The
spores are dark gray, dark brown or black. This distinguishes it from the related genus
Phaeoceros, which produces yellow spores. The
thallus lacks air chambers and scales, and has no well defined mid rib. It has unicellular smooth rhizoids in the ventral region. It is irregularly lobed, and exhibits rare dichotomous branching. The thallus has little to no tissue differentiation, being composed of thin, compactly arranged uniform
parenchymatous cells.
Anthoceros species are host to species of
Nostoc, a symbiotic relationship in which
Nostoc provides nitrogen to its host through cells known as
heterocysts, and which are able to carry out photosynthesis. The
Nostoc colonies are present on the lower ventral surface. They often grow in slime pores, mucilaginous groups of decomposed cells within the plant which open outward through a pore guarded by 2 cells.
Nostoc colonies are visible as blue-green patches on the plant body. The plants grow in moist clay soils on hills, in ditches, and in damp hollows among rocks. == Reproduction ==