182 On the Species of the Genus Primula in Essex. 
umbels and other monstrosities gradually disappear. 39 From 
an observation which I made in PeverilTs Wood on the 3rd of 
April, 1882, I conclude that this effect, which for convenience 
sake I have designated “stimulation” is very exhausting to 
the plants. The old flower-stalk becomes hard and dry, and 
remains standing until the following year ; and I noticed that 
those plants which had the most and the largest of these old 
stalks were then very small and stunted, often bearing only a 
few leaves with no flowers, from which I conclude that the 
cutting down of the wood at the beginning of the previous 
year had over-stimulated the plants to flower; and the con¬ 
sequence was that they were too exhausted to make any 
display this spring. There were, however, at the same time 
and place, many plants that were then in flower as profusely 
as any had been the year before, and I noticed that these 
had on them very few of the old flower-stalks ; I concluded that 
they were too young to flower the year before, as one-year-old 
Primula plants seldom produce flowers. This stimulation of 
the Oxlip is very curious and interesting, and I do not know of 
any plant which is affected in like manner to an equal extent. 
It seems to indicate that it was formerly a species liking the 
open, but which has now, for some reason, changed its habits. 
Before proceeding to describe the variations and monstrosi¬ 
ties produced in the Oxlip by stimulation, I wish to observe that 
I have never met with anything leading me to the belief that it 
is not a good and true species, perfectly distinct from both 
the Cowslip and the Primrose. With the exception of certain 
solitary flowers borne on single pedicels, the characteristics 
of the plant may be said to be almost constant , the flower 
varying only a trifle in size and in intensity of colour according 
39 As instances of this I may say that Pounce Wood was cut down in the 
winter of 1879-80. In the spring of the latter year I noticed scarcely 
any varieties there, but both in 1881 and 1882 I obtained many, though 
none in 1883. Great Hales Wood was, I think, cut in the beginning of 
1877 or 1878. What grew in 1879 I do not know, but in 1880 I got many 
monstrous umbels; in 1881 a very few, but in 1882 none, the bushes 
having then begun to grow up; part of Peverill’s Wood, Wimbish, was 
cut in the winter of 1880-81; in the spring of the latter year some 
varieties were obtained; in that of 1882, many. 
