POLLINATION OF THE BRITISH PRIMULAS. | 133 
Yet these long-tongued insects visit the flowers so comparatively seldom 
that it is difficult to believe that even they can pollinate adequately any of the 
three species. 
To obtain confirmation of this view, one has only to take one’s stand, on 
some day in early spring, in some cut-down wood, with Primroses or (in a 
certain district) Oxlips in flower all around one in such countless thousands 
that they make the ground appear covered with a vast carpet of pale yellow *, 
and then to watch. If the day be cold, wet, or windy (as are most days in 
early spring), one may wait for half-an-hour or longer without seeing even 
one single insect visiting the flowers. It, however, the day happens to be 
warm and bright, one may count on seeing quite a number of bees of several 
species, a good many bee-flies, and an occasional butterfly, all at work on the 
flowers. Yet, even so, one will observe almost invariably that the bees are 
engaged much more busily in visiting the few other flowers (Salix, Viola, 
Ranunculus Ficaria, Nepeta Glechoma, &e.) which are in flower at this early 
period, and that the crowd of bees buzzing round these forms a striking 
contrast to the few visiting the vastly-more-numerous Primula flowers. 
Or take the case of the Cowslip :— One may take one’s stand in a meadow, 
early in May, at the height of the plant’s flowering season, with hundreds of 
its blossoms in sight around ; yet, even on a fairly warm and sunny day, one 
may watch for, perhaps, ten or fifteen minutes before seeing even a single 
bee visiting a flower ; and, on a cold windy day, one is likely to see none at 
all. This species is visited by insects less often, I think, than either of the 
other two—perhaps because, when it flowers (which it does rather later than 
they), there are many other flowers of many species in bloom. 
It is clear, therefore, that the long-tongued insects belonging to Group 1, 
though they can (and, in fact, do) pollinate the flowers in the regular and 
orthodox manner, nevertheless visit them (as stated already) in small numbers 
and comparatively seldom—so seldom, in fact, that one is driven to the con- 
clusion that such sparse visitation cannot possibly suffice to effect, regularly 
and adequately, the pollination of any plants so immensely abundant and so 
extremely free-flowering as are all the three Primulas. 
I myself reached this conclusion many years since, and it has been reached 
independently by others who have studied the subject T. Thus, Mr. I. H. 
Burkill, after watching Primroses for many hours on the Yorkshire coast, 
* T have given elsewhere (see Trans. Essex Field Club, iii. p. 181 n.) figures which seem 
fully to support an estimate that,in favourable circumstances, a cut-down wood may pro- 
duce at least about 70,000 plants of P. elatior, bearing at least about 210,000 umbels, to an 
acre. In the case ef P. vulgaris, the number of plants and of flowers would probably be 
even larger. 
T An exception to this view is that of Mr. Scott Elliot, who says (see ante, p. 112) that, in 
Dumfriesshire, the visits of Bombus hortorum are “regular and sufficient” to pollinate the 
flowers— a conclusion which may be doubted in the absence of fuller details. 
