PROPAGATION OF PLANTS. 15 



product of other cells, or some form of organizable matter 

 containing the elements of which the cell is composed. 

 At 6rst the cell consists of a separate membrane, but as 

 growth commences there is a re-arrangement of the 

 formative matter, varying according to the characteristics 

 of the plant in the course of development. In some of 

 the lower forms, as has already been stated, the fully 

 developed plant consists of a single cell, others of only 

 an aggregation of the same or closely allied forms; but as 

 we pass upward, the structure becomes more complicated, 

 and there is a greater variety in the shape of the cells, as 

 well as in the elements of which they are composed. 

 The cells have the power of multiplication, new cells 

 springing from the mother cell ; these in turn producing 

 others, and in plants like the common puff ball, many 

 millions are produced in a few hours. Dr. Lindley cal- 

 culated that in one gigantic species, the Bovista Gigantea, 

 that the cells were produced at the rate of sixty-six mil- 

 lions in a minute. But in such simple kinds of plants 

 as the mushrooms and sea-weeds, the entire structure is 

 composed of what is called cellular tissues, a pulpy mass 

 very similar to that which makes up the bulk of our 

 cultivated fruits and vegetables. Some cells elongate to 

 a great length and become a continuous hollow tube, as 

 in the filaments of Cotton, or solid fibers, as in the inner 

 bark of the Basswood and Papaw tree, or in 'such herba- 

 ceous plants as the Ramie, Hemp, Jute and other fiber- 

 yielding species. There is a wide difference in the way 

 cells are united. In some of the lower orders of plants 

 the cell walls separate as they form, but in the higher 

 and more complex, the walls of the young cells are solid 

 and only divide or split apart as they advance in age. 

 In many of the simple plants, the cells are widely sepa- 

 rated and the intervals between them is filled with a semi- 

 liquid mass, in which nothing that resembles a cell can be 

 discovered. But as we advance to the higher orders of 



