. The power of movement in plants. Plants; Botany. 506 MODIFIED OIRCUMNUTATION. Chap. X. In order to trace this upward movenient, a filament was iixed to a sub-peduncle bearing a capsule nearly ripe, which was beginning to bend upwards by the two means just described. Its course was traced (see C, Fig. 188) during 53 h., by which time it had become nearly upright. The course is seen to be strongly zigzag, together with some little loops. We may therefore con- clude that the movement consists of modified circumnutation. The several species of Oxalis probably profit in the following manner by th
. The power of movement in plants. Plants; Botany. 506 MODIFIED OIRCUMNUTATION. Chap. X. In order to trace this upward movenient, a filament was iixed to a sub-peduncle bearing a capsule nearly ripe, which was beginning to bend upwards by the two means just described. Its course was traced (see C, Fig. 188) during 53 h., by which time it had become nearly upright. The course is seen to be strongly zigzag, together with some little loops. We may therefore con- clude that the movement consists of modified circumnutation. The several species of Oxalis probably profit in the following manner by their sub-peduncles first bending downwards and then upwards. They are known to scatter their seeds by the burs'ing of the capsule; the walls of which are so extremely thin, like silver paper, that they would easily be penueated by rain. But as soon as the petals wither, the sepals rise up and enclose the young capsule, forming a perfect roof over it as soon as the sub-peduncle has bent itself downwards. By its subsequent upward movement, the capsule stands when ripe at a greater height above the groimd by twice the length of the sub-peduncle, than it did when dependent, and is thus able to scatter its seeds to a greater distance. The , which enclose the ovarium whilst it is young, present an additional adaptation by expanding widely when the seeds are ripe, so as not to interfere vrith their dispersal. In the case of Oialis aretosella, the capsules are said sometimes to bury themselves under loose leaves or moss on the ground, but this cannot occur with those of 0. carnosa, as the woody stem is too high. Oxalis acetosella.—The peduncles are furnished with a joint in Oxalia acetosella : conrse pursued by the upper part of a peduncle wliiLt rising, traced from U June 1st to 9 3rd. Figure here re- duced to one-half i)f the original scale. the middle, so that the lower part answers to the main peduncle. Please note that these images are extracted from s
Size: 1813px × 1378px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
