300 



THE NATURE BOOK 



Another little plant which goes to 

 sleep in a very pretty fashion is the 

 Wood Son^el. The foliage of this Oxalis 

 is curioiislv responsi\"e to all sorts of 



^ ?*>" 



«»^,-,>;.*,., ,. 



DAISIES BY DAY AND NIGHT 



conditions ; so much so that it may 

 well be called the British Sensitive Plant. 

 Even to blow the foliage briskly is to 

 bring about a folding of the leaflets, 

 whilst a heavy cloud will induce the 

 gathering together of the foliage. Long 

 before the daylight has really fled, the 

 ])ale green lea\es are preparing them- 

 selves for the chill dews of night, whilst 

 the flower heads hang down in a vevy 

 disconsolate manner. 



Although it is a matter u]:)on which 

 we have not nun h dehnite knowledge, 



there is little doubt that these day and 

 night positions on the part of plants 

 are brought about by changes in the dis- 

 tribution of water in the cellular tissue. 

 In some way the waning light 

 induces an alteration in the 

 turgidity of the cells, with the 

 result that the tissue loses its 

 tenseness, and the leaf col- 

 lapses. 



It is not only in the plant 

 as a whole that striking changes 

 take place at the approach of 

 e\'ening. Quite as important 

 as the shielding of the foliage 

 from cold, is the protection of 

 the pollen from damage by the 

 lica\y dew deposits. To this 

 end some of the most beauti- 

 ful adjustments in the whole 

 floral world have been brought 

 into being, many of these really 

 mar\-ellous examples of Nature's 

 forethought. At noon the 

 meadow grass is starred all 

 o\er with Daisy flowers, but 

 some time before there is any 

 \'ery appreciable difference in 

 the degree of hght, the little 

 blossoms begin to close their 

 " slee})y red eyes." The pollen 

 produced by the central mass 

 of true flowers would be 

 serioush' injured by the falling 

 dews of evening did not the 

 encircling florets gather inwards 

 to shelter it from the moisture. 

 Perhaps even more striking is 

 the behaviour of the garden 

 Eschscholtzia, a well-known 

 ])lant hailing from California. 

 This species is a member of 

 the Poppy tribe, and has the 

 typical cup-shaped flowers, which under 

 the influence of the midday sun expand 

 to their fullest extent. So early does 

 the flower go to bed, however, that even 

 at midsummer the glowing orange and 

 yellow corolla will be folding itself up 

 by three o'clock, whilst an hour later 

 the whole flower will be com])letely closed. 

 It is rather curious to consider how it 

 is that the Eschscholtzia can be so 

 quickly influenced 1)\- the waning light 

 in thi- early afternoon, especially when 

 it is remembered tluit the flower opens 



