RUTACEAE 243 



2. The filaments make only one movement, which they execute simultaneously. 

 In the male stage they are erect, or else somewhat inclined towards one another, 

 so that the anthers touch ; in the female stage the stamens are curved outwards. 



(a) The anthers fall off when the filaments separate. As the stigmatic branches 



do not diverge till this stage, self-pollination is impossible. Ravenia. 



(b) The anthers persist after the filaments have separated. 



* In the male stage pollen may fall from the anthers upon the still sessile or 



immature stigma, and thus self-pollination may subsequently result. And 

 later on, owing to the wind or the position of the flowers, pollen from 

 the separate anthers may reach the mature stigma. 



(a) Zieria and Eriostemon. The style continues to grow in the second 

 stage of anthesis. 



(0) Boronia (ex parte). The stigma matures only at a late stage, 

 (y) Erytrochiton. The style elongates only at a late stage, but the stigma 

 comes into contact with the anthers before they have separated. 



* * Neither in the male nor in the female stage can pollen automatically reach 



the stigma from the anthers, owing to their position, and the adhesive 

 character of the pollen. Metrodorea. 



3. The filaments execute no movements either before or after the shedding 

 of the pollen. 



(a) Correa. Self-pollination of the pendulous flowers is ultimately possible after 



the stigmatic lobes have spread out, 



(b) Agathosma (ex parte). The style is enclosed by the staminodes in the 



male stage. In the female stage, the stigmas may still be pollinated, 

 should insect-visits fail, by pollen from the anthers of neighbouring flowers. 



B. Flowers homogamous. 



1. Automatic self-pollination is impossible — 



(a) in Boronia (ex parte), owing to the adhesive nature of the pollen ; 



(b) in Triphasia, because the stigma projects considerably beyond the anthers. 



2. Automatic self-pollination is impossible, owing to the position of the filaments, 

 but mutual automatic pollination of neighbouring flowers is favoured by the position 

 and torsion of the anthers. Agathosma (ex parte). 



3. Automatic self- and cross-pollination are not likely to occur ; self-pollination 

 by insect-visits is inevitable. Crowea. 



4. Automatic self-pollination is possible, but cross-pollination is favoured. 

 Cusparia, Choisya, Skimmia (ex parte), Mtuxaya, Citrus. 



II. Plants Diclinous. 



Self-pollination is impossible ; cross-pollination furthered. Ptelea, Skimmia 

 (ex parte). 



R 2 



