INTRODUCTION. 



their stalks, they are called Stipules. When connected with 

 the flower or its stalk, they are called Bracteas. Leaves ag- 

 gregated together and surrounding the flower at some distance 

 form an Involucre, or when closely investing the flower, a Calyx. 

 Delicate leaves immediately within the calyx constitute the 

 Corolla. Within it, leaves modified so as to resemble filaments 

 with an enlarged part at the end, form the Stamens ; and in 

 the centre of the flower, modified leaves enclosing seeds, are 

 the Carpels, singly or collectively forming Seed-vessels or 

 Pericarps, which at first are named Ovaries. Thus all the 

 organs attached to the stem are modified leaves. 



OF THE HOOT AND ITS DIFFERENT KINDS. 



The Root is that part of the plant which is commonly im- 

 mersed in the ground. It consists of two parts, the Body of 

 the root, and the Radicles or Fibres. The latter are small 

 branches or thread-like organs which come off from the body, 

 and are the only essential parts of the root, it being by their 

 spongy extremities that nutritious matter is absorbed from the 

 soil. The uses of the root are to fix the plant in a particular 

 place, and to imbibe nourishment for it. The following are the 

 principal varieties of the root : 



A Fibrous Root (Fig. 1.) consists entirely of fibres or radicles, 

 which may be undivided or branched. 



A Creeping Root (Fig. 2.) is a kind of subterranean stem, 

 running horizontally, and throwing out fibres at intervals. The 

 fibres are the true roots ; but although the body may be called 

 a stem, it is also analogous to the body of a root, and in fact 

 gives off stems, as in Mint. 



A Tapering or Spindle-shaped Root (Fig. 3.) is a thick- 

 ened, fleshy root, tapering downwards, and sending out small 

 fibres. 



A Tuberous or Knobbed Root (Fig. 4.) consists of fibres to- 

 gether with one or more fleshy knobs, varying in form, and 

 which are, properly speaking, subterranean reservoirs of nutri- 

 tious matter for the development of the stem and leaves of next 

 year. The true Tuber, however, as that of the potatoe, is a 

 fleshy subterranean stem, having buds in it, which on being 

 developed become stems. 



An Abrupt Root (Fig. 5.) is a kind of fleshy root, having an 

 elongated form, and looking as if it had been bitten off at the 

 lower end. 



