28 4 



DIVISION II. COURSE OF DEVELOPMENT OF FUNGT. 



without a winter's rest. The further development of the sporidia abscised from the 

 promycelium is perfectly known, at least in L. Dianthi, L. Malvacearum, and L. 

 Circaeae; the germ-tubes from the sporidia penetrate at once into the proper host, 

 either through the wall of an epidermal cell, as in L. Malvacearum, or through a 

 stoma, as in L. Dianthi, and develope a mycelium which again produces only teleuto- 

 spores. Aecidia and uredines have never been observed in these species. 



A similar relation to this between the Puccinieae which form aecidia and 

 Leptopuccinia exists between the Chrysomyxae and Leptochrysomyxa. The former 

 (Chrysomyxa Ledi and Ch. Rhododendri) form aecidia, teleutospores, and uredines 

 in the regular succession. The teleutospores (Figs. 130, 131) are cylindrical cells with 

 soft colourless membranes forming simple or branched pluricellular rows, which stand 

 densely crowded together parallel to one another and perpendicular to the surface of 

 the hymenium. They germinate as soon as they are ripe, and where they are formed. 



m 



KlG. 130. Chrysomyxa Rhododendri in a leaf of Rh. hirsutum. Vertical section 

 through a teleutospore-byer. ee epidermis of the under surface of the leaf. Adjoining 

 the spores is the tissue of the leaf traversed and distorted by mycelial filaments m of 

 Chrysomyxa ; a a row of teleutospores which have not yet germinated ; / a similar row 

 in which the uppermost teleutospore has formed a promycelium. and on this sterigmata 

 and sporidia are beginning to be formed in basipetal succession. Most of the other rows 

 show the first commencement of the formation of promycelia on the uppermost teleuto- 

 spore. Magn. 140 times. 



FIG. 131. Chrysomyxa Rhode, 

 dendri. A single isolated row of 

 teleutospores after completion of 

 germination and shedding of the 

 sporidia. 



Leptochrysomyxa (Chrysomyxa Abietis, Unger) forms exactly the same teleutospores 

 with promycelium and sporidia, which are scarcely distinguishable from those of 

 the two former species. But the germ-tubes from the sporidia produce mycelia 

 which only form teleutospores; no aecidia or uredines have ever been observed on 

 them. 



It is evident that the provisions for the life of these species are different from 

 those of the species first described. This however might be the case while the 

 morphological conditions remained the same; but here there is the important 

 difference, that the whole aecidium-generation is passed over and struck out of the 

 cycle. It may be that it does occur in some Leptopuccinieae which have not been 

 thoroughly examined as much as in Puccinia Berberidis, and that we merely have 

 not yet learnt the place and the conditions of its occurrence. We may allow the 

 possibility of this even in the four last-named species, which have been very often and 

 very thoroughly examined and in which there is no indication of any formation 



