56 



Veit Brecher Wittrock. 



the branches of the 2:d degree, but also with those of the 3:rd (pi. 6, fig. 4). — 

 The attaching points of the branches on their supporting cells are the same as in 

 P. kewensis nob. The length of that piece of the supporting cell which is situated 

 above the attaching point of the branch is in general equal to the diameter of the 

 branch. 



The subsporal cells are in this species uncommonly productive. Very often 

 we find that a subsporal cell has brought forth one subsporal branch, and now 

 and then it even happens that such a cell has formed two (opposite) branches (pi. 

 6, fig. 5 bs). In one case I have observed that a subsporal cell, whose mother- 

 cell has brought forth not only one spore but a pair of spores, has still had so 

 much living substance left that it has been able to form a subsporal branch, how- 

 ever small; see pi. 6, fig. 4 bs-. Subsporal branches exist of all degrees, of the 

 3:rd as well as of the l:st and 2:d (pi. 6, fig. 4 ha' 1 , bt> 3 ). As to the direction of 

 the subsporal branches in relation to their supporting cells (the subsporal cells), 

 a deviation here takes place from what is the case with the common, not subsporal 

 branches. The subsporal branches form, as a rule, a greater angle (of 50 and even 

 90 degrees) against their supporting cells, than the common branches (the angle of 

 these being, as in the other species of Pithophora, generally 45 degrees) The sub- 

 sporal branches are also placed somewhat farther below the top of their supporting 

 cells than the common branches. Neither are accessorial branches rare. They 

 proceed from a. point near the base of their mother cells (see pi. 6, fig 4 ac), thus 

 being analogous to the cauloid rhizine branches so common in Cladophor( ce (compare 

 parag. 5, page 36). 



In this species occurs a kind of branch formation which I have not observed in any 

 other species of Pithophora. Real spores, brought forth in the normal manner and remain- 

 ing attached to the mother specimen, do here sometimes form branches, instead of 

 germinating in the common manner after having separated themselves from the 

 mother plant. PI. 6, fig. (5 shows the uppermost end of a specimen in which a 

 number of spores have proceeded in this manner. We find there that the spores of 

 this species can, as well as the common vegetative cells, form one or two branches 

 each, and that the spore branches are formed from the side of the spores in a 

 manner in all the principal points resembling that in which normal branches are 

 formed from common vegetative cells. It is particularly remarkable that the spore 

 branches proceed from the very midst of the spore, and especially that the branches 

 have a position relative to the longitudinal axis of the spore which differs from 

 that which common normal branches have to their supporting cells. Instead 

 of forming an angle of only 45 degrees against the upper part of the supporting 

 cell (here the spore), they form an angle which is much greater, sometimes even 

 more than twice as great; see pi. 6, fig. f5. A parting-wall between the spore 

 itself and its branch-process has not been formed in the specimen represented by 

 this figure, but in other specimens I have observed one; see pi. 6, fig. 4 bsp. 



The spores are developed partly in the*prineipal filament and partly in the 

 branches of the l:st and 2:d degree (pi. (>, figs. 3, 4). In the branches of the 3:rd 

 degree I have never observed spores. Both the terminal cells and the inclosed 

 develop spores. The inclosed spores are almost purely cask-shaped; the terminal 



