On the Pithoph-oeace^e. 



61 



or even four, if the wall marked w, and not that marked tr", was the one first 

 formed in the germination. (Regarding this, see the paragraph on the germination). 

 As to the specimens that are represented pi. 5, figs. 1 and 2, it is impossible to 

 decide how much belongs to the rhizoid part, 'when it is not known with certainty 

 which part of the specimens has belonged to the original, germinated spore. If 

 the supposition were true, that the irregularly shaped organs marked sg are trans- 

 formations of this spore, only the processes rh, pointing downwards, would belong- 

 to the rhizo'id part. Sometimes no transversal wall is formed in the spore at the 

 germination, and then the rhizoid either does not exist, or is only rudimentary. 

 The former is the case if the germinating spore has not at all been elongated 

 downwards (pi. 2, fig. 13 sgb; pi. 4, fig. 12 sgb; pi. 5, iig. 3 sg) ; the latter if it has 

 been somewhat elongated, but without a parting wall between the cauloid and the 

 rhizoid having been formed (pi. 4, figs. 13 and 14 rh; pi. 5, fig. 6 rh). PI. 4, tig. 

 14 shows a case, when the forming of a parting wall was commenced, but without 

 being completed. 



Sterile specimens differ from the fertile by stronger ramification — 

 branches of the 2:d degree regularly existing * — and by the branches being 

 placed two and two opposite to each other as often as singly. 



'Measurements. This species is the smallest one in the whole genus. Its ve- 

 getative cells have, it is true, a greater diameter than those of P. kcivensis nob., 

 but the length of the individual cells as well as more especially of the whole plant 

 is considerably less. The greatest specimens that I have seen have been only 25 

 millimeter long, and specimens of a length of only 4 - 5 millimeter are not rare. 



Fertile specimens. Cauloid part of the t hall us. The cells of the 

 principal filament are on an average 70 ft thick; the smallest observed thickness 

 is 60 |« and the greatest 90 /.i. The cells in the brandies of the l:st degree arc 

 on an av: 55 ft thick. The limits of variation are 50 /.i a '.id (JO /<. The branches 

 of the 2:d and 3:rd degree are not much less thick than those of the l:st; the 

 diameter of the cells is on an av. 50 ft; the smallest diameter 45 fi and the greatest 

 55 ft. The length of the vegetative cells is less in this species than in other 

 species. Very short cells (1 '/ 4 — 2 times as long as thick) occur not seldom in the 

 principal filament (pi. 4, fig. 13) as well as in the branches. Especially the cell 

 just beneath a terminal spore has this form (pi. 5, fig. 4). Very long cells (such 

 as in P. kcwensis nob.) do not exist. Only very seldom the cells are 20 times, 

 generally only 4 — 9 times as long as thick. The thickness of the terminal spores 

 is on an av. 1)3 /i and their length, on an av. 232 fi The limits of variation arc 

 indicated by ^'-J* I™ ™ ft. The cask-shaped spores arc on an av. 102 ,u thick, 

 and 210 p long. ' The limits of variation are indicated by «'- 2 ™ ^ im iso /(> The 

 cylindric spores are on an av. 70 fi thick and 104 ft long. Their limits of variation 



ova th. 50 68 70 90 ii 

 tUL/ 1. 120, 220, !14, 210 l"' 



The cell of the rhizoid has a rather variable length. Most frequently it is 

 very short, l'/ 4 -4 times as long as thick (pi. 4, tigs. 15 and 16), but sometimes it 

 is more developed as to length, as much as 10 times as long as thick (pi. 4, 

 fig. 17). 



