Cystopteris reevesiana
Cystopteris utahensis
Reeves' bladderfern, Southwestern brittle fern
Utah bladderfern
creeping, not cordlike, internodes usually long, with scattered persistent petiole bases, hairs absent;
scales tan to brown, ovate to lanceolate, radial walls thin, luminae tan.
creeping, not cordlike, internodes short, heavily beset with old petiole bases, hairs absent;
scales lanceolate, ± clathrate, radial walls dark brown, thick, luminae clear.
monomorphic, clustered at stem apex, to 45 cm, bearing sori throughout year.
monomorphic, clustered at stem apex, to 45 cm, nearly all bearing sori.
highly variable in color, from uniformly dark purple to uniformly straw-colored, but mostly dark purple at base, grading to straw-colored at junction with blade, shorter than blade, base sparsely scaly.
green to straw-colored throughout or darker near base, shorter than blade, base sparsely scaly.
ovate to elliptic, 2–3-pinnate, widest at or just below middle, apex short-attenuate;
rachis and costae lacking gland-tipped hairs or bulblets;
axils of pinnae with occasional multicellular, gland-tipped hairs.
deltate to narrowly deltate, 2-pinnate-pinnatifid, usually widest at or near base, apex short-attenuate;
rachis and costae with unicellular, gland-tipped hairs, misshapen bulblets present or absent;
axils of pinnae usually with multicellular, gland-tipped hairs.
usually perpendicular to rachis, not curving toward blade apex, margins dentate to crenate;
proximal pinnae pinnate-pinnatifid to 2-pinnate, ± equilateral, basiscopic pinnules not enlarged;
basal basiscopic pinnules mostly short-stalked, base truncate to obtuse, distal pinnae deltate to ovate.
typically perpendicular to rachis, not curving toward blade apex, margins serrate;
proximal pinnae pinnatifid to pinnate-pinnatifid, ± equilateral, basiscopic pinnules not enlarged;
basal basiscopic pinnules sessile or short-stalked, base truncate to obtuse, distal pinnae ovate to oblong.
directed into teeth and notches.
directed into teeth and notches.
cup-shaped to lanceolate, gland-tipped hairs absent.
cup-shaped, apex truncate, with scattered, unicellular, gland-tipped hairs.
spiny, usually averaging 33–41 µm. 2n = 84.
spiny, usually 39–48 µm. 2n = 168.
Cystopteris reevesiana
Cystopteris utahensis
The finely dissected leaves, dark petioles, creeping stems, smaller spores, and terrestrial habit distinguish Cystopteris reevesiana from C. fragilis in the southwest. On rock and at high elevations, however, C. reevesiana can have stems with short internodes and leaves that are reduced in size and dissection (resembling C. fragilis). In southern Colorado, the two species are sympatric in some areas and form triploid hybrids. Cystopteris reevesiana and C. bulbifera are the diploid progenitors of C. utahensis, which occasionally crosses with C. reevesiana to produce sterile triploid hybrids of intermediate morphology.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Cystopteris utahensis is an allopolyploid derived from the diploid species C. bulbifera and C. reevesiana (C. H. Haufler and M. D. Windham 1991). Because C. utahensis shares one parent (C. bulbifera) with C. tennesseensis and because of morphologic similarities between C. reevesiana and C. protrusa (the second diploid parent of C. tennesseensis), populations of C. utahensis were previously considered to have originated by long-distance dispersal from eastern populations of C. tennesseensis. Genetic studies using isozyme markers, however, indicated that C. utahensis was a distinct species and stimulated the discovery of morphologic criteria for distinguishing it from its eastern cousin. When combined with the geographic separation of the two tetraploids, the minor differences in indument features provide a means of circumscribing this genetically distinct species. Potential confusion in identifying C. utahensis arises because sterile triploid hybrids may form when it is sympatric with the more common diploid C. reevesiana.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
