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Lyngbya majuscula

(Dillwyn) Harvey 1833: 370


Thallus: filamentous, forming tangled masses, to 50 cm long, generally shorter, brown-green, yellow-green, black-green to black-purple. Trichomes long, straight or curved, rarely coiled, 30-90 µm diam. Cells disc-shaped, (16-)35-45(-80) µm diam., 2-4 µm long; not constricted at cross walls; end cell somewhat rounded or dome-shaped, not tapering, cap absent; cell contents finely granular, dull green, blue-green to gray. Sheaths layered, colorless, 4-11 µm thick. Heterocysts absent.


Common: initially epiphytic on seagrasses; most visible forming large mats in calm waters or unattached as free-floating, black, hair-like mats; poisonous to mammals; causing swimmer's itch reaction in humans; intertidal to 2 m deep.


Pacific Mexico, Pacific Panama - New record for Panama.

Type Information:

Lectotype locality: England


Major Group: Cyanobacteria - Class: Cyanophyceae - Order: Oscillatoriales - Family: Oscillatoriaceae