Thalli polysiphonous, uncorticated, with indeterminate growth in prostrate system which exogenously produces upright determinate branches in no special pattern. Trichoblasts non-emergent in prostrate system, spirally produced, one on each segment; erect polysiphonous branches develop from some of the dorsal trichoblasts; upright branches with emergent trichoblasts that may be branched and spirally arranged on the axis. Polysiphonous branches on erect system often absent but, when present, in irregular positions. Rhizoids on ventral side of prostrate branches, cut off from pericentrals and producing multicellular thigmotactic tips. Chloroplasts often in transverse positions in pericentral cells. Reproductive structures borne on upright branches. Tetrasporangia in distal spiral series, one per segment. Cystocarps and spermatangial capitula near distal ends of branches. Male capitula replacing trichoblasts and having sterile tips. Cystocarps ovoid to urceolate, with an ostiole.

After M. Guiry, Algaebase 2014

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