326 



Dansk Botanisk Arkiv. Bd. 3. Xr. 1. 



softer consistence. The ramification of the branches is scarcer, the 

 branches are slender with thinner and longer cells ; the unbranched 

 summit of the first branch in the branch-system is especially much 

 elongated. In the basal part of the monosiphonous ends of these 

 branches the cells are about 40 n thick and their length about 70 |li. 

 Towards the top the cells become somewhat longer (about 120 ^), 



tapering at the same 

 time evenly to the 

 summit where the 

 breadth is about 25 

 |lI. The uppermost 

 end of the filaments 

 is often a little swol- 

 len or it becomes 



rhizoid-hke (Fig. 

 328 b). 



In this form the 

 polysiphonous axis 

 has always 4 peri- 

 central cells and ne- 

 ver more (Fig. 328 c). 

 While all the gather- 

 ings of the squarrose 

 form were sterile, 

 this one had stichi- 

 dia with ripe tetra- 

 spores (Fig. 327). 

 The stichidia (Fig. 

 328 a) are placed at 

 the ends of one of the ramifications of the second branch. They 

 are acute, subcylindrical of shape with broadly rounded base. In 

 the cylindrical part they are about 110 jii thick. They have a 

 longer or shorter, monosiphonous stalk composed of a variable num- 

 ber of cells up to ten. 



My description above proves that the two forms are very different, 

 and Falkenberg, too, points out that perhaps we have to do with 

 two different species. As they agree in so many respects I 

 prefer to consider them only as varieties of the same plant. The first 

 one, the squarrose form, according to Falkenberg being like the 



Fig'. 327. HeterosiphoniaWurdenianni (Bail.) Faikb. 

 var. laxa n. var. Upper part of tlie thallus witli 



young stichidia. 



'(About 35:1). 



