RADULUM. 



51 



Genus XXXVII.— Radulum (from the root-like appearance of Radulum. 

 the processes of the hymenium). Fr. Elench. p. 148. 



Hymenium amphigenous, tubercular. Tubercles rude, irregu- 

 larly shaped, commonly elongate, obtuse, waxy (except in R. 

 aterrimum), irregularly arranged, 

 distinct. Sporophores 4-spored, oc- 

 curring not only on the tubercles, 

 but also on the even parts of the 

 hymenium. Growing on wood, resu- 

 pinato-effused, often bursting through 

 the bark. Fr. Hym. Eur. p. 622. 



* Denuded, very variable. 

 ** Innate, removing the bark. 



* Denuded, very variable. 



1. R. orbiculare Fr. — A. First 

 season 's growth, while then yellowish, 

 orbicular, confluent, circumference 



flaxy. Tubercles elongated, some- 

 what round, scattered or fasciculate. 

 B. Second season's growth, vernal, 



flesh-colour, waxy-fleshy, smooth. Tubercles softer, shorter, as 

 if rubbed away. 



Entirely changeable in form, but very distinct. The tubercles vary 

 flexuous. 



On dead bark, birch, cherry, &c. Frequent. Oct. 



5-7.5 cent. (2-3 in. ) broad, quite membranaceous or above 4 mm. (2 lin. ) 



thick. M.J.B. Name — orbiculus, a small disc. Orbicular, round. Fr. 



Hym. Eur. p. 623. Berk. Out. p. 263. C. Hbk. 11. 874. S. Mycol. Scot. 

 n. 826. Grev. t. 278. 



2. R. quercinum Fr. — White then pallid, 5-7.5 cent. (2-3 in.), 

 somewhat round then broadly confluent, innate, crustaceous, 

 becoming smooth. Tubercles round, stout, obtuse, scattered or 

 fasciculate, irregularly shaped, floccoso-villous at the apex. 



Rude, changeable in form, often confounded with Hydnum squalinum and 

 H. variecolor. 



On dead oak. Rare. Dec. 



Name — quercus, oak. Growing on oak. Fr. Hym. Eur. p. 623. Syst. 

 Myc. i. /. 423. Berk. Out. p. 263. C. Hbk. n. 875. .b". Mycol. Scot. n. 827. 

 — Ray Syn. t. \. f. 4. 



LXXVIII. Radtilum qicercinum. 

 Natural size. 



