30 GUIDE TO THE MODELS OF FUNGI. 



are a hundred British species of Pratcllce, eight of which are repre- 

 sented by models. The species with brownish-purple and brownish 

 spores are often confused with the Dcnuini. Some PraMlce produce 

 few spores, and the gills remain white. 



Sub-genus 21. Psalliota. — There are eleven British species 

 of Psalliota (with many varieties) ; two species are represented by 



models. Psalliota agrees in structure and 

 habit with Lcpiota ; but the spores are dark 

 purple shaded with brown, not w^hite ; the 

 gills are free, and the stem is furnished 

 with a ring. They begin to appear at the 

 end of summer, and several of the larger 

 species are well-known esculents. 



58. Agaricus arvensis Scha^ff. Horse- 

 Mushroom. — Pileus from three to twelve 

 or more inches across, whitish or whitish- 

 buff in colour, very fleshy, globoso-cam- 

 panulate, then flattened, flocculoso-mealy 

 Fig. 2s.-Typefbi^m of Psalliota. ^heu young, then slightly silky or squamu- 

 AgaricuscampestrisL. (One- lose, dry; flesh thick, Compact, white, 



third natural size.) ,11 ■ ^ ,1 • , , 



generally changmg to yellowish, when cut 

 or broken dull brownish-yellow or brownish-buff; gills free, ventri- 

 cose, broader in front, white, clay-coloured, then reddish-fuscous, at 

 length purple-black, often moist but never deliquescent ; stalk three 

 or four inches long and an inch or more thick, smooth, white, often 

 swollen, hollow, with a lax floccose pith, obsoletely marginato- 

 bulbous when young ; ring large, spreading, or pendulous, appears 

 double with the upper portion membranaceous, the lower thicker 

 more or less free at the circumference, and radiatcly split. 



A. arvensis may be only a coarse variety of the true mush- 

 room, A. cawpestris. A. arvensis grows in manured places, often 

 among rank grass, by grassy roadsides, and in orchards, pastures, 

 and on downs ; it especially affects the neighbourhood of trees, 

 hedges, bushes, and bracken. It often grows in rings of enormous 

 size. 



There arc two well-marked varieties of the horse-mushroom: 

 one, named A. villalicus Brond., is large and very scaly ; another, 

 var. purpurascens Cooke, growing in woods, has the pileus at length 

 tinged with purple. 



Esculent ; when fresh and young this species is juicy and 

 delici()us, but it becomes tough and dry with age. It makes a good 

 ketchup. Most of the market mushrooms from fields belong to this 

 species. 



A. arvensis requires to be carefully distinguished from the 

 poisonous A. faslibilis and A. crusliilinifonnis, already described. 

 Sometimes A. radicosus, notwithstanding its odour of prussic acid, 

 is mistaken for this mushroom. 



