Gymnogongrus griffithsiae is a small uncommon seaweed.
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.[1] [2]
Male spermatangia are unknown.[2] [3] Carpotetasporangial outgrowths, that is sporangia containing four spores,[4] by a carposporophyte outgrowth which develops during the year.[2]
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.[5] [6]
The plants grow in rock pools of the lower littoral and in the upper sublittoral.[2]
This species is similar to Ahnfeltia plicata which usually has wiry irregular branching.[2]
Guiry, M.D., Irvine, L.M., Morton, O. 1981. Notes on Irish marine algae- 4 Gymnogongrus devoniensis (Greville) Schotter (Rhodophyta. Irish Naturalists Journal 20: 288 - 292.