Innovations in the Fern Genus Phanerophlebia George } atski(vyc/hMissouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166, U.S.A.ABSTRACT. Phanerophlebirt gastony\i, a new Mex-ican species, is described, and P. remotispora isreduced to varietal status under P. nobilis. The genus Phan'rophle'bia (Dryopteridaceae)comprises eight species of terrestrial ferns of theNew World tropics and adjacent subtropical regions.It was last revised taxonomically by Undlerwood(1899) and Maxon (1912), whose studies were basedon the relatively few herbarium specimens in exis-tence at that time. A recently completed doctoraldissertation (Yatskievvch, 1990) involving biosvs-tematic studies of this genus has not been fullypublished, and a taxonomic revision based upon thisresearch is currently in preparation. Evidence fromseveral independent experimental data sources canbe correlated with the results of a morphologicalstudy of the wealth of recently collected specimensof Phanerophlebia to provide a clearer picture ofspecies limits in the group. The present note describes a new species andmakes a new combination in PhInerop/hileia. Thesenames are needed for the forthcoming pteridophytevolume of Flora llsoameirictina.Phanerophlebia gastonyi Yatskievych, sp. nov. TYPE: Mexico. Ca. 13 km NW of Berriozabal, limestone outcrops in evergreen tropical hard-wood forest, elevation 1,000 in, 15 July 1985, }iaskiervcih, (;onzhile L., G. lRanke'r & C. Starr 85-182 (holotype. MO; isotypes, ARIZ, CIIAPA, MEXUI, IN1), NY, UAMIZ, UC). Species habitu Ihruinlcrophlebice juglar ii(i/litc (Humr-boldt et Bonpland ex Willdenow) J. Smith simiillirna, seddiffert statura rninora; pinnis 1 3( 4)-jugatis: paleis adbasem stipitis 11011 imbricatis, bicoloribus, centro lato ni-grescentibus, margine angusta pallidis; sporis 30 -42 pinlongis; chromosormaturn nurrero t = 41. Rhizomes to ca. 5 rmm diam., short repfent. Rhi-zome scales 2.5 1.5 mm long, 1.5 2 mm wide,ovate to elliptic-lanceolate, ciliate, bicolorous withbroad, dark, sclerotic centers and narrow hyalinemargins. Leaves to 45(-55) cm long, the petioleslightly shorter than to usually longer than lamina.Petiolar scales usually deciduous with age, mostlynot overlapping, much like rhizome scales, thebroadest 2 mm wide, the reduced hairlike scalesuncommlon among the broader scales. Pinnae I3(-4) pairs, to 12( 15.5) cm long. ovate to lance-ovate, sometimes somewhat falcate, the apex acuteto attenuate, the base obliquely cuneate to rounded,sometimes nearly equilateral, the margins entire toslightly undulate proximally. spinulose-serrulate onlyin distal half. (emmiferous buds absent from axilsof distal pinnae. Secondary veins with I 3 series ofregular marginal anastomoses, 2 -lbranched. Soriin (1 )2 4 series between costa and margin, exin-dusiate. Spores monolete, 30 42 pin long. n = 11. li/ustration. Mickel & Beitel (1988, as P. jug-lan li//i/t). l)istribution. Moist soil. less commonly on lis-sured limestone rock faces, in cloud forests andiiontane rainforests: 900 2,200 m. Southern Mex-ico (Chiapas, Oaxaca, Veracruz). This species is nanmed for the emiinenit Amerircanpteridologist. Gerald J. (astony, whose advice andassistance has nurtured my developing interest inferns for many years. It is an infrequently coll(ectedtaxon and is known from very few sites. Specimens of P. gaston i i have previously beenidentified as P. juglandifilia. The latter speciesoccurs from southern Mexico to northern \Veneizullaand Colombia. Tihe two species are very similarmorphologically, but can be differentiated by tIhecharacters in the following key:la. Petiolar scales not overlapping, 4 6) nun lonlg, with broad, dark, sclerotic centers and narrow, hyaline margins; genmriferous buds absent; spores 30-42 piin long . . Phanerophlebia ga slonyi lb. Petiolar scales usually overlapping, 6 11 ruin long, with dark brown central stripes and lighter margins of about equal width; gemmriferous buds often present on rachis in axils of distal pinnae; spores 41-60 pin long ......... ................. 'han 'roph h'lbia jiuglant d(t i li Yatskievych & Gastony (1987) discussed mor-phological and allozymic evidence tlhat P. jugiln-difilia is an allotetraploid with diploid P. gaston ias one of its parental taxa. T'hey speculated that thediploid P. macrosora (Baker) L. Underwood miightbe the other progenitor, but were unablle to confirmthis. Yatskievych et al. (1988) used restriction siteanalysis of the chloroplast genome to confirmi thatP. gastonyi is a maternal parent of P. jpuglandiifiia, NovoN 2: 445 446. 1992.