. Glaziou 15734 (MICH). C. Badini 192 (RB).

2008] MORAN ET AL.: NEW TREE FERN 367 FIG. 4. Cyathea myriotricha. A. Habit of plants on a steep rocky slope. B. Detail of fertile pinnae. C. Rhizome apex in longitudinal section. D. Cross section of rhizome. (Images A B by P. Labiak and C D by J. Prado). Rio das Pombas, 6 Jan 1949, Hertel 379 (MBM, RB); Mun. de Jaguariaíva, Lago Azul a ca. de 2 km da Sede da Prefeitura de Jaguariaíva (antiga Estação de Trem), 24 16 32 S, 49 41 27 W, 830 m alt., 3 Jan 2008, Prado et al. 1772 (MBM, NY, SP, UPCB); Mun. de Jaguariaíva, próximo ao Rio Jaguariaíva, 9 Jul 2005, Schwartsburd 846 (NY, UPCB). State unknown: s.d., Glaziou 20157 (P). Although the earliest specific epithet for this species is hirtula, that epithet is occupied in Cyathea by C. hirtula Mart. Cyathea myriotricha is unusual among cyatheoid ferns because it grows as an epipetric plant, on shady and wet rocks (Fig. 4). The rhizome is short (ca. 25 cm long), decumbent, scaly, but not spiny. The fronds are short (up to 0.6 m long; Fig. 3A F) compared to those of other cyatheoid ferns. During recent field work, two of us (Prado and Labiak) observed that the rhizome grows vertically and partially adhered to the rocks, and retains ca. 40 old petiole bases. Cyathea aterrima (Hook.) Domin, Pteridophyta 262. 1929. Alsophila aterrima Hook., Syn. Filic. 38. 1866. Sphaeropteris aterrima (Hook.) R. M. Tryon, Contr. Gray Herb. 200: 20. 1970. Type: Peru. San Martín: Tarapoto, in Monte Guayapurima, s.d., R.

368 BRITTONIA [VOL 60 FIG. 5. Leaf variation in Cyathea aterrima. A. van der Werff et al. 16214 (NY). B. Rodríguez et al. 1041 (NY). C. Knapp et al. 8522 (NY). D. van der Werff et al. 16327 (NY).

2008] MORAN ET AL.: NEW TREE FERN 369 Spruce 4713 (holotype: K-n.v.; isotypes: NY, P-n.v., US). (Figs. 1A,B, and 5) Trunks to 1 m tall, spiny, scaly, the scales like those on the petioles. Leaves to 1 m long; petioles 5 40 cm long, dark to light brown, mostly non-spiny but toward the base with short spines (modified scale bases) 1 1.5 mm long, densely pubescent throughout and scaly toward the base, the hairs ca. 3 mm long, 7 15-celled, spreading, whitish, the scales up to 20 0.4 mm, linear to filiform, en masse pale reddish or orangish, nearly entire except for a few singlecelled teeth, the cells conform (even at the base of the scale); laminae 2-pinnate-pinnatisect, oftendryingdarkbrownorblackishadaxially, margins glabrous or sparsely glandular, the glands ca. 0.1 mm long, 1- or 2-celled, reddish; pinnae 8 20 1 10 cm, equilateral, widest at the middle; rachises, pinna rachises, and costae abaxially densely pubescent and moderately scaly, the hairs 3.0 3.5 mm long, 10 20-celled (sometimes, upon drying, the basal cells collapsing and twisting at right angles to each other), patent, whitish to light brown, the scales to 10 0.4 mm long, linear to lanceolate, pale brownish, spreading, entire to laxly ciliate, adaxially like the abaxial surface but slightly less pubescent; veins pubescent on both surfaces (the adaxially surface slightly less so), the hairs 0.8 1 mm long, 7 15-celled (sometimes, upon drying, the basal cells collapsing and twisting at right angles to each other), whitish, laxly spreading, abaxially with scattered uniseriate scales; lamina tissue between the veins apparently glabrous on both surfaces, but often sparsely glandular, the glands ca. 0.1 mm long, 1- or 2-celled, reddish; pinnules 3 5 0.7 1.0 cm, sessile; segments up to 3 mm wide, obtuse; sori non-indusiate, with conspicuously raised receptacle, paraphyses 0.1 0.2 mm long, the same size or shorter than the sporangia, reddish brown; spores verrucate, with sparse low hemispherical deposits. Distribution and ecology. Venezuela, Colombia, Ecuador, Peru; open sunny rocks, in crevices, or on steep rock faces, 500 1300 m. Additional specimens examined. VENEZUELA. Táchira: 10 Jul 1983, H. van der Werff & Angel González 5276 (MO); 900 m, 19 Nov 1985, Henk van der Werff & F. Ortega 8036 (MO). COLOMBIA. Caquetá: Sierra de Chiribiquete, entre el Río de Los Musgos y el arco del triumfo, cerca a la pared com pinturas, 1 05 N, 72 40 W, 600 650 m, 18 19 Aug 1992, Franco et al. 3781 (NY). ECUADOR. Pichincha: Pahuma, 2000 m, 00 01 42 N 78 37 50 W, 19 Oct 1999, L. Suin & Grupo Post- Grado MO-QCNE 346 (MO). PERU. AMAZONAS: Bagua District, upper slopes and summit of Cerro Teyu, summit with sclerophyll scrub, 2 m tall, with many lichens, 05 15 56 S, 78 22 7 W, 1030 m, 22 Mar 2001, van der Werff et al. 16327 (NY); Idem, Cerro Tayu, ca. 1 hr. from Chiriaco, 5 15 56 S, 78 22 7 W, 800 m, 19 Mar 2001, van der Werff et al. 16214 (NY); Id., Distrito Imaza, Comunidad Aguaruna de Putuim, bosque primario, sobre roca arenítica y abundante material ornico, campau, 4 55 S, 78 19 W, 700 800 m, 14 Jun 1996, Rodríguez et al. 1041 (NY); Idem., Distrito de Imaza, Tayu Mujaji, Comunidad de Wawas, 5 15 56 S, 78 22 7 W, 1200 m, 21 Oct 1997, Vásquez et al. 24615 (NY). San Martín: Lamas, on old trail from Yumbatos to San Antonio de Cumbasa, S of Shapajilla, upper slopes of Cerro Isco, 6 22 S, 76 23 W, 600 800 m, 5 Oct 1986, Knapp et al. 8522 (NY); Tarapoto, [6 30 05 S, 76 21 57 W], 750 m, 10 Dec 1929, Williams 5985 (F). Cyathea aterrima is characterized by dense pale reddish or orangish petiole scales, dense pubescence on all surfaces of the laminae, and exindusiate sori. It was treated by Windisch (1977) in Sphaeropteris because of its scales, which consist of conform cells throughout, even at the base of the scale. But for the reasons given above, it is considered here to be a Cyathea. The specific epithet means very dark and probably refers to the color of the lamina, which often dries dark brown adaxially. This color can also occur in Cyathea myriotricha. Acknowledgments This research was funded by a grant to the senior author from the United States National Science Foundation (DEB 0717056) and a grant to the second author by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Proc. n. 303867/2004 3). We thank Dr. Brigitte Zimmer for sending us images of the type of Polypodium myriotrichum at B, Dr. Alan R. Smith for helpful discussions, and Pedro B. Schwartsburd and Leonardo von Linsingen for assisting two of us (Prado and Labiak) while collecting Cyathea myriotricha in the state of Paraná. David Conant gave helpful comments on the manuscript.

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