The Different Forms of Flowers on Plants of the Same Species — John Shaqi
The Different Forms of Flowers on Plants of the Same SpeciesDarwin, Charles
Science
The Different Forms of Flowers on Plants of the Same Species
Darwin, Charles
Fertilization of plants; Heterostylism; Plant physiology; Plants -- Variation; Pollination
According to Mr. Scott, the pistil of the long-styled form is fully four times
as long as that of the short-styled, but their stigmas are nearly alike in shape
and roughness. The stamens do not differ so much in relative length as the
pistils. The pollen-grains differ in a marked manner in the two forms; “those of
the long-styled plants are sharply triquetrous, smaller, and more transparent
than those of the short-styled, which are of a bluntly triangular form.” The
fertility of the two legitimate unions to that of the two illegitimate unions is
by the first standard as 100 to 95, and by the second standard as 100 to 31.
Primula cortusoides.
The pistil of the long-styled form is about thrice as long as that of the short-
styled, the stigma being double as long and covered with much longer papillae.
The pollen-grains of the short-styled form are, as usual, “larger, less
transparent, and more bluntly triangular than those from the long-styled
plants.” The fertility of the two legitimate unions to that of the two
illegitimate unions is by the first standard as 100 to 74, and by the second
standard as 100 to 66.
Primula involucrata.
The pistil of the long-styled form is about thrice as long as that of the short-
styled; the stigma of the former is globular and closely beset with papillae,
whilst that of the short-styled is smooth and depressed on the apex. The pollen-
grains of the two forms differ in size and transparency as before, but not in
shape. The fertility of the two legitimate to that of the two illegitimate
unions is by the first standard as 100 to 72; and by the second standard as 100
to 47.
Primula farinosa.
According to Mr. Scott, the pistil of the long-styled form is only about twice
as long as that of the short-styled. The stigmas of the two forms differ but
little in shape. The pollen-grains differ in the usual manner in size, but not
in form. The fertility of the two legitimate to that of the two illegitimate
unions is by the first standard as 100 to 71, and by the second standard as 100
to 44.]
SUMMARY ON THE FOREGOING HETEROSTYLED SPECIES OF PRIMULA.
TABLE 1.12. Summary on the Fertility of the two Legitimate Unions, compared with
that of the two Illegitimate Unions, in the genus Primula. The former taken at
100.
Column 1: Name of Species.
Column 2: Illegitimate Unions, Judged of by the Proportional Number of Flowers
which produced Capsules.
Column 3: Illegitimate Unions, Judged of by the Average Number (or Weight in
some cases) of Seeds per Capsule.
Primula veris : 69 : 65.
Primula elatior : 27 : 75 (Probably too high).
Primula vulgaris : 60 : 54 (Perhaps too low).
Primula Sinensis : 84 : 63.
Primula Sinensis (second trial) : ? : 53.
Primula Sinensis (after Hildebrand) : 100 : 42.
Primula auricula (Scott) : 80 : 15.
Primula Sikkimensis (Scott): 95 : 31.
Primula cortusoides (Scott): 74 : 66.
Primula involucrata (Scott): 72 : 48.
Primula farinosa (Scott): 71 : 44.
Average of the nine species : 88.4 : 61.8.
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