Flora of North America species comparison

to 20 per plant, blackish, usually extremely narrow, often almost hairlike, less than 0.1 mm diam., proliferations not reported.

unbranched, whitish yellow to black, 0.1-1.5 mm diam., smooth, commonly proliferous and forming clones.

spheric, 3-12 mm diam., succulent, cormlike with perforation at apex, apical meristem located at bottom of cavity through which leaves emerge at top, leaves 2 per stem.

upright, forming caudex, to 1.6cm thick (cormlike in O. crotalophoroides);

gemmae absent.

brown to white, narrowly linear, unbranched, 2-20 × 1-3mm diam. x =30.

stalk to 0.6cm, 0.1-0.2 times as long as trophophore blade.;

trophophore blade lying nearly flat on ground, not folded longitudinally, pale green throughout, deltate to cordate, to 3 × 2 cm, contracted abruptly at truncate to cordate base, apex with apiculum.

erect to prostrate, blades nearly sessile or stalked, lanceolate to cordate, simple, 0.4-100 mm × 0.3-45 mm;

margins entire;

apex rounded, acute, or apiculate;

veins anastomosing, main areoles to 15 × 4mm, but mostly less than 5 × 3 mm.

coarsely reticulate with included veinlets.

arising at ground level, 1-5 times as long as trophophore;

sporangial clusters usually short, less than 1 cm, 2-3 mm wide, with 3-8 pairs of sporangia, apiculum to 1.5 mm.

1 per leaf, simple, stalked, borne from ground level to well above ground at base of trophophore but commonly absent, leaf made up of only trophophyll.

clusters with sporangia in 2 rows, deeply sunken in simple, linear or oblong fleshy sporophore tip, tip usually ± apiculate.