OF AGRICULTURE. 17 



(bran); the starchy part within the "bran," and sur- 

 rounding the gemij is called the albumen. The integu- 

 ment and albumen together form the seed-lobe. When 



3 



a seed consists of only one lobe, it is called a one-lobed 

 plant, as Indian corn. If the seed has two lobes, as- 

 the bean, the plant is called a two-lobed plant. 



The stems of plants whose seeds have only one 

 lobe, increase in size by internal growth. Such plants 

 are called endogens'. The stems of plants whose seed 

 have two lobes, generally grow by the formation of 

 layers on the outer part of the stem, immediately 

 beneath the bark, or by external growth. These are 

 called exogens. The grasses, wheat, corn, palms, and 

 plants generally having the veins of their leaves par- 

 allel, are endogens. Beans, peas, and the trees and 

 shrubs of our forests are exogens. 



Tissues of Plants. The various organs of plants are 

 composed of different kinds of structure, called tissues. 

 These are made up of fibre or membrane; or both 

 together. There are five kinds of tissue : first, cellu- 

 lar tissue ; second, woody tissue ; third, vascular tis- 

 sue ; fourth, vasiform tissue; fifth, laticiferous tissue. 

 Cellular tissue is composed of minute cells, resting 

 upon and pressing against each other, so that the sidc^ 

 where they meet become flattened, and give to the 

 cell a somewhat regular form. Woody tissue lias a 

 fibrous structure, the fibres being in the form of slen- 

 der tubes overlapping each other at their extremities. 

 It is this structure which gives strength to wood, and 

 various kinds of fibrous materials used in the arts, 

 such as flax, hemp and cotton. Vascular tissue 

 resembles the woody in external form, but (lifters in 

 having a long, slender fibre coiled within it from end 



