54 



Veit Breciier Wittrock. 



Rhizoid part. The rhizoid, parted from the cauloi'd by the oblique wall 

 formed in the germination of the spore, consists in F htwehsis nob. as a rule of 

 one cell (pi. 2, tig. 1, 5, <>, 7 rh , pi. 4, fig. 4, 5 rh). Seldom it develops so as to 

 have several (up to 12) cells (pi. 4, fig G, 7). In this species I have not rarely 

 met with spores in the rhizoid also. PI. 4, fig. 9, 10 and 11 represent such spore- 

 carrying rhizoi'ds with different number of spores. In one case I have seen a rhizoid 

 with fully developed branches, consisting, however, each of but one cell. This rhi- 

 zoid is represented in pi. 4, fig. 8. Very seldom it happens that the rhizoid is 

 but rudimentary, being formed of only a very small process from the germinated 

 spore, which process has not been parted from the basal cell of the cauloi'd by a 

 cell-wall (pi. 1, tig. 8 rh, pi. 4, fig. 2, 3 rh). 



. Sterile specimens generally have a stronger ramification than the fertile 

 ones. The branches of the l:st degree are often formed two and two by the same 

 mother cell and are then placed opposite, or almost so, to each other (pi. 1, fig. 8, 

 lower part). Branches of the 2:d degree are not rare. The sterile specimens are 

 also greater in size than the fertile ; regarding this, see below 'in "Measurements,)) 

 Prolific cells (pi. 3, fig. 1 j>) occur in sterile specimens much oftener than in fer- 

 tile ones. 



Measurements. Fertile specimens. The greatest of these, that I have 

 seen, have had a length of 3 l / 2 centimeter; but generally the specimens are much 

 shorter. 



Cauloi'd part of the t hall us. The vegetative cells of the principal fila- 

 ment are on an a v. 59 ft thick; the smallest observed thickness is 45 fi and the 

 greatest 80 ii. Vegetative cells in the branches of the l:st degree are on an av. 

 45 /< thick; the limits of variation 38—51 /i. The cells in the branches of the 2:d 

 degree are in general 40 fx thick. The length of the vegetative cells varies very 

 considerably. In general they are 12 to 20 times as long as thick, but you also 

 find spore-carrying cells which are but little longer than the thickness; whilst cells, 

 particularly terminal, have also been observed # up to 30 or 40 times as long as 

 thick. — The terminal spores are on an av. 88 ,u thick and 21'.J (X long. The 

 limits of variation are indicated by the following numbers: t 1 h " 2 o5 255 225 ^ ne 

 inclosed spores have averaging a thickness of Si m and a length of 205 /t. They 

 vary between !*■ Jj> and ™ /i. The bigger spores belong of course to the principal 

 filament, and the smaller ones to the branches. The spore-membrane has in ripe 

 spores a thickness of 3 to 5 /.i, 



Rhizoid part. Its vegetative cell (or cells) is on an av. 42 /x thick. It 

 varies between 35 and 55 ,« The length exceeds the thickness 4 up to 40 times. 

 When spores occur in the rhizoid, they are on an av. 1 4 narrower than those in 

 the cauloi'd, but of about the same length. 



Sterile specimens. The dimensions are here generally somewhat larger. 

 Specimens of a length of 6 — 7 centimeter are not rare, and those of 4 — 5 cm. 

 seem to be the most common ones. The cells of the principal filament are on an 

 av. 80 /< thick; they vary between 50 and 110 ,</. The cells in the branches of 

 the l:st degree are averaging 57 ju in thickness. The limits of variation are 40 /.i 

 and 85 ff. Branches of the 2:d degree are on an av. 50 ^ thick. The length of 



