Bommeria hispida

Bommeria hispida (Mett. ex Kuhn) Underw
(Latin: hispidus, hairy, bristly, or rough, in reference to the hairs on the leaves)

Local names: copper fern, dancing bommeria, hairy bommer

Plant terrestrial; rhizomes prostrate, long-creeping, often branched; leaves monomorphic, usually 7–10(–rarely more) mm apart on the rhizome; petioles light grayish brown; leaf blades broadly 5-sided in outline (= pentagonal), small, 7 cm or less long, ca. as wide or very slightly wider, pedately divided into 3 main segments, these deeply pinnate-pinnatifid, dark green but often becoming copper-colored or reddish with age, herbaceous; pinnae with straight needle-like hairs on upper surface, with scales, coiled hairs, and straight needle-like hairs on lower surface (the indumentum very light in color when young, yellowish tan to brownish at maturity), the veins free; rachis chestnut brown; sori along the distal half of the veins; indusia and false indusia absent; 2n = 60 (Haufler 1993). Rocky soil, rock crevices in mountains and canyons; Brewster (e.g., Warnock 21559, Correll 13621, BRIT), El Paso (e.g., R.D. Worthington 3858, BRIT), Jeff Davis (e.g., G.M. Soxman 459, TEX-LL), Presidio (Correll 13742, BRIT, TEX-LL), Culberson, and Hudspeth (Correll 1956) cos. in the Trans-Pecos; AZ, NM, and TX; also Mexico. Sporulating summer–fall. [B. schaffneri E. Fourn., Gymnogramma hispida Mett. ex Kuhn, Gymnogramma ehrenbergiana Klotzsch var. muralis Pringle ex Davenp., Gymnogramma schaffneri (E. Forn.) Baker, Gymnopteris hispida (Mett. ex Kuhn) Underw., Neurogramma hispida (Mett. ex Kuhn) Diels].

This was one of the first homosporous ferns shown to be obligately outcrossing—in other words, the eggs and sperm from a single gametophyte do not produce a sporophyte. Rather, sporophytes of B. hispida in nature are typically the result of outcrossing between genetically different gametophytes (Haufler & Soltis 1984)—this type of sexual reproduction is important because it ensures genetic variation among the offspring. Bommeria hispida is reportedly the only member of the genus known to occur n of Mexico (Haufler 1993) and the only one known to be in areas with subfreezing temperatures (Haufler 1979). Haufler (1979) noted that it can withstand more environmental stress than other members of the genus and that its “small leaf size, dissected segments, double palisade layer, and extensive and diverse indument” are adaptations to a high light-low humidity habitat. There are only two members of the family with pentagonal leaf blades in the Trans-Pecos, this species and Notholaena standleyi. Bommeria hispida has pinnae with scales, coiled hairs, and straight needle-like hairs beneath, while those of N. standleyi “have copious yellow or greenish farina but no hairs or scales” (Yarborough & Powell 2002). Also, when dry the leaves of Bommeria hispida curl so that the upper leaf surface is exposed; in contrast, leaf curling in N. standleyi causes the farina-covered lower surface to be exposed.

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