Ulva rugosa Linnaeus, Mantissa Plantarum Altera: 311. 1771.

"Habitat ad Cap. b. spei. Koenig. 39." RCN: 8365.

Type not designated.

Original material: Herb. Linn. No. 1275.9 (LINN); König 39, Herb. Linn. No. 1275.31, lower right specimen (LINN); König s.n., Herb. Linn. No. 1275.8, left specimen (LINN) .

Current name: Splachnidium rugosum (L.) Grev. ( Splachnidiaceae).

Note: Unusually, there is a syntype ( König 39, 1275.31 LINN) in existence for this name but, unfortunately, its identity does not correspond with the generally accepted usage of S. rugosum (L.) Grev. Ulva rugosa may therefore prove to be a candidate for conservation (see Spencer & al. in Taxon, in press).