A Grammatical Dictionary of Botanical Latin

thallosus,-a,-um (adj.A): pertaining to a thallus; thallose, flat, scarcely differentiated; also cordate, rounded or ribbonlike in form when in reference to liverworts and protonemata of Sphagnum and Andreaea in mosses; (in bryophytes) “of or pertaining to a thallus; often used in conjunction with a prothallial sporeling” (Magill 1990); = thalloideus,-a,-um (adj.A); cf. foliaceous, frondose;

- plantae thallosae, parvae, terrestres, raro natantes, carnosae, repentes, dichotome-ramosae, interdum ramulos adventivos e centr proferentes (Steph., of the genus Riccia), plants thallose, small, terrestrial, rarely floating, fleshy, creeping, dichotomously branched, someimes bringing out adventive branches from the center.

In liverworts, the vegetation may be divided into two groups: thallose and leafy liverworts. In older texts the thallose liverworts were called “frondose” and the leafy ones “foliaceous;” as by Sullivant (1856):

1. Vegetation frondose (stem and leaves confluent in a frond) [genera such as Marchantia, Metzgeria, Anthoceros]

2. Vegetation foliaceous (leaves and stem distinct) [genera such as Lophocolea, Jungermannia, Chiloscyphus].