The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . rvested seed from those flowersonly which protruded their stigma after this separationhad taken place and after the atavists had been weededout. Seed was harvested separately from each plant. Inthe following summer (1898, 8th generation) it wasseen that the seed of the best seed-parent had only pro-duced 45% atavists (among 100 plants that flowered).The seeds of the average seed-parents gave 56%, andthose of the worst, 59%. Selection had therefore a dis-tinct, although not a very great effect.
The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . rvested seed from those flowersonly which protruded their stigma after this separationhad taken place and after the atavists had been weededout. Seed was harvested separately from each plant. Inthe following summer (1898, 8th generation) it wasseen that the seed of the best seed-parent had only pro-duced 45% atavists (among 100 plants that flowered).The seeds of the average seed-parents gave 56%, andthose of the worst, 59%. Selection had therefore a dis-tinct, although not a very great effect. It should be re-marked that the number of average seed-parents was 8,and that of the worst ones 10. The composition of theprogeny was determined separately for each seed-parent, 152 Atavism. but the differences were not greater than the extent ofthe experiment would lead us to expect. There were1033 offspring from the average seed-parents and 732from the ten worst plants. The two separate cultureswhich deviated most from the mean contained 37% and65% atavists respectively. The value of 52% given. Fig. 27. Plantago lanceolata ramosa. A, B, C, three branched ears. above for the same generation but grown in 1900, willbe dealt with below. Bud-variations occur in this as in the inconstant racesof other species, although very rarely. In such cases itis one or several lateral rosettes which vary. The struc-ture of our plant is a very simple one. The stem of the Plaiitago Lanccolata Raniosa. 153 seedling grows out into a short, somewhat obhque. rhi-zom which produces a rosette of radical leaves. Earsare formed in the axils of the higher leaves but rosettesof the second order grow out from the axils of the lowerones. In the second summer the primary and secondaryrosettes behave in the same way, again producing earsabove and secondary rosettes below. If the plant growsvery rol^ustly it may consist of as many as 10-20 singlerosettes; if it is a ramosa every rosette produces branchedears,
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