140 



STRUCTURAL BOTANY 



in the stomata of flowering plants. Beneath each stoma 

 is an intercellular space (Fig. 64). It is remarkable to 

 find these organs so perfectly differentiated in plants 

 like the Mosses, which in all other respects are so 

 remote from the higher groups. There is one Liverwort 

 (Anthoceros) which also has well-formed stomata on the 

 fruit. It is worth noting that typical stomata have in 

 no case so far been found in the sexual generation ; 

 when the oophyte bears organs 

 with the same function (as in 

 certain Liverworts), they are 

 constructed on a totally different 

 plan. 



It is evident from the anatomi- 

 cal structure that the sporophyte 

 is capable of obtaining a great 

 part of its food for itself, and this 

 has been proved experimentally 

 to be the case. So far as the 

 assimilation of carbon is con- 

 cerned, a sporogonium such as 

 that of Funaria is able to provide 

 for itself, from the time when its 

 assimilating tissue is developed. Water, with the 

 mineral food-substances, is necessarily supplied through 

 the stem of the Moss plant, and passes up to the 

 capsule through the seta, which contains a central 

 conducting cylinder, like that of the stem itself. The 

 cortex of the seta consists of thick-walled tissue, and 

 serves to give the mechanical strength necessary to 

 enable this slender stalk to support the weight of the 

 capsule. The bottom of the seta is fixed in the tissue 

 of the oophyte by a conical foot, but although the 



FIG. 65. Stoma of Funaria 

 in surface view, p, the 

 pore. Note the nuclei 

 and chlorophyll-granules 

 of the fused guard-cells. 

 Magnified 630. (After 

 Haberlandt.) 



