Neosiphonia tongatensis (Harvey ex Kütz.) M.S.Kim & I.K.Lee

Description: Plants tufted, to 8 cm tall, reddish brown, soft to slippery, attached by numerous short, tufted rhizoids at bases of erect filaments. Filaments branched, with 4 pericentral cells, not corticated. Branching pseudodichotomous. Erect axes repeatedly branched from near base to mid levels, upper dichotomies elongate, fewer than below. Trichoblasts branched 2-3 times, attached in one-fourth spiral counterclockwise, soon deciduous, scar cells of moderate size. Mid portions of plants to 180 um diam., 2-2.5 times longer than wide. Tetrasporangia 40-80 um diam., forming short spiral series in main axes and laterals. Spermatangial heads formed on basal cells of trichoblasts, 25-50 um wide by 90-200 um long with or without single sterile cell. Cystocarps ovoid to obovate when young, later becoming more rounded.

Introduction and Origin: Native to Hawaii (Chamberlain 1881, Abbott 1947).

Hawaiian Distribution: Maui

Habitat: Quiet ponds, lagoons, brackish water to 22 ppt salinity. On sticks, pebbles, shells, rarely epiphytic on aquatic phanerogams.

Environmental Effects: Not studied. May affect recruitment of other species by successfully competing for substrate.

World Distribution: Type locality: Tonga. Hawaiian islands, Tahiti, Philippines

Commercial Interests: None.

Rate of Spread / Method: Growth rate unknown. Propagates through tetraspores, carpospores, and possibly by fragmentation.

Factors likely to influence Spread and Distribution: High nutrients availability.

Reasons for Success: Rapid growth rate, high nutrients availability.

Control Methods: None used.

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