236 



MONOGRAPH OF THE LABOULBENIACEiE. 



is suffused, and give to the latter the punctate appearance peculiar to many species. 

 The presence of these fibrillaa has not been definitely determined in genera other 

 than Laboulbenia, and even in this case, although so conspicuous in many species, 

 they no not seem to be of invariable occurrence. 



The substance of the cell walls as well as of the general envelope give, when 

 treated with iodine and sulphuric acid, or with Schultze's chloroiodide of zinc solution, 

 no blue color. 



The contents of the cells, especially those of the receptacle, are usually more or less 

 characteristic while the plant is alive, and consist of rather dense granular proto- 

 plasm, in which, as a rule, certain highly refractive spherical oily masses are conspicu- 

 ous. In some instances these masses are few in number, one or more of them being 

 often very large (Plate V, figs. 4 and 5), while again they may be more numerous and 

 uniform in size, completely filling the cells, as in the case of Laboulbenia Harpali, L. 

 Philonthi, and many others. In general, however, they are more or less variable in 

 size, and present the appearance indicated in fig. 15, Plate II. In glycerine they soon 

 become indistinguishable, and are thus not represented in the accompanying figures, 

 which were drawn, with few exceptions, from glycerine preparations. 



The protoplasm of adjacent cells, the origin of which is the same,, is connected by 

 a conspicuous strand of the same substance, which passes from one cell to the other 

 through a well marked perforation of the cell wall, the connectionlbeing demonstrated 

 with great ease by treatment with potash and subsequent staining (Plate III, figs. 11- 

 12 ; Plate II, figs. 16-18). In many instances, also, it may be seen in the living plant 

 without the use of reagents. This protoplasmic connection is found in all the cells, in- 

 cluding those of the trichogyne, when this organ is multicellular. In many cases in 

 which the cells had been separated by potash, and the connecting protoplasmic strand 

 stretched between them, I have seen a slight enlargement like that indicated in fig. 

 12, Plate III, recalling the similar structure through which the strands of pro- 

 toplasm pass in the Florideae. I have, however, been as yet unable to determine its 

 exact nature. 



A single, usually large, nucleus is found in the contents of every cell, and is 

 often readily seen without the use of reagents ; while in other cases it is by no means 

 easy to demonstrate, owing to the difficulty which is usually experienced in staining 

 the cell contents. The nuclei are spherical or nearly so, and usually contain a large 

 nucleolus (Plate V, figs. 20 and 24; Plate I, figs. 7, 15, 16; Plate II, figs. 3 and 13). 

 The nuclear changes accompanying cell division have not been determined; but from 

 the occurrence of conditions like that represented in fig. 7, Plate I, it would appear 



