240 HYDNEI. 



Hydnum. ** Simple, tuberculiform, immarginate. 



18. H. erinaceum Bull. Pileus 20 cent. (8 in.) and more 

 broad, often much less, white, becoming yelloiu, fleshy, elastic- 

 tough, pendulous, tubercular, immarginate, torn into fibrils 

 above. Spines very long, 4-6 cent. (1)^-2% in.), straight, equal, 

 pendulous. 



Striking, changeable in form, in the form of a heart when most perfect, 

 often with the rudiment of a lateral stem. Internally as if latticed in a 

 branched manner. 



On trunks of oak, beech, &c. Rare. 



Spores white, plain, 5x6 mk. W. G.S. Name erinaceus, a hedgehog. 

 From its appearance. Bull. I. 34. Fr. Hym. Eur. p. 608. Berk. Out. p. 

 259. C. Hbk. n. 852. Vittad. t. 26. Kro'mbh. t. ST./. 1-3. 



19. H. caput-Medusae Bull. White, then fuliginous-cinereous, 

 fleshy, tuberculiform, somewhat stipitate. Spines on upper 

 surface distorted, the lower ones long, straight. 



Large. The trunk is dilated into a pileus, which is covered over with 

 slender spines on all sides. 



On trunks. Rare. 



Name Medusa's head. Bull. t. 412. Fr. Hym. Eur. p. 608. Berk. 

 Out. p. 259. C. Hbk. n. 853. 



IV. APUS. Pileus sessile, dimidiate, &c. 

 * Pileus fleshy, soft. 



20. H. cirrhatum Pers. Pileus pallid, fleshy, expanded, 

 fibrilloso-curled above with scattered decumbent abortive spines, 

 thefimbriate margin incurved. Spines very long, 10-16 mm. 

 (5-8 lin.), slightly tough, equal. 



Simple or imbricated. Varying white, light yellowish, rufescent. 

 On a beech-tree. Epping Forest. 



Name cirrus, a curl, lock of hair. Pileus curled. Pers. Syn. p. 558. Fr. 

 Hym. Eur. p. 609. Sv. dtl. Sv. t. 71. /. i. B. 6* Br. n. 1370. Fl. Dan. t. 

 1789.7. 2. 



21. H. diversidens Fr. Pileus 5 cent. (2 in.) broad, white 

 fleshy, thick, substipitate, very irregularly shaped, densely beset 

 above "with erect, variously shaped, incised teeth, clothed at the 

 entire margin with club-shaped spines, and beneath with entire 

 awl- shaped regular spines. 



Colour almost that of repandum. Singular from having spines of three 

 kinds. Allied to H. cirrhatum, but not caespitose, more irregularly shaped, 

 here and there lobed. 



