70 APPENDAGES OF PLANTS. 



an under-shrub, and when the stem is not woody, dying down to the 

 root annually, it is called an herb. 



Appendages of plants. These are stipules, thorns, prickles, glands, 

 scales, stings, tendrils, pubescences, bracts, hairs, etc. They are found 

 on various species of plants ; and, although their functions are not 

 perfectly known, yet no one can doubt their importance in vegetable 

 economy. Stipules are membranes, or leafy scales, commonly in 

 pairs at the base of the leaf on either side of the foot stalk, in most 

 plants, as in the sweet pea. Prickles arise from the bark and are 

 generally found on the stem, as in the rose ; sometimes on the base of 

 the leaf, or petiole, as in the raspberry, on the calyx, or on the berry, 

 as in the gooseberry. They are straight, hooked, or forked. Thorns 

 grow from the woody part, where they remain when the bark is 

 stripped off, while prickles come off with the bark. They often dis- 

 appear when the plant is cultivated. Some think them bulbs which 

 by cultivation form branches. Glands are small globules containing 

 a liquid secretion which, it is thought, give the odor of some plants. 

 They are sometimes at the base of leaves, sometimes in the leaves, as 

 in the lemon and myrtle, or they may be on other parts of leaves, and 

 also on the ends of hairs, as in the moss rose, nettle, etc. Stings are 

 hollow and pointed, giving pain by an acrid liquor which they eject 

 when pressed. Scales are found on all parts of plants resembling the 

 scales of a fish ; on calyxes of compound flowers, on the envelops of 

 grasses and sustaining the stamens and fruit of the pine, oak, etc. 

 Tendrils are weak stems that clasp other bodies for support. They 

 commonly rise from branches, but rarely from leaf or flower-stalks. 

 They serve for roots in the ivy, trumpet flower, etc., and for shade in 

 the cucumber. They twine in pea-blossom plants ; and in the prefer- 

 ences and movements of tendrils generally, great apparent intelligence 

 is manifested. Pubescence is the downy, silky or woolly parts of plants. 

 With a magnifying glass they present interesting features and resem- 

 ble the clothing of animals. When in rows they are called fringes. 

 On mullein leaves they look like flannel or the felt of a white hat. 

 They assist evaporation and protect leaves from the cold. Dresses are 

 made of them in some places. They are of various forms. Bract 

 is a floral leaf situated near the flowers. In the sage they much 

 resemble the leaves, and they are often mistaken for the calyx. They 

 are green or colored, deciduous, or persistent. 



The Leaf. 



This is an expansion of the bark of the plant and consists of cellu- 

 lar substance, with ribs and veins running through it, the whole being 

 coveredby a green skin, or cuticle. The cellular tissue consists of 

 woody matter springing from the pith and liber. The tissue of the 



