On the Species of the Genus Primula in Essex. 155 
were equal-styled through deformity of the style. On one oc¬ 
casion, when over five per cent, of all the Primroses gathered 
were equal-styled, a very severe frost had occurred about a 
fortnight before, which probably had checked the development 
of the pistil. The stigmas were unusually small. It was 
noticeable that the stigmas of other flowers on those plants 
of P. elatior which bore any equal-styled flowers were variable 
in length. All the foregoing instances may, I think, be 
regarded as long-styled flowers with imperfectly developed 
styles; and as my first observation on the Cowslip, which 
gave 2-2 per cent, as equal-styled, was made as early in the 
year as March 29th, 1882, when very few were out, it is 
possible that some of these might ultimately have become 
normal. I have heard of cases, but never saw one, in which 
cultivated Primroses, properly short-styled, have become 
equal-styled from another cause, namely, imperfect develop¬ 
ment of the tube of the corolla. Thus it may be seen how 
constant this heterostylism is; neither Mr. Darwin nor 
myself, after an examination of an enormous number of wild 
Primula flowers, being conscious of ever having met with a 
truly equal-styled one. 12 Nevertheless the length of the style 
is variable to a certain extent, especially, I believe, in the 
flowers of the long-styled form, and even in the same umbel. 
Thus I have seen the stigma in three flowers on one umbel to 
project as much as one-fifth of an inch, which is not unusual, 
and often the stigma is as far within the tube. I have also 
not unfrequently seen the stigma of unopened buds projecting 
one-eighth of an inch beyond the tips of the teeth of the 
calyx. 
In the spring of 1882 the idea occurred to me to enquire 
how early in the development of the bud heterostylism exists. 
I therefore procured some very young buds of P. elatior and 
P. vulgaris , and, dividing them longitudinally, I found that 
in the very youngest, in which not a vestige of the petals 
appeared externally, the two forms were totally indistinguish¬ 
able unless it were by some microscopic difference. The 
anthers seemed to reach their full size and to become of a 
bright orange-colour long before the hud opened ; they were 
attached to the petals slightly above the ovary. The petals 
were quite rudimentary and almost devoid of colour, much 
12 If I may trust my memory, some specimens of P. farinosa which I 
gathered in the Alps were truly equal-styled, the stigma appearing with 
the anthers at the top of the tubes. If so, they were of singular interest, 
as I never met with such a case in any other species. Mr. Scott says 
(Proc. Linn. Soc. (1864), vol. viii., p. 115) that it is not uncommon for 
this species to be equal-styled. 
