28 A Monograph of the Myxogastres. 



MYXOGASTRES (FRIES). 



MYXOGASTRES, Fries, Syst. Myc., iii. p. 67 (1829) ; Schroeter, 

 Kr. Fl. Schles., Vol. iii. p. 98. 



MYXOMYCETES, Wallr., Fl. Crypt., ii. p. 333 (1833) ; Cooke, 

 Brit. Myx., p. 1 ; Raunk, Myx. Dau., p. 20 ; Sacc., Syll., Vol. vii. 

 pt. i. p. 323. 



MYCETOZOA, De Bary (Die Mycetozocn, 1864); Rost. (Mon. 

 Sluzowce) (in part). 



PILZTHIERE, Zopf, in Schenk's Handb. der Hot., Vol. iii. 

 (1884) (in part). 



Consisting during the entire vegetative period of an accumula- 

 tion of naked cells forming a plasmodiiim possessed of the power 

 of movement, and invested with an imperfectly differentiated, 

 yielding membrane. This plasmodium at length becomes trans- 

 formed into sporangia containing numerous spores which form 

 a powdery mass at maturity. First product of spores on 

 germination either ciliated zoosporcs or amoeboid cells, which 

 after repeated bipartition and conjugation, combine to form a 

 plasmodium. 



The species are usually aerial, the plasmodium stage being 

 passed in rotten wood or amongst decaying vegetable matter, 

 and coming to the surface only to form the sporangia ; never- 

 theless several species have been observed to pass the whole of 

 their existence under water. The sequence from the aquatic to 

 the aerial condition may frequently be seen in the same batch 

 when developing on logs that are partly submerged. 



The most pronounced feature in the evolution of the Myxo- 

 gastres is in connection with spore dissemination, and the 

 following arrangement is based on the relative development of 

 the capillitium, which is seen in its most perfect form in the genera 

 Trichia and Arcyria. In the Gastromycetes I have shown else- 

 where J that the sequence of evolution all tends towards securing 

 in the most efficient manner, the dissemination of the spores ; 

 commencing with the subterranean genera Rhizopogon and 



1 A Monograph of the British Gastromycetes. Ann Bot., Vol. iv. pp. 

 1103 (4 plates). 



