138 FUNGI. 



in Ag. rutilans, Sch. In Uygroplwrus they are ratlier irregular, 

 reniform, or compressed in the centre all round. Hoffmann* has 

 given a figure taken from Ag. chloroplianus, and Seynes verified 

 it upon Ag. ceraceus, Sow. (See figures on page 121.) 



The exospore is sometimes roughened, with more or less pro- 

 jecting warts, as may be seen in Russula, which much resembles 

 Laclarius in this as in some other particulars. The spores of 

 the Dermini and the Hyporhodii often differ much from the 

 spheerical form. In Ag.pluteus, Fr.. and Ag. p7iaiocepl>alus, Bull, 

 there is already a commencement of the polygonal form, but the 

 angles are much rounded. It is in Ag. sericeus, Ag. rubellus, 

 &c., that the polygonal form becomes most distinct. In Dermini 

 the angles are more or less pronounced, and become rather acute 

 in Ag. murinus, Sow., and Ag. ramosus, Bull. The passage from 

 one to the other may be seen in the stellate form of the conidia 

 of Nyctalis. 



It is almost always the external membrane that is coloured, 

 which is subject to as much variation as the form. The more 

 fine and more delicate shades are of rose, yellow-dun or yel- 

 low, violet, ashy-grey, clear fawn colour, yellow- orange, olive- 

 green, brick-red, cinnamon-brown, reddish-brown, up to sepia- 

 black and other combinations. It is only by the microscope 

 and transparency that one can make sure of these tints ; upon 

 a sufficient quantity of agglomerated spores the colour may be 

 distinguished by the naked eye. Colour, which has only a slight 

 importance when considered in connection with other organs, 

 acquires much in the spores, as a basis of classification. 



With the growth of Agarics from the mycelium, or spawn, we 

 are not deficient in information, but what are the conditions 

 necessary to cause the spores themselves to germinate before our 

 eyes and produce this mycelium is but too obscure. In the culti- 

 vated species ,we proceed on the assumption that the spores have 

 passed a period of probation in the intestines of the horse, and 

 by this process have acquired a germinating power, so that when 

 expelled we have only to collect them, and the excrement in which 



* Hoffman, " Icones Analytics Fungorum." 



