Thalli comprising dorsiventral, attached crusts sometimes beset with protuberances,
or unattached subglobose masses. Crustose parts consisting of first-order filaments
(primigenous filaments) only (monomerous) or both first- and second-order filaments
(dimerous), the latter (postigenous filaments) at about right angles to the former.
First-order filaments either arranged in decumbent, arching tiers of cells (coaxial anatomy)
or curving upward toward the thallus surface (plumose anatomy). Cells in first-order filaments
rarely stratified and elongated (palisade cells). Outermost walls of epithallial cells rounded
or flattened, not flared. Cells in contiguous filaments often joined by secondary pit-connections;
cell fusions absent. Trichocytes present or absent, but if present occurring singly.

 

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