Asparagopsis armata Harvey
Also known as Falkenbergia rufolanosa Harvey
Common names: Harpoon Weed
Description: Gametophyte plants occurring from June or
July - August or September (sometimes overwintering), pale
purplish-red, quickly degenerating when removed from the water
and becoming distinctly orange; fronds bushy, with a cylindrical
axis to1 mm wide and 200 mm long, arising from bare, creeping
stolons; irregularly branched, with 4 rows of branchlets,
simple, short, branchlets alternating with longer ones with 4
rows of simple filamentous ramuli. Lower branchlets unbranched,
long, tapered, with harpoon-like barbs. Tetrapsorophyte
(Falkenbergia-phase) occurring all year round, but most obvious
in October-March, brownish-red, much branched, filamentous, in
dense cotton-wool-like tufts to 15 mm in diameter.
Habitat: Both phases readily reproduce vegetatively.
Drift specimens of gametophyte readily attach to other algae by
barbed branchlets, and produce new shoots. Introduced from the
Southern Hemisphere, the gametophyte was first recorded in
Europe in 1925 (Cherbourg and Biarritz), arriving in the British
Isles at Galway in 1941, and is now well established in open
sandy pools of lower intertidal and subtidal, on rock or
epiphytic (mainly on Ulva spp.) in the Channel Is, S
England (Swanage to Scilly Is.) and S and W Ireland (Carnsore
Pt, Co. Wexford; Magharees Lagoon, Co. Kerry; and from
Finavarra, Co. Clare north to Clare I., Co. Mayo).
Tetrasporophytes (Falkenbergia -phase) are epiphytic,
especially on
Corallina officinalis, in similar habitats to gametophyte, but more widely
distributed on western and southern coast N to Shetland Is.
Similar species: Bonnemaisonia hamifera occurs in
similar habitats but has crozier-shaped attachment branchlets
rather than recurved barbs.
Key characteristics: The harpoon-like hooks and bushy
habit are unmistakable; association with
Ulva rigida and similar
species.
Identification guide for selected marine non-native species (National Museum Wales). (Download free PDF, about 3.5 Mb).
Link:
Algaebase
Photographs © M.D. Guiry
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