. A manual of botany. Botany. 20 MANUAL OF BOTANY Fig. 22. Forms of Boots.—The chief modifications of the forms of the root depend upon whether or no the primary root persists, and is always stronger than its branches; or whether it is but little developed and soon surpassed in vigour by the latter. In the former case we have the tap-root and its modifications, the chief of which are the conical, the fusiform, and the na^iform roots. Conical Boo^.—When a tap-root is broad at its base, and tapers towards the apex, it is termed conical. The roots of Monkshood (Aconitum Napellus), Parsnip {Pastin
. A manual of botany. Botany. 20 MANUAL OF BOTANY Fig. 22. Forms of Boots.—The chief modifications of the forms of the root depend upon whether or no the primary root persists, and is always stronger than its branches; or whether it is but little developed and soon surpassed in vigour by the latter. In the former case we have the tap-root and its modifications, the chief of which are the conical, the fusiform, and the na^iform roots. Conical Boo^.—When a tap-root is broad at its base, and tapers towards the apex, it is termed conical. The roots of Monkshood (Aconitum Napellus), Parsnip {Pastinaca sativa), and Carrot {Dauctis Carota) (fig. 25) are familiar examples of this form of root. Fusiform iJoot.—This term is applied to a tap-root which swells out a little below its base, and thence tapers upwards and down- wards {fig. 23). The common Radish, and Beet (Beta vulgaris), may be taken as ex- amples. Napiform Root.—This name is given to a root which is much swollen at its base, and tapers below into a long, point, the upper part being of a somewhat globular form (fig. 24). It occurs in a variety of the common Eadish (which is hence called the Turnip-radish), in the common Turnip, and in some other plants. In the cases where there is no permanent primary or tap-root we have other forms caused by modifications of the secondary roots. When a root divides at once into a number of slender branches or rootlets, or when the primary root is but little enlarged, and gives off from its sides a multitude of similar branches, it is called fibrous. Such roots occur frequently in annual plants, and may be well seen in annual Grasses (fig. 30), and in bulbous plants. Ti( bercular Boot.—When some of the divisions of a root become enlarged so as to form more or less rounded, oval, or ovoid expansions (fig. 26), the root is said to be tuherculated, or. Fig. 22. The Mangi-ove-tree {Rhizophora Mangle).. Please note that these images are extracted from scanned page images that
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