MYXOGASTRES 17 



sporophores interlacing to form a dense mat concealing the substratum 

 and covering an area several centimeters square. Most common in 

 the tropics of both hemispheres. 



Var. porioides Alb. & Schw. {Ceratium porioides Alb. & Schw., 

 Consp. Fung. 359, 1805; Ceratiomyxa porioides (Alb. & Schw.) Schroet. 

 in Engler & Prantl 1 (i) : 16). Sporophores confluent, porose; pores 

 ample, angular, at length radiate-dentate. Ceratium crustosum Berk. 

 & Curt., Grev. 3 : 62, 1874, is merely a crustose form of this variety. 

 The var. porioides has frequently been regarded as a distinct species 

 and it ordinarily appears to be so, but cases occur in which it and the 

 typical form arise together from the same Plasmodium, hence the 

 attribution of a yellow Plasmodium to this variety cannot be regarded 

 as significant. Widespread and fairly common, but not so frequent 

 as the typical form. 



Var. ctzsia Jahn {Ceratiomyxa ccesia Jahn, Ber. Deutsch. Bot. Ges. 

 36 : 660, 1919) is similar to var. porioides, but tinged with green, and 

 developing from a bright blue-green plasmodium. It has been reported 

 only from Germany. 



Ceratiomyxa freyana Meylan (Bull. Soc. Vaud. Sc. Nat. 56 : 65, 

 1925) is described as arising from a bright yellowish green or citron 

 yellow plasmodium and as occurring in scattered small patches. In 

 other respects it seems not to differ from typical C. fruticulosa and 

 judging by the description is doubtfully distinct. It has been reported 

 from Switzerland and Rumania. 



Subclass MYXOGASTRES Fries ex Macbr. 



1829. Suborder Myxogastres Fries, Syst. Myc. 3 : 67. 



1833. Suborder Myxomycetes Link, Handb. der Gew. 3 : 405. 



1858. Class Mycetozoa de Bary, Bot. Zeitung 16 : 369, in part. 



1889. Class Myxogasteres Schroet., in Engler & Prantl 1 (i) : 8, in part. 



The slime molds included in this subclass are characterized by 

 abundant, minute, unicellular spores, enclosed in more or less per- 

 fectly denned sporangia and often accompanied by peculiar thread-like 

 or tube-like structures, free or variously attached and joined, forming 

 the capillitium. The spores on germination give rise either to swarm- 

 cells, or to amcebulae, which directly or by division give rise to swarm- 

 cells. After one or more divisions the swarm-cells function as gam- 

 etes, conjugating in pairs, the resultant amoeboid zygotes constituting 

 the young plasmodia. These feed voraciously, the nuclei dividing as 

 they enlarge. They also probably fuse with each other, and, when the 

 proper conditions arise, become transformed into the fructifications 

 typical of the several species. /CS^ 



