> THE CANE. 



of intermediate size ; 20, chloroplast in one of the cells of the lower epidermis ; 

 21, one of the stomatic openings that are abundant on the lower surface of the leaf; 

 this one is closed, an open one may be seen at 25-26 ; 22, accessory (?) cell of the 

 stomatic opening; 23, one of the smallest fibre-vascular bundles ; 24, one of a group 

 of cells very rich in protoplasm which extends between the vascular bundles, the 

 nearer these cells are to the lower epidermis the denser their protoplasmic contents ; 

 25-26, protoplasts in the guard cells of the stomatic opening ; 27, one of the sieve 

 tubes, among these sieve tubes may be seen the smaller companion cells and their 

 protoplasts ; 28, extra chlorophyll-bearing cells outside the single layer surrounding 

 the vascular bundle; 29, lip of one of the stomatic guard cells; 30, cell rich in 

 protoplasm, of the same class as 24 ; 31, nucleus of one of the companion (?) guard 

 cells ; 32, fibro-vascular bundle of small size ; 33, apparently a locule in the 

 thickened portion of the wall of the stomatic guard cell ; 34, entrance between the 

 guard cells of the stomatic opening ; 35, cuticle of the lower surface of the leaf ; 

 36, fibro-vascular bundle of intermediate size ; 37, 37, 37, air chambers immediately 

 above the stomatic openings. Throughout the illustration the nuclei are shown 

 grey, and the nucleoli black. The tissue represented at 24 and 30 is probably 

 primary leaf-tissue, from which during the growth of the leaf the various tissues 

 represented have been differentiated." 



Function Of the I^eaf. In a sense the leaf may be termed the 

 manufactory of the plant ; under the influence of the chlorophyll and in direct 

 sunlight starch is formed from water and carbon dioxide ; other transforma- 

 tions occur, and the material passes down to be stored in the stem as sugar. 

 The stomata serve for the respiration of the carbon dioxide, and for the 

 secretion of the waste products of the plant; the fibre, or sclerenchyma, as 

 in the stem, gives rigidity to the leaf. The leaf in its early stages is rolled 

 up, and is opened by the expansion of the motor cells ; in dry weather these 

 cells contract and cause the leaf to roll up, thus exposing a less surface for 

 evaporation. 



Structure of the Root. In Fig. 6 is shown to a scale of 1^ 

 the end of one of the roots growing from the zone of adventitious roots 



in that part of the stem of the cane below 

 ground. Towards the end of the root are seen 

 ^ ' ^ N numerous very fine hairs, and at the extreme 



end is seen the root cap. In Figs. 7 and 8 



Ji ^^^^V "iii^H^ are Si vea longitudinal and cross-sectional views 

 of the root, the longitudinal view being taken 

 through the apical point ; re is the root cap, m is 

 FIG. 6 - the layer of meristematic tissue, rh a root hair 



formed from the piliferous layer on the extreme outer layer of the root ; cor 

 is the cortex, st the central cylinder, v a developing wood vessel, and x a 

 larger wood vessel. 



The root cap on the exterior consists of dead cells, and is continually 

 being renewed from the interior by the layer of meristematic tissue from 

 which also arise by a continual process of cell sub-division all the other 

 tissues of the root. 



