14 



Principles of Plant Culture. 



im 



B 



TO 



of numerous little sacks or cav- 

 ities, more or less clearly defined, 

 called cells. Cells from different 

 beings, or from different parts 

 of the same being, may vary 

 much in form and size, but they 

 are seldom large enough to be 



. shows a plant g^^^^ ,,j. ^j^^ ^^^^^^^ ^^^^ ^^ 

 ncinp: to divide ^ 



Fig. 1. Showing four indi- 

 vidual plants of a species of Seen without magnifying power. 



Prr:tii(;,cciix. A sh 



before commencing 



into other plants. B, c and D animal.s consist of single cells 



show how the cells divide to /-lt;™ -t \ o ^c xi „ i.^,„ 



, ., ,*„,,, {bis. 1). teome 01 the lower 



form other plants, "'"V-i^' v ^ y ^ 



magnified. 



Highly "^^ S'' ^J' 



plants consist of a single row of 

 cells unit(^(l at the ends (Fig. 2). The higher plants 



Fi<i. 2. Part of a filament of a species of Spirof/i/rrt, a plant consisting 

 of a single row of cells united at their ends. The places where the cells 

 join ar(.' indicated by the vertical lines. Highly magnified. 



and animals are made up 

 of many cells united, and 

 in these, the cells assume 

 different forms and prop- 

 erties in the different or- 

 gans (Fig. 3). In some 

 cases the united cells may 

 be readily separated from 

 one another, which shows 

 each cell to be more or 

 less an independent struct- 

 ure. As a rule, each cell 



s^QoSsos 



Fig. 3. Showing cells of the apple leaf 

 is surrounded by its own in a section from its upper to its lower 



surface. Highly magnified. The spaces 

 Closed cell-'VVall. marked I are cavities between the cells. 



