The natural history of plants, their forms, growth, reproduction, and distribution; . rd phyllotaxis. In the same way the three-eighthsarises from the one-third phyllotaxis if the consecutive dots are displaced -^ of thecircumference (15°) by the torsion, and the horizontal divergence no longer amountsto ^ of the circumference, but to f. The one-third becomes changed into theone-half phyllotaxis if the second leaf of a story, which in the bud was separated DISTRIBUTION OF THE GREEN LEAVES ON THE STEM. 407 from the first by ^ the circumference, in consequence of the torsion of the growingstem,
The natural history of plants, their forms, growth, reproduction, and distribution; . rd phyllotaxis. In the same way the three-eighthsarises from the one-third phyllotaxis if the consecutive dots are displaced -^ of thecircumference (15°) by the torsion, and the horizontal divergence no longer amountsto ^ of the circumference, but to f. The one-third becomes changed into theone-half phyllotaxis if the second leaf of a story, which in the bud was separated DISTRIBUTION OF THE GREEN LEAVES ON THE STEM. 407 from the first by ^ the circumference, in consequence of the torsion of the growingstem, is displaced about ^ the circumference (60°); that is to say, exactly so muclithat it is now separated from the first by half the circumference (180°). Thisparticular alteration can be very well seen in the developing branches of beeches,hornbeams, hazels, and many other trees and shrubs. In the buds the leaves havea one-third arrangement, in the fully formed, now woody branches the phyllotaxisappears to be one-half. Since, as a rule, amongst buds, the simplest cases, especialh. Fig. 102.—Displacement of the leaf-positions in consequence of torsion of the of the one-third into the two-fifths phyllotaxis. Dot 2 is displaced by torsion to 2; dot 3 to 3, &c. the one-third arrangement, are most frequently observed, it appears probable thatthe number of original phyllotaxes is really only very small, and that complicatedleaf arrangements, which are represented by fractions whose numerator consists oftwo figures, frequently are produced by torsion of the individual parts of the stemduring their growth. It still remains to point out here that the phyllotaxis becomesthe more complicated, the less the amount of torsion undergone by an internode, whichis, indeed, evident from the preceding representation. It is also worthy of note, thatin plants whose foliage-leaves originate 2, 8, or more together at the same height onthe stem (which therefore possess whorled le
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1902
