202 On the Species of the Genus Primula in Essex.
very slight in the Oxlip, but I found two umbels out near
Walden on Nov. 18th, 1882, I have never heard of either
red or white flowers.
There are several slight, yet constant, characters by which
I believe this plant may invariably be distinguished from the
Hybrid Oxlip, and other forms and species; and I fully agree
with Mr. Darwin, who remarks ('Forms of Flowers,' p. 72)—
"In general appearance it differs so much from the Common
Oxlip (Hybrid) that no one accustomed to see both forms in
the living state could afterwards confound them; but there is
scarcely more than a single character by which they can be dis-
tinctly defined, namely, their linear oblong capsules, equalling
the calyx in length." This is certainly a good means of dis-
tinction, although it seems to have been omitted from 'English
Botany.' The capsules of the Cowslip and Primrose are, in
length, seldom more than 11/2 times their breadth; while in
the Oxlip they are often 3 or 31/2 times as long as they are
broad, and their tops project nearly one-third of their length
beyond the calyx.49 Nevertheless the shape of the capsules
varies a little, some being shorter and thicker, while others
are longer and narrower; but I have not been able to
connect these differences with the two forms. When com-
pared with the Hybrid Oxlip, the following differences are
most noticeable:—the peduncle is more slender, the calyx
fits far more tightly round the corolla-tube, the shape of the
umbel is far more graceful, the petals are widely funnel-
shaped, and not saucer-like; while they do not overlap at
their edges, as those of the other species often do. The petals
are of a pale buff-colour, totally distinct from the tint of the
other species. The character, however, which I believe to be
the most reliable one is the complete absence in the True Oxlip
but this was exceptional. Plenty, however, were open by the beginning
of March; by the 25th they were about in perfection. About the middle
of April they began to go off, and were over by the end of the month. In
1883 a very few came out at the beginning of March, but, cold weather
intervening, the majority did not appear till April, and they were over by
the end of the month.
49 See Ann. Nat. Hist., vol. ii. (1848), pp. 164—166; also Trans. Edinb.
Bot. Soc, iii. (1850), pp. 69—70.