156 CO-OPERATION AND THE ORIGIN OF FLOWERS. 
leaves were opposite. The vast majority of flowers do have 
three, five, or four sepals and petals. 
The Jurassic insect was in all probability a vegetable 
fiend. When the petals became red, all the more pollen-eaters 
and ovule-devourers would be attracted to it. 
What exactly is the effect of insect enemies to-day, 
especially upon foliage buds? In the Big Bud of currants, 
and in many other galls due to animals, there is a marked 
suppression of internodes.* Naturally, whatever sugar or 
other material is removed by the insect is no longer available 
for growth. According to M. Molliard, double flowers can 
be produced by infecting ordinary single flowers with eel- 
worms.; The same author has recently stated that Alyssum 
Densiflorum, described by Lange as a new species, is nothing 
but A. Maritimum suffering from severe attacks of an Aphis, 
and in consequence remarkable for short branches and a very 
condensed inflorescence. 
So the Jurassic insect’s visits would encourage a circular 
type of flower and also promote intense respiration, for this is 
a result of all injuries. It seems, then, that the original 
father and mother of all flowers, if it lived in strong sun- 
shine, in a windy place, and was attacked by insects, would 
first become coloured and then be induced to refrain from 
forming intervals between the insertions of the flower leaves. 
The same influences would tend towards the formation 
of such inflorescences as the spike and the head of Composite. 
Of 1259 species in the British flora, there are some 114 Com- 
posites and 383 other species, with one or other of these 
forms of display, that is over 4o per cent. of the total. 
We have here, then, an explanation of the origin of that 
variation which led to the true flower. It is a very simple 
one, and indeed obvious as soon as it is once pointed out, but 
that does not show that it is incorrect. 
It is hardly original, for Professor Henslow has men- 
* Here again is an opportunity for entomologists and botanists 
in this country (ninth series). 
t As to the relation between double flowers and mites or eel- 
worms, more experiments would be useful (tenth series). 
