The
epiphytic and
epiphyllous Dendroceros is the only
desiccation-tolerant hornwort genus. The
gametophyte is yellowish-green and usually less than one-half cm wide. The
thallus branches in a bifurcating pattern. In the subgenus
Apoceros, there are cavities in the central strand of the thallus. The edges of the thallus are only a single layer of cells thick and have an undulating margin. It is common to find symbiotic colonies of
blue-green bacteria (usually
Nostoc) growing among the cells. Under a microscope, the epidermal cells have
trigones. The
sporophyte is erect when mature, growing up to 5 cm tall. Unlike many hornworts, the surface of the
Dendroceros sporophyte lacks
stomata, as do the sporophytes of the related genera
Megaceros and
Nothoceros. The interior of the sporophyte differentiates into a central column and a surrounding mass of
spores and
elater cells, with a distinct spiral. The spores are green and multicellular with an ornamented surface. ==Classification==