298 DIVISION II. COURSE OF DEVELOPMENT OF FUNGI. 



details will be found in special descriptive treatises and in Hoffmann's, R. Hartig's 

 and Brefeld's anatomical works. Most Tremellineae are distinguished by the 

 circumstance that their whole body, except a thin cortical layer at most, consists 

 of gelatinous tissue capable of the utmost degree of swelling. See above, pages 

 9 and 12. 



The structure of some fleshy species is partly pseudo-parenchymatous, and this 

 is associated with other and peculiar appearances. The characteristic composition 

 of almost all parts of the Amaniteae out of slender confusedly woven hyphae 

 and inflated bladdery cells, which are segments of the hyphae, has been already 

 mentioned. The volva also has the same structure, and is thus distinguished from the 

 surface of the pileus, which continues to be formed of slender closely compacted 

 hyphae, and in A. muscaria assumes the character of a gelatinous felt. Further 

 instances of a structure which departs from that of simple hyphal filaments are seen in 

 the Russula, Fr. and Lactarius, Fr. groups of the Agaricineae, and a description of 

 them may be reproduced in this place. 



The compound sporophores in these Fungi are round umbrella-shaped pilei with a 

 thick central stipe, and they are of a firm fleshy consistence. 



Sections in different directions through the pileus and stipe of Russulae, which were 

 examined in the case of R. integra and R. olivacea by Bonorden, and in R. integra, 

 Fr., pileo rubro and R. adusta, P. by myself, show two different kinds of tissue in 

 all parts, except in the outermost surface, which is formed of a close weft of slender 

 hyphal filaments sometimes and in some parts of a gelatinous consistence, as, for 

 example, in the pileus of R. integra. There are large groups of broad, pellucid, 

 roundish cells, and riband-like strands composed, of slender branched hyphae which 

 contain an abundance of protoplasm. The pellucid groups of roundish cells have an 

 irregularly elongated shape in the stipe with rounded or pointed extremities, the longer 

 diameter being parallel to the stipe. In the fleshy substance of the pileus they are 

 roundish and irregularly disposed. The slender filaments of the plates and strands 

 grow round them in every direction and in such a manner that the former appear on a 

 cross section as an irregular network, the meshes of which are filled by the round- 

 celled tissue. The arrangement of the cells in the latter shows no fixed order in the 

 middle of the stipe and in the pileus ; towards the surface of the stipe they are placed 

 in irregular horizontal rows or layers. The size of the groups and that of the individual 

 cells gradually diminishes from the middle to the surface of the sporophore, while the 

 thickness of the bands of slender filaments increases. The fibrillation in the stipe is 

 chiefly longitudinal, but follows no rule in the pileus. Branches separated from their 

 hyphae may be seen to enter the round-celled tissue from all parts, and branch 

 irregularly and spread in it. Closer observation of sections in which the filaments 

 have been unravelled makes it quite plain that the round cells are connected in such 

 a manner with the hyphae that are woven round them and spread among them, that 

 they must be members of greatly enlarged branches of these hyphae with the form of a 

 rosary; transition-forms also may be seen between the truly round cells and the narrow 

 cylindrical members of the hyphae which have grown between them and around them. 

 Bonorden was the first who called attention to this point ; in others the connection and 

 development of the two kinds of tissue still require more careful examination. 



The structure of Lactarius has been investigated by Bonorden principally in 

 Lactarius pallidus, by Hoffmann in L. mitissimus, and by myself in L. subdulcis, L. 

 chrysorrhoeus, and L.deliciosus. Here, as in Russula, there are groups of broad roundish 

 cells which appear to be set in a weft of slender cylindrical hyphae (Fig. 136). The 

 superficial or cortical layer is formed of the latter only. The large-celled groups have 

 much the same shape as in Russula, but they are usually narrower and more sharply 



