26 



HUTCHINSON'S POPULAR BOTANY 



FIG. 44. STAB-SHAPED CELLS OF COMMON BEAN. 



plant, but of the Common Bean 

 (Vicia faba), are fairly uniform. 

 The solitary stellate cell in the 

 next figure (fig. 45) is not so regu- 

 lar. It is a Desmid one of a 

 remarkably beautiful family of 

 unicellular Algce. Good examples 

 of stellate cells are also afforded 

 by the stems of the Common 

 Rush (Juncus effusus, fig. 46), as 

 well as by the Flowering Rush 

 (Butomus umbellatus), whose hand- 

 some rose-coloured flowers, rising above the 

 surface of the water on a stalk three or four 

 feet high, make it deservedly a favourite 

 with lovers of British water-plants (fig. 51). 

 Of more than morphological import- 

 ance are the facts to be next noticed. 

 "Endlessly diversified in the details of 

 their form and structure," says Professor 

 E. B. Wilson in his fine work on the vege- 

 table cells, " these protoplasmic masses 

 nevertheless possess a characteristic type 

 of organism common to them all ; hence 

 in a certain sense thej T may be regarded 

 as elementary organic units out of which 

 the body is compounded. The composite 



structure is, however, character- 

 istic of only the higher forms of 

 life. Among the lowest forms 

 at the base of the series are an 

 immense number of microscopic 

 plants and animals, familiar ex- 

 amples of which are the Bacteria, 

 Diatoms (fig. 49), Rhizopods, and 

 Infusoria, in which the entire 

 body consists of a single cell, of 

 the same general type as those 

 which in the higher multicellular 

 forms are associated to form one 

 organic whole. Structurally, 

 therefore, the multicellular body 



FIG. 46.-STAK-SHAPED CELLS FROM STEM OF is . in ^ certain sense comparable' 

 COMMON RUSH. with a colony or aggregation of 





FIG. 45. A DESMID. 



One of the simplest forms of green plants. 



