The Botany of Iceland - 01.12.1928, Side 106

430
JOHS. BOYE PETERSEN
Dactylococcus caudatus var. bicaudatus Hansgirg 1887, p. 86, Hans-
girg 1886, p. 14.
Ourococcús bicaudatus Grobéty 1909, p. 357.
Keratococcus caudatus Pascher Susswasserflora Heft. 5, 1915, p. 217.
E. Icel. 61.
The genus Dactylococcus was established in 1849 by Nageli (Gatt.
einzell. Algen p. 85) with the species D. irifusionum. Grintzesco main-
tained (1902) that D. infusionum is a form of Scenedesmus acutus Meyen.
Though I have my doubts ahout the correctness of Grintzesco’s iden-
tification of the alga cultivated by him with Dactylococcus infusionum
Nág. (cf. Boye Petersen 1915, p. 332), I consider it riglit to give D. bi-
caudatus a new generic name as attempted hy Grobéty (1. c.). Unfortunately
• the name she selected had already with a slight difl'erence in the spelling
heen employed for another alga, so Pascher gave the genus a third
name Keratococcus (1. c.). Curiously enough Pascher on that occasion
rejected the oldest specific name, viz. bicaudatus A. Br. from 1868, substi-
tuting caudatus Hansg. froni 1886, and was therein followed by Puymaly
1924, p. 219. I consider this incorrect, so I have revived the earlier
name. Md. Grobéty has shown (I. c.) that D. caudatus Hansg. and D.bi-
caudatus A. Br. are identical, the cells in the species having now two,
now one elongation. Without knowing Md. Grobéty’s work I have
ascertained the same fact by observing the multiplication of a single
cell. (1915, p. 332, Tavle II, fig. 34 a. b).
Hansgirg had without ceremony reduced the name bicaudatus to
that of a variety (1. c.) under a new species D. caudatus. As the author
of the species he put Reinsch in brackets, it is true, but evidently
this does not mean that that author called the species caudatus but
referred it to another genus, as it would mean according to modern
usage. It appears plainly enough from Hansgirg’s own statement
(1887, p. 86) that lie only means that Reinsch was the flrst to observe
and figure the form with only one elongation (sub nomine Characium
pyriforme).
In Iceland I have only found the species in few specimens on soil
by the roadside near Hallormstaðir among mosses and Protonema.
In Denmark I have found the species on earth, granite, walls, bark,
thatched roofs, and old Polypori (Boye P. 1915, p. 333). Puymaly
most frequently found it on the last substratum, and on rotten wood
and straw (1924, p. 223).
Oocystis rupestris Kirchn. Printz 1913, p. 174, Tab. IV, flg. 7—9.
Wiltr. et Nordst. Alg. exsicc. No. 725.
S. Icel. 352.
On the lower damp part of the Sæluhús (travellers’ shelter) on
Mosfellsheiði I found an Oocystis which I refer with some doubt to the
present species. The cells were 30 p long, 12 /u broad, furnished with 1
chromatophore with a distinct pyrenoid surrounded by starch. However,
the cells diífered from the typical 0. rupestris by the wall as a rule
showing a rather distinct thickening at one pole.
0. rupestris is one of the species that thrive well on damp rocks.