286 



BOTANY. 



ogonium by the growth of many basal enveloping branches, 

 and inside of this the carpogonium increases in size, and 

 sends out branches, which finally produce eight-spored asci. 

 The little tuber-like mass thus formed is yellowish, and of 

 the size and appearance of a coarse sand grain. 



(a) Aside from Penidllium, we have in this country very few repre- 

 sentatives of this order. Two or three species of Thiber have been 



recorded, and two of Elaphomy- 

 ces.* 



(b) In Europe, where they grow 

 abundantly, Tuber cestivum, T. 

 melanospofum, and T. luagnatum 

 are gathered for food. They are 

 found by the aid of dogs and pigs, 

 ■which are trained to search for 

 them. 



379. — Order Helvellacese 

 (or Discomycetes). These 

 are for the most part disc-like 

 or cup - like saprophytes, 

 which frequently attain large 

 dimensions. The hymenium 

 is spread over the upper and 

 generally exposed surface of 

 the full-grown plant, which 

 is in reality the sporocarp. 



In Peziza, one of the prin- 

 Fig.i94.-seznai organs of ft.fea.o«- cipal genera, the sexual or- 



nveiia, highly magnifled. A, at time of ganS OCCUr On the mycolium 



fertilization; a, carpogonium ; /, iricho- 6 . i .n 



gyne ; i, anth. ridium. B, after fertiliza- on Or in the ground : the 

 tion ; A, A, the hyj)h8B from which the re- , „ , . , , ,, 



ceptacle is developed.— After Tulasne. ends 01 certain hyphse SWCll 



up into ovoid vesicles, the carpogonia (Pigs. 194 and 195), 

 each of which is provided with a more or less bent and 

 curved appendage, the trichogyne (Fig. 195, and/,/. Fig. 

 194). From below the carpogonium a branch grows out, 

 and, curving around, becomes closely applied by its tip to 

 the extremity of the trichogyne (Figs. 194 and 195). The 



* See Bulletin of the Torrey Botanical Club, November, 1878, for the 

 species of Tuber discovered in North America. 



