Bornetella oligospora

Thallus erect, subcylindrical to clavate or slightly curved, gregarious (forming extensive colonies), bright green, shining, slightly calcified, (0.7)-1.4-4.0 cm high, 3.5-6 mm diam. in upper part and tapering to the base to 2 mm. Inner structure: central axis bearing 24-32 primary branches. The primary branches bear 4-6 short capitate secondary branches joined together and forming a monostromatic cortex consisting of polygonal cells (in surface view), 180-200(-340) mm across. Aplanosporangia (four or more on primary branch) spherical, 150-220(-250) mm, on a short stalk, separated by doubled wall, attaching laterally to the primary branches and containing 6-9 aplanospores. The aplanospores oval, sometimes spherical (75-85 mm diam.) or ellipsoidal, (85)-105-120×70-80(-90) mm. Holdfast small, disc-like. Growing on stones, dead corals, in upper intertidal to upper subtidal (to 15 m deep), in protected areas.

Subtropical and tropical waters of Indian and Pacific Oceans.