. Elements of botany. Botany; Botany. ROOTS. 29 strength of the supplies of ready-made sap which it obtains from the host. 43. Forms of Roots. — The primary root is that wliich proceeds like a downward prolongation directly from the lower end of the caulicle. In many cases the mature root-system of the plant contains one main portion much larger than any of its branches. This is called a taproot, Fig. 16. Such a root, if much thickened and fleshy, would assume the form shown in the carrot, pars- nip, beet, turnip, salsify, or radish. Some plants produce multiple primary roots, a cluster procee
. Elements of botany. Botany; Botany. ROOTS. 29 strength of the supplies of ready-made sap which it obtains from the host. 43. Forms of Roots. — The primary root is that wliich proceeds like a downward prolongation directly from the lower end of the caulicle. In many cases the mature root-system of the plant contains one main portion much larger than any of its branches. This is called a taproot, Fig. 16. Such a root, if much thickened and fleshy, would assume the form shown in the carrot, pars- nip, beet, turnip, salsify, or radish. Some plants produce multiple primary roots, a cluster proceeding from the lower end of the caulicle at the outset. Roots of grasses, etci, are thread-like, and known as fibrous roots, Fig. 17. If such roots become thick- ened like those of the dahlia. Fig. 18, they are known as fascicled roots. These often closely re- semble tubers, but they may be distinguished from them. Fig. 15. — Dodder (a European species) Parasi- tic on tlie Willow. The plant is seen encircling a willow twig, into which it sends roots from the warty inner surface of its coils. b, scale-like leaves ; Bl, flower-cluster. At the left is shown the manner in which the parasite Cus encircles the host-plant W. The parasitic roots or haustoria H penetrate into tlie parenchyma of theharlc and into the fibro-vascular bundles, attaching them- selves to the various kinds of tissue, v, c, s, which they find in these. At the right are seedling dodder plants, the longest one growing at the tip from nourish- ment which it procures from the dying end next the root. by their mode of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bergen, Joseph Y. (Joseph Young), 1851-1917. Boston, Ginn
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1896
