﻿60 Arthur and Fromme: A new Endophyllum 



about 90 M, before the septa appear. The promycelium Is divided, 

 as a rule, into four uninucleate basidiospore initial cells and a 

 basal stalk (Figs. 6-12). Each basidiospore initial cell gives rise 

 to an ellipsoid basidiospore on a sterigma (FiGS. 7-9). Under 

 suitable conditions the basidiospore germinates at maturity with 

 a slender germ tube that may issue from the apex (Figs. 6, 8) 

 or from the base near the attachment of the sterigma (Fig. 9). 



The common practice of germinating rust spores in the in- 

 verted drop of the Van Tieghem cell is undoubtedly the reason 

 why the true character of the very common and much studied 

 Gym. interstitialis remained obscure for so many years and Kunkel's 

 discovery is attributable to the important departure in method 

 of germination that he employed. 



The production of basidiospores is dependent to a considerable 

 degree on the exposure of the promycelium to a free air surface. 

 If the teliospores are floated on an upright drop of tap water on a 

 slide placed in a damp chamber basidiospores are freely formed, 

 but if sown in an inverted drop of water in a Van Tieghem cell no 

 basidiospores are produced and spore germination may be totally 

 inhibited. A drop of a five percent non-nutrient gelatin may 

 be substituted for the upright drop of water to secure greater 

 stability. If spores are available in large quantities they may be 

 dusted on the surface of water or non-nutrient gelatin or agar in 

 a petri-dish. On a moderately hard agar the basidisopore initial 

 cells produce germ tubes directly without the formation of basidio- 

 spores (Figs. 10-13). 



That the moisture and air relations under which teliospores 

 are germinated have a marked effect on the character of their 

 germination has also been shown by Klebahn,* who worked with 

 teliospores of Puccinia malvacearum. He found that normal 

 promycelia and basidiospores were produced if the spores were 

 in contact with air and not surrounded by a film of water, but if 

 surrounded by water with the air shut out only long thin tubes 

 were formed. 



There is perhaps no basis on which species with aecidioid telia 

 can be distinguished from the aecia of long-cycle forms except 

 in the behavior of their spores on germination. A perennial 



* Klebahn, H. Zeitsch.f. Pfl.kr. 24: 1-32. 1914- 



