HOTSON. — cri.TUKK STTDIKS OK FrNHJI. 27.'^ 



Papulospora. 



Mycelium extensive or scanty, flocculent or procumbent, usually 

 white but sometimes dark colored. Reproduction by means of 

 bulbils, i. e., reproductive bodies of more or less definite form, com- 

 posed of a compact mass of homogeneous or heterogeneous cells 

 which may be few or many, but are always developed from primordia 

 of more than one cell. Other modes of reproduction may be present. 



For convenience bulbils may be grouped under three heads: those 

 which form an intercalary primordium of several cells; those which 

 typically originate from a primary spiral; and those that are pro- 

 duced by a perpendicular branch or branches which do not form a 

 spiral. 



As has already been pointed out the distinction between simple bul- 

 bils and compound spores on the one hand, and the more complex bul- 

 bils and sclerotia on the other, is not always definite, and in certain 

 instances it is difficult to determine to which category a given struc- 

 ture belongs. Compound spores are reproductive bodies of more than 

 one cell, having a more or less definite form, and are usually the result 

 of a successive or simultaneous division of a single cell. On the other 

 hand, sclerotia are compact bodies capable of reproducing the plant 

 and formed rather by the massing together of vegetative filaments, 

 forming a pseudoparenchymatous tissue, but not developed from a 

 group of more or less definitely related cells. Moreover, the individual 

 cells of a sclerotium are not at all spore-like or independent of each 

 other. Bulbils, are reproductive bodies, more or less definite in form 

 and mode of development, and normally derived from primordia of 

 more than one cell, rather than the result of successive or simultaneous 

 divisions of a single cell, and their individual cells are more or less 

 independent and spore-like. 



Papulospora immersa n. sp. 



Plate 10, Figures 17-25. 



Mycelium white, septate, scanty, procumbent, growing in or on 

 the substratum; bulbils, light brownish-yellow, irregular, 88-150/1 

 in diameter, but very variable, sometimes the long axis exceeding 

 260 n, often immersed; central cells large 28-55 m in diameter, 

 angular, with conspicuous oil globules; 50-70 cells in surface view, 

 but in irregular forms 100 cells, no differentiation of internal and 

 external cells. No other mode of reproduction at present known. 



