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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"

The long-styled flowers greatly
preponderated on these eighteen plants,--61 consisting of this form, 15 of
equal-styled, and 9 of the short-styled form.
Primula vulgaris (var. acaulis, Linn.)
The primrose of English Writers.
(FIGURE 1.3. Outlines of pollen-grains of Primula vulgaris, distended with
water, much magnified and drawn under the camera lucida. The upper and smaller
grains from the long-styled form; the lower and larger grains from the short-
styled.)
Mr. J. Scott examined 100 plants growing near Edinburgh, and found 44 to be
long-styled, and 56 short-styled; and I took by chance 79 plants in Kent, of
which 39 were long-styled and 40 short-styled; so that the two lots together
consisted of 83 long-styled and 96 short-styled plants. In the long-styled form
the pistil is to that of the short-styled in length, from an average of five
measurements, as 100 to 51. The stigma in the long-styled form is conspicuously
more globose and much more papillose than in the short-styled, in which latter
it is depressed on the summit; it is equally broad in the two forms. In both it
stands nearly, but not exactly, on a level with the anthers of the opposite
form; for it was found, from an average of 15 measurements, that the distance
between the middle of the stigma and the middle of the anthers in the short-
styled form is to that in the long-styled as 100 to 93.


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