164 On the Species of the Genus Primula in Essex.
thought it desirable to inquire further into the matter.
I have therefore taken considerable trouble to corroborate
and add to Mr. Darwin's somewhat brief remarks on this
subject, with results which will be best seen in the following
paragraphs. I have invariably counted my seeds, which, as
Mr. Darwin admits, is a vastly more correct method than
that which he himself, through want of time, adopted, namely,
weighing them. In most cases I have approximated any
remaining decimal to the nearest whole number. My first
observation was made on June 13th, 1882, when I procured
a number of capsules from wild Primroses, and, selecting six
of the finest of each, counted their seeds, though still green.
The results, which are given in Table V., show that the s.
produced more seed than the 1. in the proportion of 100 to 82.
On April 27th I marked 10 long-styled and 10 short-styled
Primrose plants growing together in a ditch at Chignal, and
gathered the unripe capsules at the end of June. The result
of counting their seed is given in Table VI. A considerable
number of the flowers had, as usual, produced no seed,
but whether these were mostly s. or mostly I. I kept, un-
fortunately, no account. The average fertility of all the
flowers of both forms which produced any seed is compared
in Table VII., from which the much greater fertility of the s.
may be seen.
It will be observed that the four highest numbers for the s.
are 79, 87, 87, and 89 ; and the four highest numbers for the
1. are 67, 71, 75, and 75, the highest of the latter being lower
by 4 than the lowest of the former ; also that the four lowest
numbers for the s. are 4, 5, 9, and 11; and the four lowest
numbers for the 1. are 9, 16, 17, and 18, the four latter num-
bers in this case being (with one exception) higher than the
four former numbers. It is noticeable that each long-styled
plant did not produce half so many umbels as the short-styled
ones—hence the greater fertility of the latter, as the number
of seeds per capsule was almost equal m both forms.
On June 29th, 1882, I obtained from near Saffron Walden
the umbels off 27 plants of Primula elatior (15 long- and 12
short-styled). Many of the plants had already burst some or