Cystopteris bulbifera
Cystopteris bulbifera (L.) Bernh.
(Latin: bulbus, a swelling, and feros, to bear, bearing bulbs, in reference to the bulblets on the leaves)
Local names: bulblet bladder fern
Usually on rocks; rhizomes with scales, but without hairs; leaves clustered at tip of rhizome, monomorphic, to 75 cm long; petioles reddish to greenish or straw-colored; rachis and costae, and midribs of ultimate segments densely glandular-pubescent, the rachis and costae often with round, pea-like bulblets; leaf blades 2-pinnate to 2-pinnate-pinnatifid, usually narrowly deltate, sometimes ± broadly so, widest at base, apically long attenuate, the ultimate segments serrate; indusia usually with glandular hairs; 2n = 84 (Haufler et al. 1993). Moist calcareous cliffs, in crevices and on ledges; in TX known only from the Guadalupe Mts., Culberson Co. (Correll & Hanson 29803, BRIT, TEX-LL, “First Texas colleccystopteris tion,” BRIT sheet annotated by M.D. Windham; T.L. Burgess 3718, TEX-LL); e U.S. (except extreme se) w to AR and WI and se Canada, also disjunct to the w U.S. in AZ, NM, OK, TX, and UT. Sporulating ?–Jun–Aug–?. [Polypodium bulbiferum L.] This species was first reported from TX by Correll (1965). He discovered it in McKittrick Canyon in the Guadalupe Mts., whose canyons are “the most mesophytic and florally interesting” in Trans-Pecos, TX (Correll 1965). He also noted that it was “the southernmost locality known for this typically northern species.” It is now known that this is a species primarily of the e ½ of North America, with isolated populations in the mountains of AR, NM, OK, TX, and UT. These disjunct populations, which are separated by many hundreds of mi from others of their species, are presumably the result of long-distance dispersal The combination of leaves usually narrowly deltate, widest at base and long attenuate, with dense glandular pubescence and bulblets, is distinctive. Weakley (2010) noted that, “This species is a diploid involved in the reticulate evolution of Cystopteris in e. North America.” In the e U.S. C. bulbifera is known to hybridize with C. protrusa giving rise to the tetraploid C. tennesseensis Shaver (Haufler et al. 1990). In the sw U.S. C. bulbifera has hybridized with C. reevesiana giving rise to the tetraploid C. utahensis. The various hybrids usually have less glandular pubescence than C. bulbifera, are typically widest beyond the base, and have misshapen bulblets (Haufler et al. 1993). Because of morphological similarities and because both are tetraploids with one parent in common, C. tennesseensis (in the e U.S.) has sometimes been incorrectly treated as a synonym of the genetically distinct C. utahensis (of the w U.S.) (e.g., The Plant List 2011; Tropicos 2011). Because of its rareness and limited distribution in the state, we consider this species to be of conservation concern in TX.