Hypnea spinella (C.Agardh) Kütz.

Description: Plants in cushionlike growths with individual erect branched axes poking up here and there, top of cushion thus irregular in outline, usually to 2.5 cm high. Axes cylindrical, less than 400 um diam. midway from base to apex, branches mostly dichotomous or irregularly divided. Secondary attachments frequent, if present, forming between branches in mid to upper parts of thallus. Short spinelike branchlets, variable in abundance, their bases somewhat truncated and apices sharply pointed. Tetrasporangial sori occasionally conspicuous on swollen tips of branchlets, but on same plant sori can also be found near the base, girdling branchlets.

Introduction and Origin: Native to Hawaii.

Hawaiian Distribution: Kauai, Maui, Oahu, Hawaii, Molokai

Habitat: Intertidal to subtidal, occasionally in turfs. In shallow, calm waters in the reef flat.

Environmental Effects: None documented. It is possible that, under favorable conditions, H. spinella may form dense floating masses as H. musciformis.

World Distribution: Type locality: West Indies. Caribbean to Brazil, Hawaiiand Islands, Micronesia, Philippines, Japan, Tahiti.

Commercial Interests: Edible species, sometimes found in poke (traditional Hawaiian food). It is commonly consumed (boiled in coconut milk) in Asia and the West Pacific.

Rate of Spread / Method: Growth rate unknown. Usually sterile, propagates mostly through fragmentation and vegetative growth.

Factors likely to influence Spread and Distribution: Relatively calm waters, high nutrients availability.

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

Control Methods: None used. Harvesting for food by community would likely decrease its abundance.

References: