XIL] NEW DISEASE OF GRASS. 63 



these flasks being enclosed in larger bladders termed 

 perithecia, and the whole embedded in the club-end or 

 stronia of the Torrubia. It is obvious that in the latter 

 position the sporidia are well protected by three different 

 enclosing walls, one within the other, and there can be 

 no doubt that these contrivances aid the contained spores 

 in tiding over vicissitudes of rain, drought, and frost during 

 winter. When the spring conies the stroma softens, the 

 mouths of the perithecia open, the asci sail out and burst, 

 and the chains of spores are set free in the air. These 

 chains speedily fall to pieces, as illustrated at J, enlarged 

 1000 diameters, and each fragment or sporidium on 

 germinating is capable of producing, not a Torrubia but 

 an Isaria. How small these numerous reproductive 

 bodies are may be judged from the fact that it would 

 require two hundred millions of them to cover a super- 

 ficial inch. Every plant of Torrubia ophioglossoides, Till., 

 sets free at least ten millions of these reproductive bodies 

 every spring. 



Before dismissing Torrubia ophioglossoides, Tul., a curious 

 fact regarding it may be mentioned. As it is parasitic 

 on an underground truffle named Elaphomyces muricatus, 

 Vitt, the question presents itself, How can the exceedingly 

 minute spores of the Torrubia reach the subterranean 

 truffle, buried, as it is, some four or five inches beneath 

 the ground, in places often thickly covered with brambles, 

 ferns, and moss ? The explanation of this phenomenon is : 

 The spawn from which the Torrubia springs grows in the 

 first instance, over a common moss named Mnium hornum, 

 Hedw., sometimes given as Bryum hornum, Sw., illus- 

 trated natural size at Fig. 23. The spawn or mycelium 

 of the Torrubia is yellowish, and when this yellow spawn 

 once fixes on the moss it goes from leaf to leaf, from stem 

 to stem, and from root to root, till sometimes a large 

 patch of this common moss is covered with the yellow 

 sticky threads of the curious Torrubia mycelium, which is 

 really now running from plant to plant in search of truffles. 



