164; DeCandolles Vegetable Organographr/. 



" 5th. The cellules are endowed with the faculty of uniting together, of 

 absorbing the moisture around them, and probably of contracting and dilating. 

 They are round, or more or less elongated ; the former enclose the feculent, 

 mucilaginous, or resinous matters which they have elaborated, of which the 

 latter contain little or none. The round ones form the parenchyma ; the long 

 ones (by themselves in cellular plants, united with the vessels in vascular ones,) 

 compose the fibres or nerves. 



" 6th. The passages between the elongated cellules, or the vessels, appear 

 eminently to serve for carrying the lymph, i. e. the as yet unelaborated watery 

 juices. Those which are formed among the round cellules contain the more 

 stagnant juices. 



" 7th. The vessels, whatever their form, seem eminently intended to contain 

 air or gas, and are true aerial canals, at least in the ordinary course of vege- 

 tation. 



" 8th. Certain particular points of the surface of plants, and especially of 

 vascular ones, are more eminently endowed with the faculty of absorbing water. 

 They are called Spongioles, and are situated at the extremity of roots, at 

 the top of the style, and on the surface of seeds. 



" 9th. Dilatations of the intercellular passages, or, in certain cases, rup- 

 tures of the cellules, cause irregular cavities in the interior of the tissue. 

 These receive the name of Air Cavities when filled with air, or of Receptacles 

 of proper Juice when they contain an elaborated juice. 



" 10th. Glands or glandular surfaces are some of them composed only of 

 cellular tissue, others of cellular tissue and vessels ; both secrete special juices, 

 but the first appear (at least in certain floral organs) to be excrementitial, and 

 the second recrementitial. 



" Uth. 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 situated upon the nerves, whilst 

 the stomata are always upon the parenchyma. 



" 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. 



" 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. 



" 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 develope- 

 ment 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. 



" 13th. The stem of vascular plants is sometimes cylindrical, composed of 

 a single system (the Woody Body), which increases by the developement of 

 new fibres internally ; sometimes conical and composed of two systems (the 

 Woody Body and Bark), which increase in diameter by means of layers, 

 which are developed upon the surface of each of these systems which is in 

 contact with the other system. To the first the name of Endogens is given, 

 to the latter that of Exogens. The structure of the root of each class is 

 similar to that of the stem. 



" 16th. The stem of vascular plants is furnished laterally with appendicular 

 organs, which seem formed by the expansion of one or more fibres. 



" 17th. These appendicular organs, although very different from one another 

 in their appearances and uses, seem, however, entirely identical in their original 

 nature. 



• " Those which are already formed in the embryo, bear the name of Coty- 

 ledons or Seed-leaves ; those which are produced immediately afterwards. 



