Riccia trichocarpa

Riccia trichocarpa M. A. Howe, Bull. Torrey Club
25: 184. 1898.
Riiccia ciliata Underw. Bull. 111. Lab. Nat. Hist. 2: 26. 1884. Not i^.ciZ/a^flHoffm. 1795. Riccia intumescens Underw. Bull. 111. Lab. Nat. Hist. 2: 26, in part. 1884. Not R. ciliata intumescens Bisch. 1835.
Riccia tumida Underw. Syst. Bot. N. Am. 9: 7. 1895. Not R, tumida Lindenb. 1829.
Thalli medium-sized, 3-7 times dichotomous, in rosettes 15-20 mm. in diameter or irregularly radiating, light-green and regularly reticulate above, often blackening below and at margins; main segments linear, 0.^5-1.5 (mostly 1) mm. wide; terminal segments obcuneate or oblong-elliptic, obtuse or subacute; margins rounded, tumid, often connivent on drying, the margins and sides densely clothed with white or tawny usually rigid, slender-pointed, rarely subuncinate, minutely granulate cilia 0.3-0.9 mm. long and with unequally thickened walls; median sulcus narrow and rather deep toward apex, obtuse or subacute, often nearly vanishing toward base; scales very inconspicuous; transverse sections sub quadrate-oblong, 1.25-3 times as broad high (mostly 1.25-2 times in non-geminate parts), 20-28 cells thick in median parts, the ventral outline slightly convex toward apex, otherwise nearly rectilinear; dorsal epidermis 2-gtratose, the cells of the primary stratum ovoid-papilliform or subhemispheric, soon collapsing and leaving irregular and finally inconspicuous vestiges, the cells of the succeeding stratum mostly 24-40 /x broad, often broader than high. Monoicous; antheridial ostioles elevated 50-100 ;n; capsules numerous, long included, the overlying epidermis commonly marked with a dark purple spot and nearly always bearing 1-12 cilia; spores soon black and very opaque, 90-125 m in maximum diameter, angular, with a granulate-papillate, interrupted, often obsolete margin 1-5 fx wide, the outer face areolate, with age commonly showing in profile crowded truncate granulate papillae 2-5 /* long, the areolae (visible only in young spores) 612 fi broad, the inner faces similarly marked but scarcely papillate.
Type I.OCAIJTY: Near Stanford University, California.
Distribution: Texas and California.