CHA PTER V. — COMPA RA TI VE REV IE W. — HYMENOMYCE TES, 



*93 



covered by the volva and borne on the broad and stoutly conical stipe-primordium 

 (Fig. 135 a). 



At first only the upper surface of the pileus appears distinct and separate from 

 the volva ; then the commencement of the hymenial layer or the lamellae is seen in 

 the general shape of a narrow ring beneath the upper surface of the pileus and 

 separated from the volva by a layer of tissue, the future body of the pileus (b, c). All the 

 principal parts of the structure are now commenced ; the whole tuber has reached 

 a size of 10-20 mm., being irregularly ellipsoid in shape and having towards the apex 

 a deep depression with thickened and rounded edges, in the middle of which the 

 young pileus with the volva 



forms a regularly shaped J o 



cushion-like prominence. All 

 these parts are shown succes- 

 sively and sharply defined in 

 section, most sharply in a me- 

 dian longitudinal section, but 

 none of them with distinct 

 edges bounded by ever so 

 small a gap. The definition 

 is entirely due to the fact that 

 the structure is different in the 

 different parts ; the young hy- 

 menium, the outer surface of 

 the pileus, and a strip which 

 runs vertically from this into 

 the middle of the stipe are 

 formed of slender hyphae and 

 have little air or none in the 

 interstices of the weft; they 

 thus have an aqueous trans- 

 parence and are contrasted 

 with the tissue round them, 

 which is white in colour from 

 the presence of broader inter- 

 stices filled with air and has 

 inflated hyphal cells among its 

 narrowly cylindrical elements. 

 If the air is removed the sharp- 

 ness of the definition at once disappears. It should be particularly observed 

 that the hymenial layer, which received a passing notice above, is seen to be 

 separated into the future lamellae from the moment that it first becomes visible ; 

 these appear as plates of tissue stretching from the inner surface of the pileus to the 

 outer surface of the stipe. Brefeld observed in Amanita muscaria that there was 

 never anything more than a narrow space containing air between each pair of plates; 

 according to Woronin's and my own previous investigations, especially into A. 

 albescens, it is shown by tangential longitudinal sections that a narrow plate of air- 



FlG. 135. Amanita riibcsceu?, l : r. a — d radial longitudinal section through com- 

 pound sporophores of different ages. Successive stages of development according to 

 the letters, d a small and nearly mature specimen, f transverse section through d 

 in the direction of the dotted line, g thin tangential longitudinal section through the 

 young pileus and lamellae of*, slightly magnified. The inner portion only of the volva 

 is shown. In all the figures v is the volva, r the annulus (armilla), h the substance 

 of the pileus, /lamellae, a — d very slightly magnified, a o mm. long and the rest 

 in proportion, £" slightly magnified. 



