Neosiphonia sphaerocarpa

Thallus fine filamentous, bushy, to 2 cm high, light reddish-brown. Branching mainly alternate or irregularly dichotomous. Branches narrowly angled, 80-100 μm diam., gradually tapering to apices. Prostrate axis 150-195 μm diam.; erect axes 60-165 μm diam., of four pericentral cells, Cortication absent. Trichoblasts 3-4 times dichotomously branched. Tetrasporangia spherical, (50-)60-75 μm diam., tetrahedrally divided, in spiral series. Spermatangial branchlets stalked, cylindrical, 37.5-60 μm diam., 150-250 μm long, Cystocarps spherical, 200-320 μm diam. with wide ostiole. Attachment by unicellular rhizoids pit connected to pericentral cell. Growing on hard substrate or epiphytic on larger algae.

Subtropics, tropics of Atlantic, Indian and Pacific Oceans.