628 



BOTANY OF THE LIVING PLANT 



Pollination. The flower is showy, and attracts also by honey secretion 

 outside the bases of the stamens. It is markedly protandrous. The five 

 outer stamens open first, followed by the five inner, but the stigmas remain 

 closely appressed together (in.), and expand only after the pollen is shed, when 

 the anthers curve away from them (iv.). This separation of the sexes both in 

 time and space makes self-pollination highly improbable, and the plant de- 

 pends upon cross-pollination resulting from insect visits. In other species 

 of Geranium, especially the smaller-flowered, self-pollination occurs, the separa- 

 tion of the sexes being less marked. On the other hand in the Scarlet 



Fig. 478. 

 Geranium pratense,L. I. whole flower. II. the same in section. III. the stamens 

 at time of dehiscence, the stigmas (stg) still closely appressed. IV. later stage with 

 stigmas {stg) recurved. V. gynoecium at same stage as IV. VI. ripe fruit dehisced. 

 VII. floral diagram. 



Geranium of gardens (Pelargonium) (22), the flowers are slightly zygomorphic, 

 and there is a deep honey-gland sunk in the pedicel opposite to the posterior 

 sepal, a specialisation still more perfected in the Nasturtium (Tropaeolum). 



ORDER: TRICOCCAE. 



Family : Euphorbiaceae. 



Example : The Caper- Spurge, or other 

 Species. 



The Euphorbiaceae, or Spurges, are a very large Family, of which the genus 

 Euphorbia is an extreme type. They have reduced, unisexual flowers, which 

 are sometimes isolated, with their floral envelopes developed, as in Phyllanthus ; 

 but in Euphorbia and others the flowers are closely grouped together, so that 

 a whole inflorescence may appear, and even functionate as a single flower. 

 The less reduced types indicate that their relation is with the Geraniales, from 

 which they may be regarded as an interesting reduction-series. 



(23) Euphorbia is represented in the British Flora by many species. They 

 are herbs or small shrubs with smooth surface, and milky juice. Their leaves 



