Plants green above with deep purple pigmentation along margins and below; branching intercalary from a simple or dichotomous main thallus; lateral ventral branches frequent, arising by narrow stalks, the distal portions often obcordate; apical innovations also occur. Thalli 10 30 ´ 2 3 mm with margins often undulating and ascending; epidermis smooth, cells 30 50 ´ 30 35 µm with slightly thickened walls, without distinct trigones; air pores surrounded by 1 2 tiers of 6 8 cells; ventral scales deep purple with scattered oil cells; appendages 1 2, white or purplish tinged, subulate to acuminate, 3 4 cells wide, slightly narrowed at base. Sexual condition autoecious, male branches short, obcordate, sometimes innovating apically; androecia terminal, deep purple, oblong, ovate or subcordate, thickened, the margins with small subulate scales; gynoecia on principal branches or short innovative branches; stalks 0.5 1.5 cm, reddish tinged with hairlike scales at apices and sparse scales at bases; carpocephala domed, 2 3 mm wide with conspicuous finger like tubercules on upper surfaces, 1 3 lobed below; pseudoperianths white to slightly purple, of 8 10 segments, connate at apices. Sporophyte capsules brownish; spores yellowish to pale brown, 60 100 µm, elaters brown, 1 2 spiral, 140 200 µm.

Capsules mature May. Soil over rocks, often calcareous, near streams; Tex.; Mexico.

The conspicuous finger like tubercules on carpocephala distinguish this species from others in the flora. Asterella echinella was listed by W. S. Sullivant (1856) and L. M. Underwood (1884) as A. elegans, a plant of Mexico. Subsequently R. Stotler and B. Crandall-Stotler (1977) listed it as A. elegans subsp. echinella (Gottsche) Del Rosario in error. Thus far, A. elegans has not been found north of Mexico.