Now, this is very much what we actually find to be the case in nature.  The simplest and earliest flowers are those with regular, symmetrical open cups, like the Ranunculus genus, the Potentillas, and the Alsine or chickweeds, which can be visited by any insects whatsoever; and these are in large part yellow or white.  A little higher are flowers like the Campions or Sileneoe, and the stocks (Matthiola), with more or less closed cups, whose honey can only be reached by more specialized insects; and these are oftener pink or reddish.  More profoundly modified are those irregular one-sided flowers, like the violets, peas, and orchids, which have assumed special shapes to accommodate bees and other specific honey-seekers; and these are often purple and not unfrequently blue.  Highly specialized in another way are the flowers like harebells (Campanulaceoe), scabious (Dipsaceoe), and heaths (Ericaceoe), whose petals have all coalesced into a tubular corolla; and these might almost be said to be usually purple or blue.  And finally, highest of all are the flowers like labiates (rosemary, Salvia, etc.) and speedwells (Veronica), whose tubular corolla has been turned to one side, thus combining the united petals with the irregular shape; and these are almost invariably purple or blue.

AMONG THE HEATHER

From ‘The Evolutionist at Large’

I suppose even that apocryphal person, the general reader, would be insulted at being told at this hour of the day that all bright-colored flowers are fertilized by the visits of insects, whose attentions they are specially designed to solicit.  Everybody has heard over and over again that roses, orchids, and columbines have acquired their honey to allure the friendly bee, their gaudy petals to advertise the honey, and their divers shapes to insure the proper fertilization by the correct type of insect.  But everybody does not know how specifically certain blossoms have laid themselves out for a particular species of fly, beetle, or tiny moth.  Here on the higher downs, for instance, most flowers are exceptionally large and brilliant; while all Alpine climbers must have noticed that the most gorgeous masses of bloom in Switzerland occur just below the snow-line.  The reason is, that such blossoms must be fertilized by butterflies alone.  Bees, their great rivals in honey-sucking, frequent only the lower meadows and slopes, where flowers are many and small:  they seldom venture far from the hive or the nest among the high peaks and chilly nooks where we find those great patches of blue gentian or purple anemone, which hang like monstrous breadths of tapestry upon the mountain sides.  This heather here, now fully opening in the warmer sun of the southern counties—­it is still but in the bud among the Scotch hills, I doubt not—­specially lays itself out for the humble-bee, and its masses