Adiantum capillus-veneris
Adiantum capillus-veneris L.
(Latin: capillus, hair, and veneris, pertaining to Venus, Roman goddess of love, beauty, and fertility, = Venus’ hair)
Local names: southern maidenhair, Venus’-hair fern, culantrillo, mattress fern
Terrestrial or on rocks; rhizomes short-creeping; leaves weakly deciduous, clumped or closely spaced, numerous, laxarching or pendulous, 15–75 cm tall; petioles and rachises usually blackish, or purplish black, occasionally somewhat brownish; leaf blades 2–3(–more) pinnate, glabrous, membranous to thin-herbaceous, bright green, the ultimate segments usually wedge or fan-shaped to irregularly rhombic (= 4-sided, diamond-shaped), ca. as long as broad; 2n = 120 (tetraploid; Paris 1993). Continuously moist calcareous areas, particularly limestone bluffs, rocks and ledges along streams; widespread in TX except far s, common in the Edwards Plateau, with somewhat disjunct populations in East TX in Harris (J.W. Kessler 3451, BRIT), Newton (TAES), Orange (Correll 13336, TEX-LL), Washington (Turner et al. 2003), and Webb (Rob Fondren, pers. comm.) cos.; s 1⁄2 of U.S. from VA s to FL w to CA, also disjunct to SD and B.C.; also Mexico, West Indies, Central and South America, Eurasia, and Africa. Sporulating May–Dec. [A. capillus-veneris var. modestum (Underw.) Fernald, A. capillus-veneris var. rimicola (Sloss.) Fernald] Although the species is variable, recognition of infraspecific taxa does not seem warranted (Mickel & Smith 2004). Venus’-hair fern has long been used medicinally for conditions of the skin, scalp, and internal organs (Cheatham & Johnston 1995). Hoshizaki and Moran (2001) considered this species, widespread in warm-temperate to subtropical areas, to be one of the most widely distributed ferns in the world. However, the Old World representatives are apparently diploid, with 2n = 60 (Manton 1950; Paris 1993), and it is possible that North American and Old World plants are actually different species (Paris 1993). The distribution in North America is interesting—the species is widespread across the s . of U.S., with an outlying population in the Black Hills of SD and a significantly disjunct population in British Columbia, Canada (Wagner 1972). This isolated Canadian occurrence is presumably the result of long-distance dispersal. Wagner (1972) noted that the British Columbia population of this “south-temperate to subtropical fern is flourishing in the runnels of a system of hot springs, an obviously unusual site.” Jim Peck (pers. comm.) pointed out that “likewise, it occurs on tufa of hot springs in Hot Springs, AR.”