^: 



UOW PLANTS GROW. 



Fi-. 11. 



Fi-. 12. 



together (¥'\g;. 4) ; one of these into two more (Fig. 5) ; and tljose repeating the 

 process by partitions formed in both directions (Fig. 0) ; forming a cluster or mass 

 of cells, essentially like the first, and all proceeding from it. After increasing in 

 number for some time in this way, and by a continuation of the same process, the 

 embryo begins to shape itself; the upper end forms the radicle or root-end, while 

 the other end shows a notch l)ctwcen two loi)es (Fig. 7); these lobes become the 

 cotyledons or seed-leaves, and the embryo, as it exists in the seed, is at length 

 comi>leted (Fig. 10). 



" 388. The tf iiowTii of the Plantlet when it springs from the seed, is oidy a 

 continuation of the same process. The bladder-like cells of which the embryo 



consists, multiply in number by the repeated 

 division of each cell into two. And the plant- 

 let is merely the aggregation of a vastly larger 

 number of these cells. This may be clearly 

 ascertained by magnifying any part of a young 

 plantlet. The young root, being more trans- 

 parent than the rest, answers the purpose best. 

 Figs. 11 and 12 are two small bits of the sur- 

 face highly magnified, showing the cells. And 

 if we make a thin slice through the young root 

 both lengthwise and crosswise, and view it 

 under a good microscope (Fig. 13), we may 

 perceive that the whole interior is made u|) of 

 just such cells. It is essentially the same in 

 the full-grown herb and the tree. 



" 389. So the plant is an aggregation of 

 countless millions of little vesicles, or cells 

 (Fig. 13), as they are called, essentially like 

 Mfpfe/^alllrJ^tlEnrrooilhlirr^'^'^"' the ccll it began with in the formation of the 

 Fig. 12.— A small portion, more magnified. embryo (Fig. 3); and this first Cell is the 



foundation of the whole structure, or the an- 

 cestor of all the rest. And a plant is a kind of structure, built up of these indi- 

 vidual cells, something as 

 Fig. 14. 



Fig. 13. 



Fig. 1.3.— One cell, like those of Fig. 14, detached. 



Fig. 1 1.— VieiT of a little cellular tissue of a rootlet, cut crosswise and 

 lengthwise. 



a bouse is built of bricks 

 — only the bricks or cells 

 are not brought to the 

 forming plant, but are 

 made in it and by it ; or, 

 to give a better comj)ari- 

 son, the plant is construct- 

 ed much as a honeycoml) 

 is built up of cells — only 

 the plant constructs itself, 

 and shapes its own mate- 

 rials into fitting forms. 



" 390. And vegetable 

 growth consists of two 

 things : 1st, the expansion 

 of each cell until it gets 

 its full size (which is com- 

 monly not more than -^l^ 

 of an inch in diameter) 



