300 AGARICUS. 



the ends, or have much-branched ends, or have a large 

 swelling at the base. 



The ascocarps are just visible to the naked eye as black 

 dots on the diseased leaf ; they remain on the dead leaves 

 during the winter, and when germination occurs in spring 

 the ascus absorbs water, swells, bursts the sheath and its 

 own wall, and sets free the ascospores which infect the 

 young Hop shoots. In most of the Mildews each ascocarp 

 produces several asci, as in the case of Eurotium. 



MUSHROOM (AoARicus CAMPESTRIS). 



432. Mycelium, etc. The Common Mushroom 



grows in open well-manured fields usually from June to the 

 end of September; its stalk is white, short, and usually 

 quite solid ; its cap is dry and cottony above ; the radiating 

 gills on the underside of the cap are closely set, not 

 running down on to the stalk ; the gills are at first white, 

 but later turn pink, and finally brown ; the flesh of cap 

 and stalk is white, but soon turns reddish-brown on 

 exposure to the air when cut or broken. 



Gret a piece of Mushroom " spawn," which is sold in 

 pressed blocks by seedsmen, and note its fibrous peat-like 

 texture. Put a small piece on a slide in water, tease it 

 out with needles, and note (1) the hyphae are largely 

 bound together into bands or bundles, from which single 

 hyphae are here and there given off ; (2) many of the 

 hyphae are encrusted with rod-like crystals, consisting 

 of calcium oxalate test with acids. The " spawn " con- 

 sists of a mixture of dung and loamy soil, permeated by 

 the resting mycelium, the bands of hyphae being visible 

 to the naked eye their whiteness is largely due to the 

 encrustation of crystals. 



Get a large flower-pot, or a box with holes bored in the 

 bottom for drainage, and place in it first some stones and 

 gravel, then some soil (good garden soil, mixed with cow 

 dung), then some broken-up " spawn," then a few inches 

 of soil on the top. Keep in darkness in a warm place, 

 and sprinkle with water daily. In a few weeks the growing 



