Gymnogongrus griffithsiae

Gymnogongrus griffithsiae is a small uncommon seaweed.

Description

This small alga grows to 5 cm long from a small disc. The fronds are erect, stiff and branch dichotomously in 1 plane, the tips a little flattened. In colour it is dark purplish brown. The structure is multiaxial with elongated cells surrounded cortical cells.

Reproduction

Male spermatangia are unknown. Carpotetasporangial outgrowths, that is sporangia containing four spores, by a carposporophyte outgrowth which develops during the year.

Distribution

Found in Great Britain and Ireland with a southern range, as far north as Lough Swilly. In the north Atlantic in the Azores in Europe to Massachusetts to Virginia in North America.

Habitat

The plants grow in rock pools of the lower littoral and in the upper sublittoral.

Possible confusion

This species is similar to Ahnfeltia plicata which usually has wiry irregular branching.