106 M. FOSLIE. [1905 



carps. They may sometimes be confounded, when M. Lejolisii 

 is growing over L. membranaceum or a new crust of the latter 

 species is partly extending over an older one so as to give the 

 alga a somewhat solid appearance. The structure, however, of 

 these two species is different. Among recent authors who seem 

 to have referred forms of M. Lejolisii to L. membranaceum, I will 

 mention Mr. Kleen 1. c, being of interest from a phytogeographical 

 point of view. Unfortunately there is, according to the liberal 

 communications of Professor Kj ell man, found no specimen in 

 his herbarium. He declares, however, 1. c. that the species grows 

 on Fucus vesiculosus f. vadorum. As far as I have seen, L. mem- 

 branaceum does not occur, on Fucus, while, on the contrary, this 

 is often the case with M* Lejolisii and Lithoph. macrocarpum 

 in northern areas. Both the species last mentioned, besides, appear 

 to be dispersed more to the north than L. membranaceum. 



As to host plant, M. Lejolisii is somewhat more circumscribed 

 than M. farinosa, as it does not occur on so many different plants 

 as the latter. This is, however, only in part due to the fact that 

 its area is smaller. It occurs most frequently in northern areas, 

 where it often takes the place of M. farinosa, e. g. on Zostera. 

 It appears particularly growing on this plant. But it is also found 

 on the leaf of Laminaria, on Chondrus, Oigartina, Furcellaria, 

 Fucus and others. On the coast of Denmark it has even been 

 found scantily and feebly developed on Ruppia. Besides it seems 

 to be a form of this species which scantily occurs on Corallina 

 rubens at Alger (Debr ay !). The cells of the latter are small with 

 minute cortical cells. The conceptacles are about 140 /J- in dia- 

 meter and are in shape approaching partly those of M. farinosa, 

 partly those of typical M. Lejolisii. A similar form occurring on 

 Folysiphonia violacea has been collected to the south east of 

 Bragerne in the Skager Rack (Rosenvinge!). It forms minute 

 crusts on the branches, sometimes surrounding a part of a branch, 

 or extending over two branches closely connected, occasionally 

 even covering parts of the cystocarps of the said host. The crusts 

 are always less than 1 mm. in diameter or in length. The alga 

 is scantily provided with conceptacles (of cystocarps?), which are 



