The Botany of Iceland - 01.12.1928, Page 76

400
JOHS. BOYE PETERSEN
Navicula radiosa Kútz. Gl. Sjrn. II, p. 17. Van Heurck Syn. Pl. VII,
flg. 20.
N. Icel. 169.
This very common fresh water species (0strup 286 samples) can
hardly thrive on land, and as a malter of fact I found no specimens
with cell contents in the sarnple.
-----v. minutissima Grun. Cl. Syn. II, p. 17.
E. Icel. 125.
The specimen found had the following dimensions: L. 20 /r, br. 3,3 /i,
str.18 in 10/í,being thus in close agreement with Cleve’s description (l.c.).
— — var. tenella (Bréb.) Van Heurck. CI. Syn. II, p. 17. V. H.
Syn. Pl. VII, flg. 21-22. V. H. Types No. 107.
Vestmannaeyjar L. 399.
This variety comes very near to N. cincta var. Cari. In fact, I am
not sure that they can be kept distinct. According to Cleve and other
authors it is a form that thrives in quite fresh water. On the Vest-
mannaeyjar I found it in considerable quantity in a rocky cave at a
height of 20 m. There was plentj' of moisture present, so that its oc-
currence in tliis place does not warrant the assumption that it is a pro-
nounced aérial species.
Navicula viridula Kutz. Cl. Syn. II, p. 15. Van Heurck Syn. Pl. VII,
fig. 25.
N. Icel. 135?
Only a single specimen was observed. Its dimensions were: L. 79 /x,
br. 15 /a., str. 8 in 10 /i.
Pinnularia Ehrb.
Pinnularia appendiculata Ag. Cl. Syn. II, p. 75. Van Heurck Syn.
Pl. VI, fig. 18 and 20.
E. Icel. 123 — N. Icel. 217 - W. Icel. L. 338 — S. Icel. 295.
This species has long been known to be habitual among mosses,
on damp rocks, and in similar places (Cl. 1. c.). Ostrup found it in
Iceland in 19 samples from fresh water, hence it must be inferred that
it is no pronounced aérial alga. It was common in sample 338 which
was from the soil of a potato field near the hot springs by Helgavatn.
— — var. budensis Grun. Cl. Syn. II, p. 75. Van Heurck Syn.
Pl. VI, fig. 27, 28.
N. Icel. L. 133, 256.
This variety is chiefly known from hot springs. 0strup found it
in Iceland in 3 samples, 2 of which were from hot springs. None of the
2 samples in which I observed it was derived from the vicinity of hot springs.