68 



BOTANY 



Reproduction is either by a division (mostly longitudinal) which may occur 

 while the cell is active, or it may first become encysted, after which the proto- 

 plast divides into two new individuals. 

 No sexual reproduction has yet been 

 certainly demonstrated for any of them. 



Affinities of Flagellata. The 

 Flagellata show affinities on the 

 one hand with the Infusoria, and 

 on the other with the lower 

 plants. The Volvocacese, which 

 are sometimes included with the 

 Flagellata, are forms which to 

 a certain extent connect the typi- 

 cal green plants with the true 

 Flagellata. The Myxomycetes 

 or Slime-moulds, the Brown Algae, 

 and possibly the Bacteria, also 

 show evidences of relationship 

 with the Flagellata, which are 

 thus seen to be a group almost 

 exactly intermediate between 

 the lowest animal and plant 

 forms. 



MYXOMYCETES 



FIG. 48. Flagellata. A, B, Chromu- 

 lina ovalis. A, active cell, showing 

 the single flagellum and the chromato- 

 phore, cr; B, encysted cell which 

 has just divided (X 1500). C. Euro- 

 glena volvox, a biciliatc form, with 

 chroma tophore (XlOOO). D, Scyto- 

 monas pusillus, individual dividing 

 (X2000). (A, B, D, after KLEBS; 

 C, after IWANOFF.) 



The Myxomycetes or Myce- 

 tozoa constitute another group of 

 organisms which exhibit both animal and vegetable characters. 

 Some of them are aquatics, apparently related to some of the lower 

 Flagellata, and perhaps to the Rhizopods among the Protozoa. A 

 second division, the Myxomycetes proper, or Slime-moulds, are not 

 aquatic, and develop a fruiting condition which is very similar to 

 that of the Fungi. 



The Myxomycetes receive their popular name of Slime-mould 

 from the vegetative condition, which is a large naked mass of proto- 

 plasm, or Plasmodium, of a slimy consistence, and usually whitish 

 or yellow in color. The best known of the Slime-moulds is JEthalmm. 

 septicum (Fuligo varians), which is especially common on spent tan- 

 bark, where the bright yellow plasmodia are sometimes very con- 

 spicuous. Slime-moulds, however, can usually be found in wet 

 weather, about rotten logs, decaying leaves, etc. 



The Plasmodium. The plasmodium shows active creeping movements, and 

 quickly spreads itself, in the form of a network, over the substratum on which 

 it is growing. It shows marked irritability, avoiding strong light, and seeking 

 moisture and food. Soft organic substances, such as a large Fungus, may be 



