502 
doubt referable to this species, though no specimens from the 
Faeroes are to be found in his herbarium. He writes with reference 
to it (Hydrophyt., p. 145): — »Habitat ad littora Fseroensia, saxis 
maritimis in summo refluxus limite adnata, copiose«. Rostrup 
(1. c. p. 88) calls it Hormiscia penicilliformis (Roth) 
Fr. on the faith of Lyngbye’s record, and finally 
Simmons (1. c. p.274) calls it Ulothrix isogona 
(Engl. Bot.) Tliur. and records it as probably 
fairly common without, however, naming the 
habitat. 
s? 
181. U. Wormskioldii (Mert.) Rosenv., Gronl. 
Havalg., p. 920; Chaetomorpha Wormskioldii 
Kjellm., N. I., p. 384 (313). 
The base of this species — fig. 101 shows 
the lower part of a young plant — consists of 
a more or less large disc formed by numerous 
intertwined rhizoids, which spring from a fairly 
considerable number of cells situated in the ba¬ 
sal portion of the plant, these rhizoids grow 
downwards along the cell-wall, attaching them¬ 
selves to the sides of the filament. The single 
cells in the portion of the filament thus covered 
by the rhizoids are on the whole distinctly dis- 
cernable right down to the base. These rhizoids 
closely resemble the extracellular rhizoids of 
U. mirabilis , but the intracellular rhizoids of the 
latter are wanting in U. Wormskioldii. 
The chromatophore, as found in a well- 
developed cell, has the shape of a very richly 
and finely reticulated parietal plate, with nu¬ 
merous small pyrenoids, and in a young cell 
it occurs as an almost unperforated plate or 
with a very few holes only, and fewer pyrenoids. The chromatophore 
of U. mirabilis is more dense and of a darker colour and has com¬ 
paratively few, but larger pyrenoids. Wille’s figure (77 a) in his 
synopsis of the Chlorophycece in Engler und Prantl: »Die natur- 
lichen Pflanzenfamilien« gives a good representation of a young 
cell; in older more developed cells of U. mirabilis the chromato¬ 
phore is richly perforated and is almost quite reticular. 
Fig'. 101. Urospora Wormskioldii 
(Mert.) Rosenv. Base of plant 
with numerous downward 
growing' rhizoids. 40: 1. 
I 
