Primula vulgaris var. caulescens 237 
developed the caulescent form in a garden in one season only, there 
being no cowslips or oxlips anywhere near. 
Prof. J. W. Heslop Harrison, of Newcastle-on-Tyne, has favoured 
me with the facts of a case in which growth in an extremely-wet 
situation was, apparently, the actuating cause which led certain 
primrose plants to produce caulescent flowers. In the north of 
England, he says, he 
once found several plants with very-pronounced stalks growing in 
a waterfall. These, when removed to the garden, promptly reverted 
to the ordinary form and remain so now. I cannot [he adds] con¬ 
ceive of these plants being hybrids. The strange habitat and other 
points are against it. 
It is, I think, easy to understand that an excess of moisture might 
induce the primrose, a marked lover of moisture, to develop its 
latent peduncle; and the fact that the plants in question reverted 
to the normal (acaulescent) type of inflorescence when removed to 
a drier situation seems strongly to support this view. 
Further, there seems good reason to believe that this tendency of 
the primrose to produce caulescent (umbellate) flowers in cultivation 
is, for some reason, specially marked in the western parts of England 
andWales. Thus, Lady This tleton-Dyer writes 1 : “Nearly all the garden 
primroses have a tendency here to become polyanthus 2 . Even the 
blue primrose, which is from a plant divided up, has few single 
flowers now.” Again, in Pembrokeshire, where the red variety of 
the primrose abounds and is frequently dug up by cottagers for 
removal to their gardens, Mr J. E. Arnett, of Tenby, informs me he 
has been told that plants so removed “grow like a polyanthus in 
two or three years.” There is other evidence to the same effect. 
It is, in any case, in no way remarkable that the primrose should 
be very ready, under stimulation of any kind, to produce its flowers 
in umbels; for there can be no doubt that this is no more than a 
reversion to an ancestral form of inflorescence. The plant belongs to 
a large and widespread genus, comprising at least 250 described 
species, practically all of which bear their flowers in umbels. Indeed, 
it is easy to satisfy oneself that the flowers of the primrose, though 
apparently borne singly, are in reality borne in umbels ; for examina¬ 
tion of any plant when in full flower will show that the pedicels on 
which its flowers are borne all spring from one or more definite 
1 In a letter, dated May 15, 1922, to Mr Charles Nicholson. 
2 Here, clearly, the word is used adjectivally in its literal sense of many- 
flowered : not as the name of the particular many-flowered primula commonly 
known as "the polyanthus.” 
