PANAEOLUS CAMPANULATUS 



315 



in all species occasional variations from the normal number of 

 sterigmata occur, and in this respect basidia may be likened to 

 certain compound leaves and flowers of the Phanerogamia, where 

 analogous variations in the number of the elements are not infre- 

 quent. We will now discuss the arrangement of the sterigmata 

 in the different types of basidia, beginning with the simplest. 



Monosterigmatic basidia, 

 according to Patouillard, occur 

 normally in Pistillaria macu- 

 laecola Fckl. and also in the 

 Gastromycete Hydnangium 

 monosporum Boud. et Pat., 

 whilst in Pistillaria fulgida 

 Fr., although the basidia are 

 usually monosterigmatic, 

 occasionally they are disterig- 

 matic. 1 I myself so far have 

 not examined these species. 

 However, I have observed 

 monosterigmatic basidia in 

 the cultivated Mushroom, 

 Psalliota campestris 2 (Fig. 105), 

 and in Coprinus bisporus 

 Lange (Figs. 106 and 107). 

 In both these species the 

 basidia are normally disterig- 

 matic, but monosterigmatic 

 basidia occur as by no means 

 infrequent exceptions. Where a basidium is monosterigmatic, the 

 sterigma always occupies a central position at the top of the 

 basidium (Fig. 105, b and c). The spore, however, is not sym- 

 metrically set on the end of the sterigma, but is attached 

 unilaterally in the manner which is characteristic of the spores 



1 N. Patouillard, Tabulae analyticae fungorum, eer. 1, 1883-1886, nos. 47, 

 50, 692. 



2 Vide infra. Monosterigmatic basidia are shown for the Mushroom in 

 Figs. 146 and 147, Chap. XIII. 



FIG. 106. Coprinus bisporus. Two fruit- 

 bodies growing on a stick sent from 

 Kew. The disc remains prominent 

 until exhaustion of the pileus. Photo- 

 graphed at 10 A.M. at Winnipeg. 

 Natural size. 



