

356 BOTANICAL GAZETTE [November 



At the constricted points one finds pseudo-septa in various 

 stages of development. These peculiar structures are unlike any- 

 thing in the way of septa that I have seen described. In the older 

 parts of the plant they reach their most perfect development, and 

 then only incompletely separate the protoplasm of the adjacent 

 segments. In a single well developed plant of some age, one may 

 find the pseudo-septa in all stages of formation. They are first 

 seen as separate processes or thickenings protruding inwardly from 

 the wall at the constrictions. These processes increase in length, 



m 



fusion takes place and a definite central plate results. 



Fig. 1 8, a-d, represents different stages of development of a 

 septum, while figs. 19, 20, and 21 represent sections through such a 

 stage as that shown in fig. 18, a. In fig. 19 the section is through one 

 arm and the central plate, fig. 20 through two opposite radial arms 

 and the central plate, while fig. 21 shows a section through the 

 central plate alone. These pseudo-septa are much more highly 

 differentiated than the "cellulin" rings which are present in Gona- 

 podya and other Leptomitaceae. They permit a free interchange 

 of the protoplasm, and only under conditions of injury to the hypha 

 do they entirely close the lumen. Both the mycelial walls and the 

 pseudo-septa fail to give any definite reaction for cellulose. After 

 treatment with iodine and sulphuric acid, very rarely a slight trace 

 of blue color is seen in the mycelial walls. The pseudo-septa 

 become much swollen and take on a deep orange color, resembling 

 in this respect the reaction secured by Pringsheim (5) f° r the 

 "cellulin granules." 



In young actively growing plants the protoplasm is much 

 vacuolated, granular, and contains, distributed throughout it, 

 prominent nuclei containing deeply staining bodies (figs. 28, 3 2 )- 

 Aside from the nuclei, there occur other deeply staining bodies 

 which are more or less regular in form and of various sizes. They 

 are very probably similar to those described by Reinsch (6) as 

 independent, endogenously produced cells, which he was inclined 

 to believe were the origin of the reproductive organs (see figs. i 2 > 

 28, 32). Thaxter (9) observed these same bodies in B. Prmgs- 

 heimii, and saw no reason for assuming that they were other than 



