CHAPTER II. 



PLANT LIFE 



Most plants consist of shoot and root systems, the former 

 ascending, seeking the light, bearing branches, leaves, flowers, 

 and fruits ; the latter descending and avoiding the light. The part 

 at which the tw r o diverge is popularly known as the " collar. ' r 

 Some plants have one or more of these parts wanting, but it is 

 unnecessary to consider these here. 



The roots (descending axis) hx the plant in the soil or 

 substratum ; they absorb nutriment in a fluid state from the soil 

 and in many cases act as reservoirs of food stored for the growth 

 of a succeeding season, e.g., Yams, Carrot, Dahlia and other 

 tuberous-rooted plants. To enable the roots to penetrate the soil 

 without injury, their delicate tips are protected by root-caps. In 

 most plants these are very minute, but in some they are large 

 and plainly seen ; in the thick hanging, aerial roots of the Screw- 

 pines (Pandanus) the root caps are very large, and can be pulled 

 off by hand. Towards the ends of the roots root-hairs are 

 produced ; these apply themselves to the particles of the soil, and 

 by means of the acid fluid permeating their thin cell walls, they 

 dissolve ingredients which they absorb and then use in the nourish- 

 ment of the plant. 



The shoot or stem (ascending axis), generally arising above the 

 surface of the ground, exposes the leaves and other appendages 

 to the full influence of light and air, conducts the necessary mineral 

 substances from the roots to the leaves, and also the food supply 

 from the leaves to the roots. Stems are erect (as in trees), climbing, 

 by hooked spines, tendrils, etc., (as in Calam is and Vines), twining 

 (as in Ipomoea), creeping (as in Sweet-potato, Pepper, Vanilla, etc.), 

 or underground (as in Ginger). Underground stems (known as 

 rhizomes] superficially resemble roots, but can be distinguished by 

 their possessing rudiments of shoots and leaves in the form of 

 scales with buds in the axils. Ordinary stems are of two types, 

 dicotyledon and monocotyledon. The former represent the majority 



