Marchantia paleacea Bertol.

Marchantia paleacea Bertol. Opusc. Sci
Bologna 1:242. 1817.
Marchantia papillata italica Raddi, Mem. Soc. Ital. Modena 19: 44. 1823. Fimbriaria paleacea Corda, in Opiz, Beitr. 648. 1829. Marchantia nepalensis Lehm. & Lindenb.; Lehm. Stirp. Pug. 4: 10. 1832. Marchantia nitida Lehm & Lindenb. ; Lehm. Stirp. Pug. 4:11. 1832. Marchantia squamosa Raddi; Lehm. Stirp. Pug. 4: 12, in part. 1832. Marchantia tholophora Bisch. Nova Acta Acad. Leop.-Carol. 17: 989. 1835. Marchantia calcarata Stephani, Bull. Herb. Boiss. 5: 98. 1897. Marchantia planipora Stephani, Bull. Herb. Boiss. 5: 98. 1897.
Thallus pale-green, often glaucous and sometimes purplish beneath and along the margin, mostly 2-4 cm. long and 0.5-0.8 cm. wide, the texture firm but scarcely leathery; epidermal' cells averaging about 43 X 30 m; surface-papillae lacking; pores usually bounded by 6 circles, of cells with 4 cells in each circle, those of the innermost circle enclosing a cruciate opening; ventral tissue with sclerotic cells and sometimes with slime-cells; ventral scales in four rows; appendages of median scales oblong to ovate-orbicular, mostly 0.6-0.75 mm. long and 0.450.6 mm. wide, rounded to acute at the apex and entire to vaguely dentate on the margin. Male receptacle borne on a stalk 5-7 mm. long, with 2 rhizoid-furrows, destitute of green tissue, mostly 5-6 mm. broad, shortly lobed, the lobes mostly 8, subsymmetrically spaced; female receptacle borne on a stalk 2-4 cm. long, with 2 rhizoid-furrows and a single broad band of green tissue, mostly 0.5 cm. wide, deeply rayed, the rays mostly 9, separated by subequal sinuses or with one sinus broader than the others, dilated at the truncate or emarginate apex, flat, without papillae; involucre deeply and irregularly lobed, the lobes long-acuminat& and with ciliate margins; spores brownish-yellow, about 34 ju in diameter, tetrahedral, with narrow wings and low surface-lamellae; elaters 6-8 ju wide. Cupules deeply lobed, the lobes acute to acuminate, dentate to short-spinose, destitute of papillae.
Type locality: Italy.
Distribution: Texas and Arizona to Guatemala; Cuba and Jamaica; also in Europe, Africa,, and Asia; on banks and rocks.