CHAPTER XXX. 



SCHIZOPHYTA. 



Under the general name of the Schizophyta a vast number of minute 

 organisms have been included, which have multipHcation by fission 

 as a common feature. The closeness of their affinity is, however, a 

 question of some doubt. Some of them possess colouring matter of a 

 bluish-green or pink tint, and are therefore distinguished as Fission- 

 Algae, or Cyanophyceae. In others such colouring is wanting in the 

 protoplast: they are distinguished as Fission-Fungi, or Bacteria. 

 These are among the simplest of organised plants, and include the 

 most minute of living beings. They stand rather isolated from the 

 other Thallophytes. Most of them have more or less gelatinous walls, 

 surrounding a protoplast in which, though granules of chromatin 

 may be detected, there is no fully organised nucleus. Sexuality is 

 absent. But in contrast to this simpHcity of structure and life-history 

 they show the greatest possible variety 

 of physiological activity, and this is ^^ — -x^ 

 especially so among the Bacteria. ( ,',/fS^\V\ C 



Cyanophyceae. 



The blue-green Algae are unicellular, 

 or filamentous. They are found living 

 either in water, or on surfaces which are 



' ^ Fig. 389. 



habitually moist. A common type is Gloeocapsa polydermatica. A, inpro- 



. ^ , , ^1 . cess of division ; B, to the left, shortly 



seen m GtoeOCapSa, where the oval or after division; C, a later stage. 



spherical cells have a swollen cell-wall. ''^'^°' 



This holds the cells together after fission, in rounded colonies which 

 break up by disorganisation of the wall. It is commonly found on 

 the inner surfaces of the glass of damp greenhouses (Fig. 389). 



456 



