dcsimg

Comprehensive Description

provided by North American Flora
Riccia hirta Aust.; Underw. Bot. Gaz. 19: 274. 1894
Riccia arvensis hirta Aust. Proc. Acad. Phila. 1869: 232, 1870.
Thalli usually small, 3-9 mm. long, 1-4 times dichotomous, irregularly and often intricately gregarious, minutely, compactly, and rather obscurely reticulate above, becoming somewhat spongiose-furfuraceous on drying, glaucousgreen above when living, commonly albescent when dry, the margins and sides often tinged with dark-purple; main segments oblong, 0.6-1.5 mm. wide; terminal segments oblong, sub quadrateovate, or occasionally obovate, obtuse; margins subacute or, more often, obtuse and rounded, non-alate or weakly subalate, furnished with a few, mostly slender and sharp-pointed, rather rigid, nearly straight or slightly curved, minutely granulate cilia 50-150 /x long, these sometimes occurring also on the dorsal surface or now and then wholly wanting ; median sulcus narrow and rather obtuse, abruptly defined in younger parts, becoming shallow and obsolescent in older parts; scales few and inconspicuous, sometimes projecting very slightly at extreme apex, often dark-purple; transverse sections subquadrate or parabolic, mostly 1-2 times as broad as high, 20-30 cells thick in median parts, the cells chlorophyllose almost or quite to the ventral epidermis, the ventral outline rounded; dorsal epidermis 1or 2-stratose, the cells of the primary stratum rounded-obtuse or mammillate, soon collapsing and leaving irregular vestiges, or sometimes indurated and subpersistent, the cells of the succeeding stratum subglobose or ellipsoid, 24-40 IX broad, commonly broader than high. Monoicous; antheridial ostioles elevated 0-30 m; capsules usually numerous, often crowded, long included; spores yellowish-brown, becoming dark-brown with age, 90-135 {x in maximum diameter, angular, with a granular-papillate, crenulate, interrupted margin 3-12 ^ broad, the outer face areolate, showing in profile obtuse or truncate papillae 2-4 n long, the areolae mostly 10-13 ju wide, the inner faces less strongly or imperfectly areolate, scarcely papillate in profile.
Type i^ocaivITy: Closter, New Jersey. Distribution: Connecticut to Louisiana and Texas.
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bibliographic citation
Caroline Coventry Haynes, Marshall Avery Howe, Marshall Avery Howe, Alexander William Evans. 1923. SPHAEROCARPALES - MARCHANTIALES; SPHAEROCARPACEAE, RIELLACEAE; RICCIACEAE, CORSINIACEAE, TARGIONIACEAE, SAUTERIACEAE, REBOULIACEAE, MARCHANTIACEAE. North American flora. vol 14(1) New York Botanical Garden, New York, NY
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North American Flora