On the Species of the Genus Primula in Essex. 
157 
III. —The Relative Numbers of the Two Forms in Nature. 
Mr. Darwin lias stated 14 tliat “tlie two forms exist in a 
wild state in about equal numbers”; but, from my observa¬ 
tions, I shall, I think, be able to prove that this is not the 
case — there being a considerably larger number of long-stylecl 
plants than of short-styled ones. The above statement is 
made whilst treating of the Cowslip, but I presume that it 
may be taken to refer also to the other species of Primula . 
It is a little curious (although I regard it as a mere coin¬ 
cidence) that all the particulars on this point actually given 
by Darwin point to a conclusion differing from the results of 
my own observations; but as I have counted far more plants 
than he, and as this is a matter of fact and not of opinion, I 
venture to claim an ability to prove my case. For instance, 
he says of the Cowslip, 15 “ I collected 522 umbels from plants 
growing in several stations, taking a single umbel from each 
plant; and 241 were long-styled and 281 short-styled,” or as 
86 to 100. Of the Primrose he says, 16 “ Mr. Scott examined 
100 plants growing near Edinburgh, and found 44 to be long- 
styled and 56 short-styled; I took by chance 79 plants in 
Kent, of which 39 were long-styled and 40 short-styled; so 
that the tw T o lots together consisted of 83 long-styled and 96 
short-styled,” or as 86 to 100. He also quotes an authority 17 
who counted 29 hybrid Oxlips in Surrey, of which 13 were 
long-styled and 16 short-styled, or as 81 to 100. My own 
observations here follow in detail. My plan of operations 
was very simple : I merely gathered a single flower or a 
single umbel from each plant, and afterwards counted them. 
different heights; and I noticed more than one umbel on which there 
were both ordinary flowers and other flowers which were normal in every 
respect, except that the stigma was not raised more than one-eighth of an 
inch above the ovary. This great variability in the length of style seems 
to indicate that the plant is a little inclined towards heterostylism. 
[Muller also states (‘Die Befruchtung der Blurnen’) that P. longiflora is 
homostylic, and adapted by its long narrow corolla-tube for fertilization 
by Lepidoptera. The tube is 16 to 24 mm. long, and the nectar is, there¬ 
fore, accessible only to Jlacroglossa stellatarum (with proboscis 25 to 28 
mm. long), and to Deilephila euporbice (25 mm.) among all the Alpine 
Lepidoptera.— Ed.] 
14 ‘Forms of Flowers,’p. 18. 15 Ibid., p. 18. 16 Ibid., p. 34. 17 Ibid., p. 70. 
