Riccia sorocarpa Bisch.

Plant / epiphyte
apothecium of Leucoscypha ricciae grows on live gametophyte of Riccia sorocarpa

Riccia sorocarpa Bisch. Nova Acta Acad. I,eop.-
Carol. 17: 1053. 1835.
Riccia minima L. Sp. PI. 1139, in part. 1753.
Thalli rather small to medium-sized, 4r-9 mm. long, 1-4 times dichotomous, at first subradiate, forming later irregularly gregarious patches, minutely, regularly, and compactly reticulate above, sometimes nearly smooth on drying, of a bright, clear, subcrystalline lightgreen above when living, of a lighter green when dry, concolorous below; main segments oblong or obcuneate-oblong, 0.75-2 mm. wide; terminal segments oblong, subacute; margins usually sharply acute, naked, often hyaline and submembranous, rarely violet, commonly ascending, often incurved on drying; median sulcus acute; scales small, whitish or hyaline, often reaching the margin at or near the apices ; transverse sections subquadrate or somewhat parabolic, mostly 1-2, less often 2-4, times as broad as high, about 25 cells thick in median parts, the ventral outline strongly convex or subcarinate; dorsal epidermis 2 or 3-stratose, the cells of the primary stratum at first papilliform, the lower portions of their lateral walls becoming thickened and the upper soon vanishing, leaving persistent cups 30-75 /z broad attached to the likewise thick-walled cells of the subjacent stratum. Monoicous; antheridial ostioles short-cylindric, about 80 fi high; capsules usually numerous, somethnes emergent-protuberant with age; spores dark-brown, 67-100 ju (mostly 70-90 ju) in maximum diameter, angular, with a brownish granulate-papillate and crenulate, usually interrupted margin 3-6 /* broad, the outer face areolate, showing in profile papillae mostly 3-6 ju long, the areolae mostly 6-10 /i wide, the inner faces densely and rather minutely punctate or furnished with very short and numerous low ridges which do not form areolae.
Type hOCAhi'Tv: Near Heidelberg, Germany.
Distribution: Massachusetts to Washington, California, and Alabama; reported from Greenland; also in Europe, northern Asia, and northern Africa.