Dendroceros spp.


Species of Dendroceros are typically distributed across all the major continents in tropical and subtropical regions, living epiphytically on substrates.


Overall Structure:

Dendroceros spp. are annual or perennial.  The gametophyte has a somewhat ribbon-shaped growth form.  The deeply lobed thallus gives the illusion there are irregular-shaped leaves attached to the midrib.

Thallus Structure:

The midrib is swollen and may look similar to a stem with two rows or lateral, irregularly-shaped leaves.  The lateral wings are unistratose.

Within the lateral wings of the thallus are pore-like mucilage clefts which house Nostoc algal colonies. There are no stomata.  The cells of the thallus are thin-walled, and the central cells of the stem have pitted walls, similar to groups of hepatic liverworts. Further, there are internal cells with band-like wall thickenings where future archegonia and sporophytes develop.

The chloroplast structure differs from other hornwort groups and aids in phylogenic classification.  The chloroplasts are large and star-shaped.  Pyrenoids are present in the chloroplasts, are spherical, and are surrounded by starch.


The rhizoids are located on the ventral surface of the thallus and are unicellular and smooth.  The rhizoids may originate from surface cells after periclinal division of epidermal cells.


The sporophyte has 2 lines of dehiscence. There are spiral thickenings on the outer cells of the columella and on the inner cells of the sporangial jacket. Elongate psuedo-elators aid in the dispersion of spores.

Endosporic germination of spores occurs before sporophyte dehiscence.  Multicellular spores are released and develop into new gametophytic generations upon contact with a substrate.