. Foundations of Botany. Botany. 74 FOUNDATIONS OF BOTANY (3) Twining abont any slender upright support, as shown in Fig. 42. 89. Tendril-Climbers. — The plants which climb by means of tendrils are important subjects for study, but they cannot usually be managed very well in the school- room. Continued observation 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 themselves. After the tendril has taken a few turns about its support, the free part of the tendril coils into a spiral and thus draws the whole st
. Foundations of Botany. Botany. 74 FOUNDATIONS OF BOTANY (3) Twining abont any slender upright support, as shown in Fig. 42. 89. Tendril-Climbers. — The plants which climb by means of tendrils are important subjects for study, but they cannot usually be managed very well in the school- room. Continued observation 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 themselves. After the tendril has taken a few turns about its support, the free part of the tendril coils into a spiral and thus draws the whole stem toward the point of attachment, as shown in Fig. 40. Some tendrils are modified leaves or stipules, as shown in Fig. 104 ; others are modified stems. 90. Twiners. — Only a few of the upper internodes of the stem of a twiner are concerned in pro- ducing 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 which it then proceeds to coil itself. The movements of the younger internodes of the stems of twiners are among the most extensive of all the move- ments made by plants. A hop-vine which has climbed to the top of its stake may sweep its tip continually around the circumference of a circle two feet in diameter, and the. Fig 40. - Coiling of a Tendril 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 & company
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