354 



PLANT LIFE. 



it of neighboring cells, increasing until the sporangium 

 ruptures suddenly and the spores are shot out like projectiles. 

 In some cases the whole sporangium is thrown off in this 

 fashion, often to the distance of a meter or more (fig. 397). 



- n 



Fig. 399. 



C B 



Fig. 398. 



Fig. 398. — A, a fly killed by the fly fungus (Emf>nsa Muscce), stuck to wall by hyphaj 

 and surrounded by'a halo of the spores. Two-thirds natural size. B, hyphae projecting 

 into the air from the body of the fly, from whose tips spores are being shot off. 

 Several are shown in various stages of development. The turgor of the enlarged end 

 of hypha finally ruptures the attachment of the spore and it is shot off surrounded by 

 the mucilaginous contents which cause it to adhere to any object struck. Magnified 

 200 diam. C, a spore enveloped in mucilage. Magnified 420 diam —After Kerner. 



Fig. 399. — A, spore chain from a fructification Qecidium) of the cranberry rust 

 (Calyptrosftora). s, s, mature warty spores separated by an intermediate cell, z?v, 

 which has arisen by the division of the spore fundament by a transverse wall into a large 

 upper and a small lower cell. The upper becomes the spore and the lower the inter- 

 mediate cell which elongates, loses its contents, and dies ; its wall becomes mucilagi- 

 nous and so loosens the spores. Magnified 420 diam. — After Hartig. B, three spores 

 at tip of an acropetal chain ; the terminal spore therefore smallest. A disjunctor, d, 

 has been formed between the layers of the partition wall and has forced them apart. 

 The white area between two lowest shows area formerly connected. //, nucleus. 

 Magnified 520 diam. — After Woronin. 



The fungus which attacks and kills house flies in summer 

 casts off the single spore from the end of the stalk carrying 

 it by the bursting of the end of this stalk through excessive 

 turgor (fig. 398). With the spore goes the contents of the 



