GENERAL SUMMARY. 311 



and vessels ; both secrete special juices, but the first appear 

 (at least in certain floral organs) to be excrementitial, 

 and the second recrementitial (Book i. Ch. 9). 



11th. The surface of plants exposed to the air is often 

 invested with Hairs, which are prolongations formed of 

 projecting cellules. Some of these hairs are protecting 

 organs for the surfaces ; the others the supports or 

 canals of excrementitial glands. They are always situ- 

 ated upon the nerves, whilst the stomata are always 

 upon the parenchyma (Book i. Ch. 6 and 10). 



12th. A vascular plant, considered lengthways, is 

 composed of two bodies opposed by their bases (stem 

 and root), and which grow in a contrary direction to one 

 another. Their point of junction is called the Neck 

 (Bookii. Ch. 1, 2). 



13th. The body which descends, or the Root, elongates 

 indefinitely by its extremity alone; does not become 

 green by the action of the sun, except at its extremity ; 

 bears neither leaves nor flowers, and serves to fix the 

 plant in the ground and to draw up its nourishment 

 (Book ii. Ch. 2). 



14th. The body which rises upwards, or the Stem, 

 elongates throughout its whole length till the period 

 when it ceases to grow, unless by the development of a 

 body resembling itself (branch) and which is grafted 

 upon it. It becomes green on exposure to the light 

 throughout its whole length, at least in its young state, 

 bears leaves and flowers, and transmits to them the 

 nutriment absorbed by the roots (Book ii. Ch. 1). 



loth. The stem of vascular plants is sometimes 

 cylindrical, composed of a single system (the Woody 

 Body), which increases by the development of new 

 fibres internally ; sometimes conical and composed of 

 two systems (the Woody Body and Bark), winch 

 increase in diameter by means of layers which are 



