CIIYPTOGAMIA FUNGI. 137 



thin epidermis .by a slit in the centre. PERS. Syn. 102. MOUG. 

 and NEST. No. *]5. 



Hob. On dead cones of Scotch fir, very common. 



Confined to the upper and exposed part of the scales. Very 

 often there is nothing visible, except numerous minute 

 black points penetrating the epidermis ; but some of our 

 specimens have the character of an Hysterium more evi- 

 dently than those given in the work of MOUG EOT and 

 NESTLER. It is surely not distinct from Sphceria sirobilina. 



71. SCLEROTIUM. 



OBS. Mr PURTON, in his Midland Flora, iii. 319, says that 

 Sclerotium durum in habit and substance does not appear to differ 

 from our Rhytisma salicinum, an opinion which may provoke a 

 smile from the professed Mycologist, but which I am inclined to 

 think is not far from the truth. Sclerotium differs from Rhytis- 

 ma scarcely in any thing but in form, and that may depend on 

 differences in their place of growth. 



1. S. durum, adnate, dull black, oblong or linear-oblong, promi- 

 nent, substriate; internally white. PERS. Syn. 121. HOOK. 

 Scot. ii. 10. GREV. Crypt. Fl t. 1. FL Edin. 4G2. 



Hob. On the dead stalks of the potato, and of umbellife- 

 rous plants, in winter, common. 



Originates beneath the epidermis, but soon becomes exposed. 

 There is sometimes the appearance of a cleft down the 

 middle, when the plant much resembles an Hysterium. 



2. S. semen, very black, globular or nearly so, free, roughish or 

 corrugated; internally white. PERS. Syn. 123. GREV. Crypt. Fl. 

 t. 144. f. 2. S. Brassica, Sow. Fung. t. 393. f. 3. 



Hob. On rotting potato stalks, and on the stalk of a thistle, 

 late in autumn, not common. 



Our specimens were like small peas, of a darker colour than 

 those figured by Dr GREVILLE. The fungus, however, is 

 said to be pale when young, assuming in its progress a 

 reddish, and at length a black hue. It easily parts from 

 its hold, and is apt to fall off in drying. 



.3. S. pustula, scattered, dull black or brown, roughish, round, 



