The elements of botany for The elements of botany for beginners and for schools elementsofbotany00grayuoft Year: [1887] 36 ROOTS. [SECTION 5. Spindle-shaped, or Fusiform, when thickest in the middle and tapering to both ends; as the common Radish (Fig. 85). 76. These examples are of primary roots. It will be seen that turnips, carrots, and the like, are not pure root throughout ; for the caulicle, from tlie lower end of which the root grew, partakes of the thickening, perhaps also some joints of stem above : so the bud-bearing and growing top is stem. 77. A fine example of secondai7 roots (67
The elements of botany for The elements of botany for beginners and for schools elementsofbotany00grayuoft Year: [1887] 36 ROOTS. [SECTION 5. Spindle-shaped, or Fusiform, when thickest in the middle and tapering to both ends; as the common Radish (Fig. 85). 76. These examples are of primary roots. It will be seen that turnips, carrots, and the like, are not pure root throughout ; for the caulicle, from tlie lower end of which the root grew, partakes of the thickening, perhaps also some joints of stem above : so the bud-bearing and growing top is stem. 77. A fine example of secondai7 roots (67), some of which remaia fibrous for absorption, while a few thicken and store up food for the next season's growth, is furnished by the Sweet Potato (Fig. 86). As stated above, these are used for propagation by cuttings; for any part will produce ad- ventitious buds and shoots. The Dahlia produces fascicled (i. e. clustered) fusiform roots of the same kind, at the base of the stem (Fig. 87) : but these, like most roots, do uot produce adventitious buds. The buds by which Dalilias are propagated belong to the surviving base of the stem above. 78. Anomalous Roots, as they may be called, are tliose which subserve other uses tlian absorptiua, food-storing, and fixing the plant to the soil. Aerial Roots, i. e. those that strike from stems in the open air, are common in moist and warm climates, as in the Mangrove which reaches the coast of Florida, the Banyan, and, less strikingly, in some herbace- ous plants, sucli as Sugar Cane, and even in Indian Corn. Such roots reacli the ground at length, or tend to do so. Aerial Rootlets are abun- dantly produced by many climbing plants, such as the Ivy, Poison Ivy, Trumpet Creeper, etc., springing from the side of stems, wiiich they fasten to trunks of trees, walls, or other supports. These are used by the plant for climbing. 79. Epiphytes, or Air- Plants (Fig. SS), are called by the former name because commonly growing Fig. 88. Epiphytes
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