The Botany of Iceland - 01.12.1928, Side 100

424
JOHS. BOYE PETERSEN
comijxa dispar and C.Naegeliana distinct. In grovvths of these plants I
have often found it very difficult to ascertain whether or not pyrenoid
was present, and one gets the impression that the pyrenoid may be
entirely absent, e. g. in young cells, even if it is quite plainly present
in older cells of the same species. Hence I think that one should not
attach too much importance to this character.
Puj'maly (1. c.) would identify Gloeocyslis vesiculosa Nag. which is
the type of the genus with Coccomyxa Naegeliana (Art.) Wille, 1) because,
according to Nágeli’s own statement, it has been found growing on
damp beams and stones, 2) because he thinks he can demontrate from
the figures (Nageli 1849 Taf. IV F) that the cells do not multiply by
siinple cell division in three directions but by autospore formation. If
these considerations are correct, since stratified and »eingeschachtelten«
gelatinous sheaths are not unknown in the true Coccomyxa species
(C. Corbierei Wille 1910, p. 302), it is no longer possible to íind any
decisive difference between the two genera. Puymaly’s explanation
does not, however, seem to me quite convincing. If it is really Coc-
comyxa Naegeliana Naegeli has described, it is incomprehensible that he
should have drawn only round cells, the great majority of the cells in
this species being oblong or fusifortn, neither does Puymaly’s assertion
that reproduction in G. vesiculosa is an autospore formation seem to me
convincing. No original specimen of Nðgeli’s plant being probably in
existence, it will be impossible to get to the bottom of the matter, hence
I am of opinion that we rnust for the present maintain tlie generic
name Coccomyxa for the following more closely investigated species:
C. Naegeliana (Art.) Wille, C.dispar Sehmidle, C. Corbierei Wille, C.litlo-
ralis (Hansg.) Wille, C. nalans (Chod.) Schmidle. Common to all these
species are the often oblong cells, though spherical cells may quite
occasionally be found. Possibly there exist true Gloeocystis species with
a stratiíied gelatinous sheath and simple cell-division in three directions
in accord with Nágeli’s diagnosis. To these perhaps belong e. g. C. oli-
vacea Boye P. (1914, p. 324) and Gloecystis gigas (Kutz.) Lagerh.
Printz is evidently of the same opinion, for in Engler et Prantl,
Die natúrlichen Pflanzenfamilien 2. Aufl. he refers the two genera to
diflerent families, viz. Gloeocystis to Tetrasporaceœ and Coccomyxa to
Pleu rococcaceœ.
Coccomyxa dispar Schmidle. Schmidle 1901, p. 20, Tab. I, íig. 6—25.
Boye Petersen 1915 p. 323.
S. Icel. 276.
The spccies was originally found by Schmidle on mosses in pine
forests. I myself have observed it on very diverse substrata in Denmark,
thus on mosses in bogs, on rocks, stumps of trees, bark, and soil. In
Iceland I found it on a paling in Reykjavík.
Apatococcus lobatus (Chod.) Boye P. n. comb. Pleurococcus lobatus
Chodat 1902, p. 284, lig. 199. Boye P. 1915, p. 321, Tab. I, lig. 5—10.
Pleurastrum lobatum Printz 1921, p. 21, Pl. VI, fig. 156—200. Apatococcus
vulgaris Brand 1925, p. 348, fig. 40—53.
S. Icel. 276, 286.