412 



BOTANY 



white fructification occurs on Larches in South Europe ; it contains a liitti-r 

 resinous suli-tancc ami is also used in medicine. 



Many parasitic 1'olyporeae are highly injurious to the trees attacked by them ; 

 thus Jfcterobasidion annosum often cause* the death of whole forests of 1'iiies and 

 Spruce Kirs. .)/< nilins lacrymans C*) is an exceedingly dangerous saprophytio 

 s}>ecies, attacking and destroying the timber of damp houses. The niyeeliuni of 

 this fungus forms large, wliite, felted masses with firmer branched strands which 

 serve to conduct water and food substances. It gives rise to outspread, irregularly 

 shaped, pitted fructifications of an ochre or rusty-brown colour, and covered with a 



hymenial layer. Good ventilation 

 of the infected space is the best 

 remedial measure. 



6. The Agaricineae, which in- 

 clude the greatest number of species, 

 have stalked fructifications, com- 

 monly known as Mushrooms and 

 Toadstools. The under side of the 

 pileus bears a number of radially 

 disposed lamelhe or gills which are 

 covered with the basidia- producing 

 hymenium. In the early stages of 

 their formation the fructifications 

 consist of nearly spherical masses 

 of interwoven hyphre, in which the 

 stalk and pileus soon become differ- 

 entiated. The rudiments of the 

 stalk and pileus are at first enclosed 

 in a loosely woven envelope, the 

 VOLVA. In the course of the further 

 development and elongation of the 

 stalk the volva is ruptured, and its 

 torn remnants form a ring or sheath 

 at the base of the stalk, and in many 

 cases (as in the "Fly Mushroom," 

 Amanita muscaria), are still trace- 

 alile in the white scales conspicuous 



on the red surface of the pileus (Fig.361). In addition to the volva many Agaricineae 

 develop a so-called VELUM, consisting of a thin membrane of hyphal tissue which 

 extends in young fructifications from the stalk to the margin of the pileus, but is 

 afterwards ruptured, and remains as a ring of tissue encircling the stalk (Fig. 359). 

 Many of the Mushrooms found growing in the woods and fields are highly 

 esteemed as articles of food. Of edible species the following may be named: the. 

 common Field-Mushroom, now extensively cultivated, Psalliotn a, mjnxtris (Fig. 

 359), with whitish pileus and lamellae at first white, then turning flesh-colour, and 

 finally becoming chocolate-coloured ; Cantharellus cibarius, having an orange- 

 coloured pileus ; Lactarius dcliciosiis, which has a reddish-yellow pileus, and con- 

 tains a similarly coloured milky juice in special hyphal tubes ; Lcpiota procera, 

 whose white pileus is flecked with brown scales ; Amanita cacsarea with an orange 

 pileus bearing a few white scales and yellow lamellae. 



Of the poisonous Agaricineae the following are best known : Amanita nuts*' rid 

 (Fig. 361); Amanita bulbosa (Fig. 362) with whitish or yellowish pileus and the 



FIG. 361. Amanita muscaria. (Jnat. size.) I'oisoxvi's. 



