Innovations in the Fern Genus Phanerophlebia

Abstract

Phanerophlebia gastonyi, a new Mexican species, is described, and P. remotispora is reduced to varietal status under P. nobilis. The genus Phanerophlebia (Dryopteridaceae) comprises eight species of terrestrial ferns of the New World tropics and adjacent subtropical regions. It was last revised taxonomically by Underwood (1899) and Maxon (1912), whose studies were based on the relatively few herbarium specimens in existence at that time. A recently completed doctoral dissertation (Yatskievych, 1990) involving biosystematic studies of this genus has not been fully published, and a taxonomic revision based upon this research is currently in preparation. Evidence from several independent experimental data sources can be correlated with the results of a morphological study of the wealth of recently collected specimens of Phanerophlebia to provide a clearer picture of species limits in the group. The present note describes a new species and makes a new combination in Phanerophlebia. These names are needed for the forthcoming pteridophyte volume of Flora Mesoamericana. Phanerophlebia gastonyi Yatskievych, sp. nov. TYPE: Mexico. Ca. 13 km NW of Berri6zabal, limestone outcrops in evergreen tropical hardwood forest, elevation 1,000 m, 15 July 1985, Yatskievych, Gonzalez L., G. Ranker & C. Starr 85-182 (holotype, MO; isotypes, ARIZ, CHAPA, MEXU, IND, NY, UAMIZ, UC). Species habitu Phanerophlebiae juglandifoliae (Humboldt et Bonpland ex Willdenow) J. Smith simillima, sed differt statura minora; pinnis l-3(-4)-jugatis; paleis ad basem stipitis non imbricatis, bicoloribus, centro lato nigrescentibus, margine angusta pallidis; sporis 30-42 ,im longis; chromosomatum numero n = 41. Rhizomes to ca. 5 mm diam., short repent. Rhizome scales 2.5-4.5 mm long, 1.5-2 mm wide, ovate to elliptic-lanceolate, ciliate, bicolorous with broad, dark, sclerotic centers and narrow hyaline margins. Leaves to 45(-55) cm long, the petiole slightly shorter than to usually longer than lamina. Petiolar scales usually deciduous with age, mostly not overlapping, much like rhizome scales, the broadest 2 mm wide, the reduced hairlike scales uncommon among the broader scales. Pinnae 13(-4) pairs, to 12(-15.5) cm long, ovate to lanceovate, sometimes somewhat falcate, the apex acute to attenuate, the base obliquely cuneate to rounded, sometimes nearly equilateral, the margins entire to slightly undulate proximally, spinulose-serrulate only in distal half. Gemmiferous buds absent from axils of distal pinnae. Secondary veins with 1-3 series of regular marginal anastomoses, 2-4-branched. Sori in (1-)2-4 series between costa and margin, exindusiate. Spores monolete, 30-42 utm long. n = 41. Illustration. Mickel & Beitel (1988, as P. juglandifolia). Distribution. Moist soil, less commonly on fissured limestone rock faces, in cloud forests and montane rainforests; 900-2,200 m. Southern Mexico (Chiapas, Oaxaca, Veracruz). This species is named for the eminent American pteridologist, Gerald J. Gastony, whose advice and assistance has nurtured my developing interest in f rns for many years. It is an infrequently collected taxon and is known from very few sites. Specimens of P. gastonyi have previously been identified as P. juglandifolia. The latter species occurs from southern Mexico to northern Venezuela and Colombia. The two species are very similar morphologically, but can be differentiated by the characters in the following key: la. Petiolar scales not overlapping, 4-6 mm long, with broad, dark, sclerotic centers and narrow, hyaline margins; gemmiferous buds absent; spores 30-42 jum long . . Phanerophlebia gastonyi lb. Petiolar scales usually overlapping, 6-11 mm long, with dark brown central stripes and lighter margins of about equal width; gemmiferous buds often present on rachis in axils of distal pinnae; spores 41-60 jum long Phanerophlebia juglandifolia Yatskievych & Gastony (1987) discussed morphological and allozymic evidence that P. juglandifolia is an allotetraploid with diploid P. gastonyi as one of its parental taxa. They speculated that the diploid P. macrosora (Baker) L. Underwood might be the other progenitor, but were unable to confirm this. Yatskievych et al. (1988) used restriction site analysis of the chloroplast genome to confirm that P. gastonyi is a maternal parent of P. juglandifolia, NOVON 2: 445-446. 1992. This content downloaded from 157.55.39.58 on Sun, 11 Dec 2016 04:40:28 UTC All use subject to http://about.jstor.org/terms