Tuomeya americana (Kuetzing) Papenfuss

    Thalli up to 3.5 cm in height and mature filaments 315 µm in width, thallus attached by a small pseudoparenchymatous disc and rhizoids arise from base of the filaments. Thallus profusely branched; branching irregular; branches forming acute angles. Nodes and internodes indistinct macroscopically. Axial filaments covered by 2-3 layers of corticating filaments. A prominent apical cell observed only in young actively growing branch tips. Apical cells measure 5-9 µm in length and 7-13µm in width. Peripheral cells 6-7, each producing 3 primary laterals of limited growth. Each primary lateral 5-7 cells in height; cells 8-21 µm in length and 6-10 µm in width.

    Axial row of cells measures 65-210 µm in length and 36-70 µm in width. Peripheral cells produce corticating filaments, which surround the axial row of cells. Secondary laterals produced from corticating filaments, branching dichotomously or rarely trichotomously, up to 3 order. Cells of corticating threads measure 9-36 µm X 8-18 µm. Cells of secondary laterals measure 9-21 µm X 4-10 µm. Development of corticating threads and the formation of secondary laterals from them give pseudo-parenchymatous structure at mature regions of the thallus.