The Botany of Iceland - 01.12.1928, Qupperneq 62

386
JOHS. BOYE PETERSEN
mens in each sample. The localities in which I found it were very
dissimilar, so that it is difficult to gain any idea of the conditions under
which it thrives best. The localities were: m\ri, naked ground, ground
with mosses, lilað (2 samples).
Anomoeoneis zellensis Grun. Cl. Syn. II, p. 7. V. Heurck, Syn.
Pl. 12. flg. 14.
E. Icel. 7.
Hardly an aérial alga. On the whole it is evidently rare in Iceland.
Frustulia Ag.
Frustulia vulgaris Thw. Cl. Syn. I, p. 122. Vanheurckia vulgaris
V. H. Syn. Pl. 17, íig. 6.
E. Icel. 123, L.? 125 — N. Icel. 217, 218.
The species is very common in fresh water in Iceland (Ostrup
116 samples). I have not been ahle to demonstrate with certainty the
presence of specimens with cell contents in any of the above-mentioned
samples. Hence it is hardly probahle that it is capable of living a terre-
strial life.
Stauroneis Ehrb.
Stauroneis agrestis Boye P. Boye Petersen 1915, p. 289, fig. 9.
E. Icel. 125 - N. Icel. L. 218.
In the two samples mentioned, there occurred very small Stauroneis
specimens which must be referred to the present species. One specimen
measured in 1. 24 /t, br. 4,6 ji, striæ very fine. Still smaller specimens
occurred in the samples.
Stauroneis anceps Ehrb. Cl. Syn. I, p. 147.
E. Icel. 123 — N. Icel. 140, 215.
This species is hardly an aérial alga. I found one large specimen
in sample 123 (1. 125 jx, hr. 23/r, str. 18 in 10/,«), and a smaller form in
sample 215, so small indeed that it approaches very near to S.agrestis
Boye P. It occurred among desiccated algæ in sample 140 derived from
a ditch.
Stauroneis lapidicola Boye P. n. sp.
Valva ovali-lanceolata, apicibus obtusis, iong. 6,6/«, lat. 3,1/t,
striis invisibilibus, stauro marginem attingente. Fig. 12.
Fig.^. N. Icel. 217.
btauroneis
lapicticola j have only seen two specimens of this small species,
BTxP12n00)' but they were so characteristic that I do not doubt that they
represent a species not hitherlo described. They were found
on a stone in »Stóra Gjá» near Mvvatn, among Prasiola crispa.