Fabronia Raddi, 1808

These are very small pleurocarps with elongate, thin-walled cells and with leaf margins dentate to ciliate.

Key to Fabronia

Species included are in Fabroniaceae:
Fabronia ciliaris (Bridel) Bridel
Fabronia pusilla Raddi

Fabronia is one of our smallest pleurocarpous mosses. It grows on tree trunks and on rock outcrops, often under overhangs. If one sees a very small prostrate and branched moss on such a substratum, one should look for the very long terminal cell of each leaf. Often additional cells are similarly elongate into ciliate marginal cells but the the single apical cell will define the plant. Fabronia has a rather silvery sheen upon close observation with a hand-lens. When growing among other mosses, Fabronia may be visible only when the goblet-shaped capsules emerge above associated plants.

A. Leaves dentate with the individual teeth composed of 0.75-2.0 cells .....Fabronia ciliaris
A. Leaves ciliate-dentate with the teeth composed of one or more very much elongate cells .....Fabronia pusilla