t;UIDE TO THE MODELS OF FUNGI. 



79 



The British Truffle. — Hard and black 





207. Tuber aastivum Vitt, 

 at maturity, polygonally 

 warted outside and mottled 

 with white and yellowish- 

 brown inside. 



It is usually subterra- 

 nean, but is seldom found 

 more than threeor four inches 

 beneath the surface ; it is 



sometimes half exposed. It Fig. go.-TuberaestivumVitt. and section. (Natural 



*■ SlZd^ x\SCUS X lOO* 



is generally about the size of 



a walnut, but may attain a diameter of three or more inches. In 

 rare cases single specimens weigh two, three, or four pounds. It is 

 found in perfection from July to late autumn. It grows in copses, 

 hedgerows, and open places in plantations gregariously with other 

 species of Tuber, generally in plantations of beech, oak, or birch — 

 rarely pine — on argillaceous or calcareous soil. 



The odour of T. cestivum is potent and to some persons agree- 

 able, and can sometimes be detected where truffles grow. Squirrels 

 and pigs are fond of truffles, and scratch them up. 



Edible, but hard and indigestible. 



The truffle of France, used \npdte de foie gras and poulard truffe, 

 is Tuber melauosporum Vitt. The truffle used in Italy is T. magnatmn, 

 which is garlic-scented. These species have not been recorded as 

 British. 



GENUS LV.~CHOIROMYCES Vitt. 

 Integument even ; base definite ; sporidia spherical. 



\ 



208. Choiromyces meandriformis Vitt. White Truffle. — Ex- 

 terior is marked with depressions, somewhat like the eyes of a 



potato. The whole plant 

 , >. indeed resembles ex- 

 ^|j\ ternally an ordinary pale- 

 skinned potato, both in 

 general colour and size. 

 The interior is marbled 

 with brown and white 

 veins ; it becomes yellow 

 in drying. When young 



Choiromyces meandriformis Vitt. and section. sCCntleSS but when 



(One-half natural size.) Ascus x 100. ' , , 



mature the odour is 

 very strong, like decaying cheese. 



This is a large species, and generally grows in open, hilly places, 

 half buried in stiff soil ; it prefers oak plantations, and may be found 

 in summer and autumn. When young this trufQe is white ; at 

 length it becomes pale buff or brownish. 



Esteemed, but has been known to produce unpleasant effects 

 when eaten in a raw state. 





;...y^ 





T\%. 91.— 



