232 



MYCOLOGY 



the primary ones. The gills may be free from the stipe, adnexed, or 

 even decurrent. 



A section of a mature gill shows the following disposition of the 

 hyphal layers. The central part of the gill consists of parallel, down- 

 ward directed hyphffi, that form the trama. Running out obliquely 

 from the trama are shorter cells which constitute the subhymenium. 

 The basidia, together with their accompanying paraphyses and cysti- 

 dia, form a palisade-like layer (the hymenium) whose cells stand at 



right angles to the tramal hyphae. 

 The basidia are furnished with 

 sterigma, which bear the basidio- 

 spores (Fig. 92). In such forms 

 as the common mushroom, the 

 gill chamber is at first closed by 

 a veil known as the partial veil, 

 or velum partiale, which ruptures 

 when the pileus expands. The 

 part of this membrane attached 

 to the stipe becomes the annulus. 

 while the other part remains at- 

 tached in a shreddy condition 

 to the edge of the cap. The 

 species of A manita have a univer- 

 sal veil which covers the whole 

 fruit body, and as this enlarges 

 the velum universale is torn trans- 

 FiG. 92.-Coprinus siercorarius with versely, the lower part forming 



young and mature sporophores with gills, the death CUp, Or volva, and the 

 basidia and basidiospores and cystidia. , ,• . . 



{After Brefeid.) "PP^r P^rt sometimes remammg 



in the form of flaky pieces, which 

 are distributed irregularly over the upper surface of the cap (Fig. 93). 

 A frill-like annulus is also found at the top of the stipe in the Amani- 

 tas. It does not represent a portion of the partial veil in the Amanitas, 

 but is a membrane which is formed from a thick, loosely felted 

 layer, which separates as elongation proceeds from the surface of the 

 stipe, retaining its connection with the stipe where the stalk joins the 

 cap. It is pulled away from the stipe by retaining its connection with 

 the edges of the pendant gills as a continuous membrane, which covers 



