102 PLANT-LIFE 



moment when the hyphse had it in their grip. The 

 hyphae are enabled to penetrate their host, and also 

 convert solid substances into liquids which they can 

 absorb, by means of an enzyme — a digestive ferment. 

 The advancing tip of a hypha secretes the enzyme; 

 this liquefies the cuticle, or cell-wall, and thus opens a 

 passage for the merciless and gluttonous parasite. If 

 the attacked Cress seedlings be kept for a while, under 

 proper conditions, the hypha? will bind all the seedlings 

 in the pot together in a thick felt, showing that the 

 Fungus is not satisfied with exhausting the seedling 

 first attacked; it will leave its dying host and seek 

 further victims among its healthier neighbours ; in fact, 

 it is not satisfied until all the seedlings in the pot are 

 exhausted. 



But amid these vegetative saturnalia Pythium is 

 not unmindful of the future. Having enjoyed a brief 

 and rapid existence at the expense of its host, with 

 the death of the latter, in the event of further victims 

 being unavailable, the mycelium must needs perish. 

 Hence steps are taken by the parent fungus, before it 

 has exhausted its host, to ensure that it shall at least 

 continue to live in the lives of its children. The indi- 

 vidual may be a mere detail and very mortal; but the 

 immortality of the race must, if possible, be secured. 

 In the case of Pythium the propagation of the species 

 is both asexual and sexual. In all Fungi, with the 

 exception of the Phycomycetes (Algal Fungi), to which 

 class Pythium belongs, sexual reproduction is not 

 generally admitted by botanists. Asexual reproduc- 

 tion is by means of zoospores and conidia. The spor- 

 angia, in which zoospores are developed, grow at the 



