Asplenium adiantum-nigrum var. gaudichaudi-anum Hook.; A. patens Kaulf. [Hillebrand's A. adian-tum-nigrum ~ var.]

Common names: 'iwa 'iwa

Indigenous

Greek adiantos, unwetted, +Latin nigrum, black or dark, possibly referring to the dark stipe.

Plants small to medium-sized, terrestrial. Rhizomes decumbent, tips thickly covered with old stipes. Fronds 8-40 x 5-12 cm, not proliferous. Stipes clustered, shiny· lower stipes dark brown, distal rachises hght green, colors remaining distinct and entirely separate over several cm, color of stipes gradually tapering to a point and ending in distal stipes or rachises; scales at bases linear, dark brown, shiny, with hair-like tips. Blades 2-to 3-pinnate, elongate­triangular, deltate to ovate, occasionally ovate-lanceolate, pale green, subcoriaceous, lustrous, basal pinnae longest. Pinnae 8-12 pairs, alternate, stalked, deltate to deltate-lanceolate. Pinnules short-stalked, lanceolate, stalks more or less winged, margins lobed to finely dentate at segment tips. Veins free, forked. Sori plentiful, medial, 3 mm or less long, often overlapping, older sori covering entire abaxial surface. Indusia thin.

Locally common on dry lava and cinders and also in open woods and shrub lands, 350-4,000 m, all major islands.

Native to Europe (where it is most com-mon), Africa, Eurasia, Mexico (Chihuahua), the southwestern United States, Pacific islands, and Taiwan. It apparently originated in Europe, as a fertile hybrid (an allotetraploid) between Asplenium cuneifolium and A. oropteris.

Asplenium adiantum-nigrum: a small to medium-sized, 2-pinnate to 3-pmnate fern may be distinguished by its habitat, glossy pinnae, and distinct pattern of sharp and pointed color change between the upper portions of stipes and the lower portions of the rachises.