Mindeskrift for J. Steenstrup. XXXII. 



This species is very common along the shores of the islands and occurs in exposed 

 or sheltered piaces. In exposed localities, where the sea constantly splashes the rocks 

 Sargassum vulgare is able to thrive above the surface; in the more sheltered piaces it 

 occurs close to the surface, or a little below. 



Sargassum vulgare is the dominant species in the Sargassum-ye^QloXion forming 

 with Turhinaria trialata a vegetation of large, brown algæ corresponding with the 

 Fucaceæ-Association in northern seas. 



Geogr. Distrib. This species is said to occur 

 at nearly all subtropical and tropical shores of the At- 

 lantic Ocean: America and the West Indies, Africa, 

 Spain etc. 



2. Sargassum londigorum (L.) Kiitz. 



KuTZFNG, Species Algarum, p. 612. 



— , Tabulæ Phycologicæ, vol. XI, tab. 19, fig. II. 

 J. Agardh, Species Sargassorum Austral., p. 110. 

 Fucus lendigeius L., Species plant., p. 1628. 

 Turner, Fuci, p. 107, tab. 48. 



The specimens which I have referred to this 

 species possess leaves with a distinct midrib and 

 small, most often scattered cryptostomata; these 

 are, sometimes, arranged more or less regularly 

 in a single series on both sides of the midrib. 



The basal leaves are more or less dentate; 

 the superior have a somewhat sinuate to entire 

 margin. 



The leaves are linear-elliptic 4 — 5 mm. broad, 

 and until 3 cm. long, with a short stalk or ses- 

 sile. The vesicles are scarce, often quite absent; 

 when present, according to my observations, they 

 occur only at the upper end of the branch; they 

 reach the size of a small pea, and are often 

 somewhat oval, now and then provided with a small, leaf-like prolongation at their apex. 

 The receptacles are mostly aggregated at the upper end of the branches; they are 

 cylindric and irregularly branched. 



This species appears to be closely related to Sargassum vulgare, representing prob- 

 ably a mere variety of it. 



St. Thomas: Store Nordside Bugt, growing in a rather exposed place. 

 Geogr. Distrib: West Indies, Bermuda, Teneriffa etc. 



Fig. 1. Sargassum vulgare C. Ag. Part of a 

 plant with receptacles and vesicles. ( A litle 

 over natural size, about Ve magnified). 



