TUBURCINU. 321 



after the promycelium becomes divided by cross-septa in its 

 upper part, and the conidia too are frequently divided by one 

 or two septa. The two promycelial cells become detached, 

 while the conidia begin to fuse together by means of out- 

 growths near their base ; thereafter each conidium gives 

 out a secondary conidium, into which the plasma-contents 

 pass over. A similar formation of secondary conidia may take 

 place without previous fusion of the primary conidia. The 

 conidia fall apart, and they, as well as the upper promycelial 

 cells thereby left isolated, grow out as hyphae. It must be 

 these hyphae which infect the rudimentary shoots of Trientalis 

 when they are already partially formed for next year. The 

 resulting mycelium permeates the shoots in the following spring, 

 and branches of it emerge through the stomata, or pass between 

 the epidermal cells and break the cuticle, to grow up either at 

 once as conidiophores, or to form on the surface of the leaf a 

 web from which conidiophores arise. The pear-shaped conidia 

 are attached by their broader side, and easily fall off, leaving 

 the conidiophores free to produce new conidia. The conidia 

 are capable of immediate germination, and may produce a 

 lateral germ-tube, which grows directly upwards, and gives off 

 secondary conidia ; or the conidia themselves grow out into 

 hyphae, capable, as Woronin proved experimentally, of carrying 

 out infection. Such hyphae penetrate between the walls of 

 adjacent epidermal cells, and give rise to a mycelium which 

 spreads in a centrifugal direction and forms the spore- 

 masses. 



This same fungus has also been found on Miphrasia lutea 

 and Paris quadrifolia. On Euphrasia, according to Winter, 

 it causes formation of large swellings, accompanied by consider- 

 able deformation of leaf and stem. 



T. primulicola (Magn.) Kiihn.^ (Britain). This smut attacks 

 flowers of Primula acaulis, P. officinalis, P. elatior, P. farinosa. 

 In cases described in Germany, the blooms were generally 

 attacked in the filaments or connective of the stamens, but also 

 in the anthers, the ovaries, pistil, stigma, and sometimes in the 

 calyx-tube ; while the whole flower-head was more or less 

 discoloured by the black spore-dust. The mycelium permeates 



1 Magnus, Botan. Verein Brandenburg, 1878. Kiihn, "die Entwickehmgs- 

 gesch. d. Primelbrandes," Natur/orsch. GeseU. zu Halle, 1892. 



X 



