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Order Halymeniales

Family Halymeniaceae

Genus Prionitis J.G.Agardh

Thalli erect, one to several cylindrical to subcylindrical upright arising from a discoid holdfast, dichotomously or irregularly branched, surfaces of uprights smooth or knobbly, . Structure multiaxial: medulla of densely interwoven longitudinal filaments; cortex of compact, branched anticlinal filaments of cells decreasing in size towards the surface. Sporophytes and gametophytes isomorphic. Tetrasporangia embedded beneath thallus surface, cruciately divided; gametophytes dioecious, cystocarps embedded within thallus, surrounded by envelope of interwoven filaments, ostiolate.

The genus comprises 19 currently recognised species, distributed mainly in the temperate north Pacific (Guiry MD in Guiry & Guiry 2017) .

Key to the species


1a. Uprights uniformly slender (about 1 mm diameter) smooth

Prionitis filiformis

1b. Uprights increasing in diameter distally (to up to 6 mm), knobbly and distorted

Prionitis nodifera


References Prionitis

Guiry, M.D. in Guiry, M.D. & Guiry, G.M. 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 23 May 2017.


Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town,; Accessed on 02 March 2024.