HOW PLANTS LIVE AND WORK. 325 



What flowers are, and what is their function, what are the ser- 

 vices which bee and butterfly come so readily to perform, we 

 shall see later. 



II. — The Reproduction of a Flowering Plant. 



We have seen that a green plant gets through a tremendous 

 amount of work. The tiniest leaflet at the summit of the highest 

 forest-tree is constantly being supplied with weak watery solutions 

 which the tree has raised, by some mysterious means, from the 

 ground. At the caprice of every breath of wind, the leaflet is yet 

 throughout the day performing chemical operations of the highest 

 degree of complexity and importance. These operations depend 

 upon the activity of the living matter of the tree. Every plant is 

 made up of cells and the products of cells, and every living cell 

 contains a viscid substance called protoplasm, which Huxley, in a 

 happy phrase, termed " the physical basis of life." So far as is 

 known, protoplasm is the only living matter in creation. It is by 

 the activity of the protoplasm of its cells that the plant is able to 

 build up, from air and soil, those complex substances which are 

 so vitally necessary to us. 



Now, all this work is, in a sense, purely selfish. It is per- 

 formed for the benefit of the individual plant, and would of itself 

 soon come to nought. It seems to be an inexorable law of Nature 

 that everything that lives must, sooner or later, die. Why this 

 should be so, is not very clear ; but it is evident that if plants are 

 not to become altogether extinct, they must of necessity devote 

 part of their energies to producing new individuals, and to sending 

 them forth into the world as well equipped as possible for the 

 battle of life. It is with this unselfish and self-sacrificing side of 

 a plant's life-work that we must now deal. 



Take another Wallflower and examine the blossom closely. 

 There are evidently at least eight leaves in the flower, but, unlike 

 the green " foliage " leaves, these are not arranged spirally on 

 the stem, but are inserted at nearly the same level. The most 

 external leaves are four in number, small, narrow, and purplish in 

 colour. Each of these leaves is called a sepal, and the four sepals 

 together constitute the calyx of the flower. Notice carefully that 

 two opposite sepals are bulged out at the bases, forming pouches, 



International Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. x 



