Marchantia tenella Linnaeus
Plants green with purplish undulate margins and purplish underside; branching dichotomous, rarely with intercalary branches. Thalli 6 15 ´ 1.5 3 mm; epidermis smooth, cells 25 40 ´ 20 25 µm, walls not to slightly thickened, trigones absent or small; oil cells few, scattered; air pores surrounded by 1 3 tiers of 4 6 scarcely differentiated cells; ventral scales purple with few scattered oil cells; appendages 1 2, white, lanceolate. Sexual condition paroecious, androecia of inconspicuous papillae at posterior base of gynoecial stalk; gynoecia in apical notch of main thalli; stalks naked, often purplish, 1 3 cm, without hairlike scales at bases or apices; carpocephala bell shaped, smooth, 3 4 mm across, lobes 3 4, short, directed downward; pseudoperianths white or purplish, conical, of 8 12 segments, connate at their apices, occasionally free with age. Sporophyte capsules pale yellowish brown; spores yellow, 85 100 µm; elaters yellowish brown, 2 spiral, 150- 250 µm.
Capsules mature Mar.--June. Soil over rock near streams; low elevations; Ont.; Que., Ala., Ark., Conn., D.C., Ga., Ill., Ind., Kans., Ky., La., Maine, Md., Mass., Miss., Mo., N.H., N.J., N.C., N.Y., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va.
This species is common in e North America extending westward to Kansas; it has not been found west of the 100th meridian.