POLLINATION OF THE BRITISH PRIMULAS. 107 
(1) The Primrose (P. vulgaris Hudson, vel acaulis Linn.), 
(2) The Cowslip (P. veris Linn., vel officinalis Jacquin), 
(3) The True Oxlip (P. elatior Jacquin)*. 
On the distribution, distinctive features, and other peculiarities of these three 
species, as observable in Britain, I have already published two lengthy 
papers T. 
The question as to how the pollination of our Primulas is effected was first 
raised by Darwin. Between 1862 and 1868, he read before the Linnean 
Society five papers f, in which he pointed out clearly and conclusively the 
significance of heterostylism, especially as exemplified in the Primulas §. 
Later, these papers, collected and revised, appeared in the form of a work 
dealing comprehensively with the whole subject, as then known |. In the 
course of his investigations, Darwin naturally made observations to ascertain 
what insects effect the pollination of the Primrose and the Cowslip T ; and 
the results of these observations require notice at the outset. 
Of the Primrose, he wrote, in 1869 **, that it “is never visited (and I speak 
after many years’ observation) by the larger humble bees, and only rarely by 
smaller kinds: hence its fertilization depends almost exclusively on moths” — 
a statement the first portion of which is certainly incorrect, as Darwin him- 
self afterwards came to see. Much nearer the truth, though still somewhat 
short of it, is his final statement ff — ‘ 
lt is surprising how rarely insects can be seen during the day visiting the flowers, 
but I have occasionally observed small kinds of bees at work. I suppose, therefore, 
that they are commonly fertilised by nocturnal Lepidoptera. 
* As all three are very well known by their vulgar names, I use these in speaking of 
them hereafter. There are also two other British species of the genus—P. farinosa Linn. 
and P. scotica Hooker; but of these, though they are covered by my title, I have nothing to 
say. Nor have I anything to say of the various hybrids into which all three species enter, 
each with both the others: namely P. vulgaris x veris (the “ Common Oxlip”), P. vulgaris X 
elatior, and P, elatior x veris. 
t (1) Trans. Essex Field Club, iii. (1884), pp. 148-211, and (2) Journ. Linn. Soc., Bot. 
xxxiii. (1897), pp. 172-201. | 
t All afterwards published in its Journal (Bot.), vols. vi., vii., and x. 
§ “ Heterostylism” is the term he used, and it is preferable to, because more definite 
than, “heteromorphism,” a term suggested by Asa Gray and used by Lubbock and some 
later writers. 
| “The Different Forms of Flowers on Plants of the same Species’ (London, 8°, 1877). 
€ Darwin records no similar observations on the Oxlip, a plant he probably never saw 
growing wild. 
** See Journ. Linn. Soc., Bot. x. (1869), p. 438. 
tt ‘Forms of Flowers,’ p. 36 (1877). 
