194 COLOURS OF FLOWERS AS A MEANS OF ATTRACTING ANIMALS. 



flowers, but blue flowers in the valleys of the Eastern Limestone Alps. The long- 

 spurred Violet (Viola calcarata) displays a blue corolla on the meadows of the 

 Western Central Alps, and a yellow corolla in the Eastern Alps of Krain. 

 Astragalus vesicarius has yellow blossoms in the Tyrolese Vintschgau, violet on 

 the Limestone Mountains of Hungary. Melittis Melissophyllum, in the Southern 

 Tyrol, has white flowers only; whilst in Lower Austria and Hungary it has 

 purplish-white flowers. The Alpine Poppy (Papaver alpinum) occurs on the debris- 

 slopes of the Lower Austrian and Styrian Limestone Alps with white flowers, in 

 those of the South-Eastern Limestone Alps, in Krain, with deep yellow flowers. 

 Anacamptis pyramidalis, on the north side of the Alps, is only seen with deep 

 carmine-red flowers; in the Dalmatian Islands and in Italy it exhibits pale flesh- 

 coloured blossoms. ATiemone alpina, on the Central Tyrolese Alps, bears chiefly 

 sulphur-yellow flowers; in the Eastern Limestone Alps its flowers are always white. 

 The crested Cow-wheat (Melampyrum cristatum) displays pale-yellow bracts on 

 its flower-spikes in the Southern Tyrol, but red ones in Lower Austria and 

 Hungary; indeed a long series of plants might still be mentioned which behave 

 in the same way, i.e. in which sometimes this sometimes that colour is the more 

 advantageous to the flower, and becomes the prevailing tint in diflerent regions 

 according to the presence of, and in combination with, other plants. 



In the descriptions of floral colour, so far given, green has always been 

 regarded as the one which formed the background or substratum from which 

 the other colours and colour-combinations must stand out if they are to be plainly 

 seen by flying animals. As a matter of fact, the ground-tone of the plant-covering 

 during the period of vegetation is mostly green; but in districts where the trees 

 and bushes strip ofi" their foliage in the autumn, and where throughout the winter 

 and spring a mantle of withered leaves covers the ground, the prevailing tint is 

 brown. Similarly, where in the autumn the grasses and various meadow- weeds also 

 wither and fade, the ground-tone of the plant-covered earth in the following spring 

 is not green but pale-yellow or brown. Against such a background obviously the 

 colour-contrasts become somewhat different. Blue colours show up better from a 

 brownish-yellow than from a green background, and it may depend upon this fact 

 that the flowers of so many plants which emerge in spring from the dry withered 

 leaves are coloured blue. The flowers of Hepatica triloba, growing in the depths of 

 light woods, are shown up excellently by their blue colour from the yellow-brown 

 Hazel and Hornbeam leafage, but would scarcely be noticed on a green meadow. 

 On ploughed land the flowers of Omplialodes verna can be seen 100 yards off" over 

 the pale yellow, faded grasses and foliage of the edge of the wood; while at the 

 same distance against a green background they would stand out much less clearly. 

 The same thing is true of many Boragineae, which grow in similar places (PulTnon- 

 aria angustifolia, offLcimalis, Stiriaca, Lithospermum purpureo-coeruleum), of the 

 Lesser Periwinkle (Vinca Tninor), of the Squill (Scilla bifolia), and of many others. 



Colour-contrasts which differ from those of the green background of land 

 covered with fresh foliage-leaves are also found in shady woodland spots where 



