26 PRIMARY DIVISIO;,'.>; ETC. 



slightest pressure tliis fluid is injected tlu-ough the tube into lhe 

 wound made by its point. E:iJ^ nettle) 



43. Prickles (Fig. 3)fare also expansions of the epidermis, 

 consisting of hardened cellular tissue (29, e)j; They are appen- 

 ded to the cuticle alone, and are stripped off with it. . Unlike 

 the tkor7i (171), they have no connection with the wood, nor do 

 they disappear by cultivation,- :Ex. rose, bramble^; (Rubus.) 



44. Glands (Fig. 3)T9re minute bodies of cellular tissue, situ- 

 ated on various parts of the plant.Jgenerally serving to elaborate 

 and discharge its peculiar secretions, which are oily, resinous, 

 saccharine, acrid, &c. 



a. Tliey ai-e either sessile, as in tlic cassia; or mounted upon a stipe, as in the 

 passion flower; or imbedded in the leaf, causing it to appear jnmctate, as in the 

 leaf of the lemon. Often the gland appears to be merely the expansion of a hair, 

 either at its base or its summit. Such are called glandular hairs. 



45. Analogous to glands, are those cavities formed in the cel- 

 lular tissue^ to serve as receptacles of secretion:^ Examples are 

 seen in the rind of the orange and lemon, containing minute 

 drops of a fragi-ant volatile oil. Tlie turpentine of the tir balsam 

 is stored up in large reservoirs of tliis kind. 



CHAPTER III. 



PRBIAKY DIVISIONS OF TEE VEGETAELE KINGDOM. 



46. The vegetable kingdom has long been considered by 

 botanists under ;two^ great natural divisions, namely, PHiENOGA- 

 MiA, or Flowering Plants, and Cryptogamia, or Flowerless 

 Plants. , • 



47. Besides the obvious distinction made by the presence or 

 the absence of the flower, these divisions are further distin- 

 guished by their structure. The PliEenogamia abound with the" 

 ligneous and vascular tissice, while the Cryptogamia consist 

 more generally of the cellular. Hence, the former are also called 

 Vasculares, and the latter Cellulares.; 



