. The power of movement in plants . Plants; Botany. Chap. 1. TKOP^OLUM. 27 Fig. 16. vertically and coming into close contact. This upward move- ment differs from one of the great diurnal oscillations above described only by the position being permanent during the night and by its periodicity, as it always commences late in the evening. Tropseolum minus (?) (var. Tom Thumb) (TropaeolesB).—The cotyledons are hypogean, or never rise above the ground. By removing the soil a buried epicotyl or plumule was found, with its summit arched abruptly down- wards, like the arched hypocotyl of the cabbage p
. The power of movement in plants . Plants; Botany. Chap. 1. TKOP^OLUM. 27 Fig. 16. vertically and coming into close contact. This upward move- ment differs from one of the great diurnal oscillations above described only by the position being permanent during the night and by its periodicity, as it always commences late in the evening. Tropseolum minus (?) (var. Tom Thumb) (TropaeolesB).—The cotyledons are hypogean, or never rise above the ground. By removing the soil a buried epicotyl or plumule was found, with its summit arched abruptly down- wards, like the arched hypocotyl of the cabbage previously described. A glass filament with a bead at its end was affixed to the basal half or leg, just above the hypogean cotyledons, which were again almost surrounded by loose earth. The tracing (Fig. 16) shows the course of the bead during 11 h. After the last dot given in the figure, the bead moved to a great distance, and finally off the glass, in the direction indicated by the broken line. This great movement, due to increased growth, along the con- cave surface of the arch, was caused by the basal leg bending back- wards from the upper part, that is in a direction opposite to the depen- dent tip, in the same manner as occurred with the hypocotyl of the cabbage. Another buried and arched epicotyl was observed in the same manner, excepting that the two legs of the arch were tied together with fine silk for the sake of preventing the great movement just mentioned. It moved, however, in the evening in the same direction as before, but the line followed was not so straight. During the morning the tied arch moved in an irregularly circular, strongly zigzag course, and to a greater distance than in the previous case, as was shown in a tracing, magnified 18 times. The move- ments of a young plant bearing a few leaves and of a mature plant, win hereafter be Tropccolum minus (?): circum- Dutation of buried and arched epicotyl, traced on a horizon- tal glass, from 9
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Keywords: ., bookcentury1800, booksubjectbotany, booksubjectplants, bookyear18
