PROTOPHYTIC AND OTHER FUNGI. 



325 



sexual spores; while the nutritive apparatus of these planis is composed 

 of an indefinite mycelium, which is a filamentous expansion (Fig. 207, 

 a), composed of elongated branching cells interlacing amongst each 

 other, but having no intimate connection; and this has such an indefinite- 

 ness of form, and varies so little in the different tribes of Fungi, that no 

 determination of species, genus, or even family, could be certainly made 

 from it alone. A true Generative process has not hitherto been detected 

 with certainty in these higher Fungi, although it has been supposed by 

 some observers to be carried on in the mycelium. And their Life -history 

 needs now to be carefully restudied, with all the assistance derivable 



Development of Myxomycetes : A, plasmodium of Didynium serpula ; B, successive stages, 

 , a', b, of sporosacs of Arcyria flava ; c, ripe spore of Physrtrum album ; D, its contents escap- 

 ing; E, F, G, the swarm-spore first becoming flagellated, and then amoeboid; H, conjugation of two 

 amoeboids, which at i have fused together, and at j are beginning to put out extensions and ingest 

 nutriment, of which two pellets are seen in its interior. 



from our increased knowledge of the simpler types of the group, and with 

 the skill which can only be acquired by considerable practice in Micro- 

 scopical investigation. The subject, however, is one of such peculiar 

 speciality, that it cannot be advantageously pursued further in a 

 Treatise like the present. 



322. Many eminent Botanists still rank in the Fungal series of Pro- 

 tophytes a very peculiar group, the Myxomycetes, the members of which 

 pass a large part of their lives in a state of what can scarcely be other- 

 wise described than as one of Animal existence. They grow parasitically 



