''Cryptomitrium tenerum'' is a species of

liverwort The Marchantiophyta () are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of ...

native to North America. It is the only representative of its genus on the continent.

Description

Like most other

Marchantiales Marchantiales is an order of thallose liverworts (also known as "complex thalloid liverworts") that includes species like '' Marchantia polymorpha'', a widespread plant often found beside rivers, and ''Lunularia cruciata'', a common and often tro ...

, it has a flat, dichotomously branched

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or " twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms ...

, which in this species is pale green, flattened, dichotomously branched, thin, and somewhat shiny, measuring 0.6 to 1.5 cm long, less than 1 cm wide. The thallus margins are brownish purple in patches and somewhat undulate, curling upward when dry. The dorsal surface has a faint pattern of irregular polygons, and around inconspicuous pores to the air chambers below. The ventral surface is dark purple, shiny towards the margins, and green medially. The ventral scales are small, dark, and purple, poorly developed at maturity. The peculiar oil bodies found in so many liverworts are found scattered throughout the thallus, ventral scales, and sporogonial receptacle. Cryptomitrium does not reproduce asexually via gemmae. It usually reaches its best development in February or March, depending on the amount and distribution of the winter rainfall. During the long rainless season the plants dry up, the tips reviving and giving rise to new plants with the advent of the autumn rains. Cryptomitrium tenerum Sporangiophore

Taxonomy

The species was originally named ''Marchantia tenerum'' by Hooker, but later placed in the genus ''Cryptomitrium'' by Austin before being revised into its current description by Underwood in 1884. The genus ''

Cryptomitrium ''Cryptomitrium'' is a genus of complex thalloid liverworts in the family Aytoniaceae. The genus name means “hidden turban” in reference to the inconspicuous sheath around the immature sporangium. Description Sporophyte bearing receptacl ...

'' is placed in the

Aytoniaceae Aytoniaceae is a family of liverworts in the order Marchantiales. Genera * '' Asterella'' Palisot De Beauvisage 1805 non Saccardo 1891 non Hara 1936 non Sollas 1886 * '' Cryptomitrium'' Austin ex Underwood 1884 * ''Mannia'' Corda 1829 * ''Plagio ...

with other liverworts with flat thalli and stalked receptacles, such as

Asterella ''Asterella'' is a liverwort genus in the family Aytoniaceae. Species A partial list of species includes: * ''Asterella australis'' (Hook.f. & Taylor) Verd. ex G.A.M.Scott & J.A.Bradshaw * '' Asterella bolanderi'', the Bolander's asterella * ...

, The genus name means “hidden turban” in reference to the inconspicuous sheath around the immature sporangium. The common name for ''Cryptomitrium tenerum'' is the flying saucer liverwort referring to the flat disc-shaped

sporangiophore {{Short pages monitor