1889.] MICROSCOPICAL JOURNAL. 175 



the characteristic situation of these bodies, but in some species, as 

 yEcidium hepaticarum, they are only sub-cuticular. The outer portions 

 or periphery of the bodies are composed of many erect, closely-pressed, 

 bristle-like filaments, paraphyses, which arise from the stroma or mass 

 of miscellaneously tangled hyphae below. Inside this wall of para- 

 physes and lining the cavity is what may be fitly termed a hymenial 

 layer, from which arise filaments, short, thick sterigmata, which bear 

 the spermatia. 



The most noticeable feature connected with the composition of these 

 bodies is the variation in the hyphae as compared to the other spore- 

 forms. While the ordinary hyphae from which the branches arise to 

 form the body range from 3 to 6 p. in diameter, the paraphyses seldom 

 exceed 3 >j., and the sterigmata and the filaments which form the stroma 

 are even smaller. The spermatia are abstricted in conidia, form series 

 from the apices of the sterigmata, which stand at right angles to the 

 hymenial layer, so that the centre or cavity of the flask-like spermogone 

 is early filled with the small round or oval bodies, which finally ooze 

 out at the apex in a mucilaginous conglomerate. These bodies when 

 placed in a weak solution of honey or sugar pass through a budding 

 germination not unlike the multiplicative process to be seen in the yeast 

 plant, Saccharomyces cereviseae (fig. 5). As to the true nature and 

 purpose of these bodies in the economy of the fungus nothing is known. 

 Some, reasoning by analogy, hold that they represent the male element 

 in reproduction, while some are inclined to consider them as a simple 

 conidial spore form, the complete life of which is not as yet known. 



Soon after the formation of the spermogones the neighboring hyphae 

 begin to form interlacing masses deeper down in the plant tissues, which 

 are the beginnings of new fruit, the aecidia. By this time the diseased 

 portion of the lamina of the leaf has become much thickened, cushioned 

 under the spermogones, due to some stimulating effect of the parasite 

 causing an abnormal development of the mesophyll tissues. The hyphae 

 have also become much closer branched, more septate, and a yellow 

 oleaginous granular matter appears in considerable quantities in the 

 protoplasm . This may also be seen in large quantities in the paraphyses 

 of the spermogones, and seems finally to constitute a principal element 

 in the contents of the aecidiospores. 



In yEcidium hepaticarum on Hepatica triloba, just previous to the 

 appearance of the basidia from which the spores are abstricted, the 

 aecidium, by sectioning, is found to be a solid ball of clearly interwoven 

 and united filaments (fig. 7). When the sphere has enlarged until its 

 most exterior surface is about in contact with the epidermis, the young 

 basidia appear as small thick branches arising from a point in the ball 

 slightly below the median line (fig. 7, d) . The outermost ones cor- 

 respond in position to a row of paraphyses, and, uniting, form the en- 

 closing wall of the fruit, the peridium, which upon the rupture of the 

 epidermis turns back, forming a cup-like opening from which the spores, 

 which have already been abstricted from the internally situated basidia, 

 may escape. This course of development is essentially true for the 

 aecidium of Puccinia graminis, excepting only that portion of the de- 

 scription which applies to the formation of the aecidium just pi - evious 

 to the appearance of the basidia. In this case there is at first formed 

 an aggregation of mycelia, which constitutes the stroma or spore-bed 

 from which the basidia arise. On the sides this mass of filaments ex- 



