l(i Veit I'ükchek Wittrock. 



are far IVoin rare, oypecially in tlm principal filament. Here it, does 

 not suUloni happen, especially in specimens that are l)nt hall-fertile, that 

 the formation of spores takes place even quite acropetall}- (pi. 2, fig'. 7). 

 Rules as to the order of the formation of spores which have, as it has 

 seemed to me, no exception, arc l:o That the top spore has, at least 

 in shorter branches, been developed before all the inclosed spores of 

 the branch, and 2:o That the spore which is developed by the support- 

 ing cell of the branch (if such a spore be developed, which is not al- 

 Avays the case), is formed hvtcr than all the spores in tlie supported 

 branch. — Although the material of the other species of Pit /io/>}iora which. 

 I have had to examine has not in general given me opportunities to 

 make observations on the order of the spore formation, still I have 

 now and then succeeded in making aii observation on this head. Thus, 

 it is distinctly seen in the specimen of P. rrqunU.inoh. which I have 

 represented pi. 1, fig. 5, that here the formation of spores takes place, 

 upon the whole, in a basipetal direction, even if the second spore from 

 above be developed somewhat later than the third. 



As has been mentioned above, the formation of spores belongs, 

 as a rule, to the cauloïd part of the thallus. As exception spores may, 

 however, be formed also in the rhizoïd part at least of F. kcwensis nob. 

 (pi. 4, fig. 9 — 11), F. Cleveana nob. (pi. 4, fig. 14, 18) and F. polymorplin 

 nob. (pi. 4, fig. 19). In P. kewensis nob. I have even found rhizo'ids 

 Avith as much as three spores (pi. 4, iig. 11). The formation of spores 

 in the rhizoïd takes place in exactly the same manner as in the cauloïd, 

 only with the difference necessitated by the different direction of the 

 increase, so that the spore is here formed not in the upper, but in the 

 lower part of the mother cell. 



As to the time of the spore formation it is, judging from the 

 observations on this head that I have had access to, very different in 

 different species. In F. keicenm nob. I have seen the formation of 

 spores take place in the months of July and August. Of F. œqualis 

 nob. I have fertile specimens, also collected in July. P. Cleveana nob. 

 and F. Zelleri (v. Mart.) nob. are found with spores in October, F. 

 Roettleri (Roth) nob. in January and F. sumatrana (v. Mart.) nob. in 

 March. (At what time the formation of spores takes place in F. j)oly- 

 morpha nob. is cjuite unknown to me). However, it may be probable 

 that the formation of spores takes place during longer periods of the 

 year than those which have been indicated above for the different 

 species. 



