Liverworts can be broadly separated into two distinct artificial groups: leafy and thalloid. Bazzania trilobata is an example of a leafy liverwort. Though they look like mosses and have a similar life cycle, leafy liverworts have important morphological differences that set them apart. For example, liverwort leaves are often in two lateral ranks with a third row of smaller leaves on the back of the stem, while moss leaves have a spiral arrangement (Vitt et al’s Mosses, Lichens & Ferns of Northwest North America (1988)).
Bazzania trilobata grows in “large clumps or dense widespread mats on boggy soils, forest ground, rotten logs, and at the bases of trees especially in cedar swamps and hemlock or boreal forests”. It is difficult to track down a precise distribution for the species, but it has been observed in northern temperate forests at a minimum. Generally, Bazzania species are more typical of tropical environments, though they grow in a wide range of climatic conditions, only excluding deserts and the poles (Schofield’s Field Guide to Liverwort Genera of Pacific Northwest America (2002)).
The leaf orientation of Bazzania trilobata is worth noting, as it is the opposite of most liverworts. As seen in the close-up photo, the upper edges of this species’ leaves overlap the lower edges of the leaves above them. This is described as an incubous leaf arrangement. The majority of leafy liverworts have the opposite arrangement, succubous, where the lower edges of the leaves overlap the upper edges of the leaves below them.