210 



BOTANY. 



sporangium, which may be distinct (Fig. 144, B], or it may 

 be a flattish, cake-like mass, the so-called cethalium, directly 

 derived from the plasmodium. In most cases the spore- 

 bearing masses contain internally, besides the spores, a 

 structure called the Capillitium, consist- 

 ing of thin-walled, spirally thickened, or 

 otherwise marked tubes variously disposed 

 (Fig. 144, C, cp). In some cases, where 

 there is a distinct sporangium, the pedi- 

 cel of the latter is continued into it as a 

 central column ; this is known as the Col- 

 umella ; it may send out branches which 

 support the walls of the sporangium. 



ma difforme (Didy- 

 mium Libertianum of 

 De Bary) coalescing or 

 conjugating. X 390. 

 After Cienkowski. 



(a) The following classification of the Myxomy- 

 cetes is by Rostafiuski.* He distinguishes seven 

 orders : 



Order I. Protodennese. Sporangia simple, of regular shape, not 

 possessed of a capillitium, with violet spores. 



Order II. Calcareee. Sporangia simple or compound, often pro- 

 vided with a columella, spores violet or violet brown ; whole fructifica- 

 tion, with more or less de- 

 posits of carbonate of lime. 



This includes many com- 

 mon species, under the 

 genera Physarum, Fuligo, 

 Didymium, Spumaria, etc. 1) 



Order III. Amauro- 

 chaeteae. Single sporan- 

 gium or aethalium, with- 

 out lime ; spores, capilli- 

 tium, and columella almost 

 always uniformly black, or 

 brownish-violet colored. 



In this order the genus 

 Stemonitis furnishes the 

 most common species. 



Order IV. Anemese. 

 Sporangium or setlialium 

 without capillitium or lime ; columella not evident, wall of sporan- 



Fig. 144. Fructification of Arcyria incarnata 

 (A. adnataof Ktfki.). -B, youug sporangium; C, 

 mature sporangium ruptured ; cp, capillitium; 

 p, wall of sporangium. X 20. After Sachs. 



* " Sluzowce Monografia" by Joseph Rostafinski, 1875. Zopf (" Die 

 Pilzthiere," 1884) extended the class so as to include many genera, e.g., 

 Vampyrella, Protomonas, Protomyxa, Plasmodiophora, etc., which 



