Il8 MINNESOTA BOTANICAL STUDIES. 



Gerard (90. p. 114) states that what Schweinitz described is an 

 insect gall. The Minnesota specimens are undoubtedly of fungous 

 origin and have all the appearance of a Rhytisma. although no asco- 

 phores are apparent. 



Exsiccati : Ellis & Everhart. North American Eungi. 3044. 

 5. Rhytisma punctatum (Pers.) Fries. Vetensk. Akad. Handl. 104. 

 1819. 



Xylo)na punctatum Pers. Syn. Meth. h'ung. 1801. 



Stroma forming minute spherical or irregular black bodies crowd- 

 ed together on a yellowish patch, on upper surface of the leaf, up to 

 I cm. in diameter, each stroma up to i mm. in diameter; spores 

 not present. 



On upper surface of leaves of Acer spicatnm; Cook. Aug. IQ03, 

 Em. & B. 177. 



Exsiccati : Ellis & Everhart. North Am. Eungi 1776; Jaczewski 

 Eungi Ross. 288. Plates : Tubeuf and Smith, Diseases of Plants, p. 

 244. fig. 129. 



Order Tuberales. 

 Family VII. Eutuberaceae. 



Alycelium and fructification wholly within the substratum, never 

 coming to the surface, globose or oval or irregular. 



I. TUBER. 



Ascomata (closed cups) spherical or oval, smooth, or minutely 

 areolate, peridium thin cartilaginous ; gleba veined then lacunose, 

 but never powdery ; asci short, 4 spored. sack-like ; spores oval, hya- 

 line, continuous. 



I. Tuber dryophilum Tulasne, Fungi Hypogaei 147. tab. 5. f. 3. tab. 19. 

 f. 8. 1851. 



Tuber horchiamim Zobel. in Corda, Icon. fung. 6: jy. 1854. 



Tuber borchii Corda, Icon. Eung. 6. tab. 19. f. 137. 1854. 



Ascomata globose or elliptical, irregular. 0.5-1.5 cm. in diameter, 

 firm, smooth, light watery gray; peridium thin; gleba fleshy but 

 firm, white; asci nearly globular, sessile, generally 4 spored; spores 

 spherical to broadly oval, distinctly reticulate. 20-30 x 30-45 mic. or 

 about 30 mic. when spherical. 



In black moldy soil ; Cook, Aug. 1903, Ereeman & Ballard 48. 



Exsiccati : R. Thaxter, Kiltung Point. Maine, Sept. 1902. 



