. Elements of botany. Plants. 46 ELEMENTS OF BOTANY. (2) Laying hold of objects by means of tendrils or twining branches or leaf-stalks, as shown in Figs. 30, 31. (3) Twining about any slender upright support, as shown in Fig. 32. 69. Tendril-Climbers.—The plants which climb by means of tendrils are very interesting subjects for study, but they cannot usually be managed very well in the schoolroom. Continued obser- vation soon shows that the tips of tendrils sweep slowly about in the air until they come in contact with some object about which they can coil them- selves. After the tendril has t
. Elements of botany. Plants. 46 ELEMENTS OF BOTANY. (2) Laying hold of objects by means of tendrils or twining branches or leaf-stalks, as shown in Figs. 30, 31. (3) Twining about any slender upright support, as shown in Fig. 32. 69. Tendril-Climbers.—The plants which climb by means of tendrils are very interesting subjects for study, but they cannot usually be managed very well in the schoolroom. Continued obser- vation soon shows that the tips of tendrils sweep slowly about in the air until they come in contact with some object about which they can coil them- selves. After the tendril has taken a few turns about its support, the free part of the tendril coils into a spii;al and thus draws the whole stem toward the point of attachment as shown in Fig. 30. Some tendrils are leaves or stipules, as shown in Fig. 90; others are modified stems. 70. Twiners. — Only a few of the upper internodes of the stem of a twiner are concerned in producing the movements of the tip of the stem. This is kept revolving in an elliptical or circular path until it encounters some roughish and not too stout object, about w^hich it then proceeds to coil itself. The direction of the coiling varies in different kinds of climbers, some following the course showm in the figure of the hop on the next page, others, as the morning-glory, taking the opposite course. 71. Underground Stems. — Stems which lie mainly or wholly underground are of frecxuent occurrence and of many Fig. 30. — Coiling of a Ten- dril of Bryony. a:,portion coiled around a twig; IV, to', places where direction of coiling reverses; m, un- coiled portion 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; Bergen, Joseph Y. (Joseph Young), 1851-1917. Bergen's Botany: key and flora, Pacific
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectplants, bookyear1896
