1044 



THE NATURE BOOK 



Tliis plant has adopted strange means to 

 advertise the presence of its small labiate 

 flowers. When in bloom the terminal 

 leaves of each spike of this Salvia are 

 tinted in the brightest pink. There is no 

 doubt that these processes are true leaves, 

 seeing that when tra^•ersing the whole 

 of the stem it is possible to find leaves 

 which are half green and half pink. 



Further proof that the petals and sepals 

 of the flower have their origin in the 

 foliage of the plant is to be seen in the case 

 of those species in which the calyx or the 

 corolla persists after the blossom is 

 " over," and for a time practically per- 

 forms the offices of leaves. Thus with the 

 Christmas Rose the petal-like sepals which 



IN THE PiEONY THE LEAF OKIGIN OF THE CALYX IS 

 CLEARLY SEEN. 



go to make up what one may call the 

 corolla, are peculiarly tenacious in retain- 

 ing their position on the stem ; they do 

 not fade away after the maturity of the 

 essential organs, but lose their whiteness 

 and become green and leaf-hke in appear- 

 ance. Much the same process goes on in 

 the case of the Hydrangea, a plant wliich, 

 it is well known, surrounds its inconspicu- 

 ous flowers with showy bracts. These 

 bracts remain for a long time after the 

 flower has faded, finally becoming as green 

 as the leaves of the plant itself. Moreover, 

 there are certain species of plants in which 

 the coloured parts of the flowers graduaUy 

 develop from very green material. Tliis 

 is seen in the case of some of the Guelder 

 Roses {Viburnum), where the 

 undeveloped floral append- 

 ages practically perform the 

 offices of leaves during the 

 early stages of their exist- 

 ence. 



The conspicuous and often 

 attractively coloured sepals 

 and petals of the flower are, 

 after all, but of small im- 

 portance when compared 

 \\'ith the organs \\'liich go 

 to fill up the centre of the 

 typical bloom. We may, 

 perhaps, regard the calyx 

 and corolla in the light of 

 advertising agents whose 

 business it is to spread 

 abroad the knowledge of the 

 existence of the concern 

 which they envelop. As is 

 so well knowTi, the essential 

 organs of the plant consist 

 of the stamens and carpels, 

 these latter forming collec- 

 tively the pistil. It is the 

 duty of the stamens to pro- 

 duce the pollen grains, which, 

 coming into contact with the 

 ovules in the female portion 

 of the flower, bring about 

 the process of fertilisation. 

 If all goes well the outcome 

 of this union [is the seed — 

 the forerunner of the new 

 plant. 



It may not seem to be a 

 particularly easy matter at 

 first sight to determine what 



