CHAP. X 



MEANS OF CROSS-FERTILISATION. 



371 



many flowers were selected for experiment which pre- 

 sented some remarkable structure; and such flowers 

 often require insect-aid. Thus out of the forty-nine 

 genera in the first list, about thirty-two have flowers 

 which are asymmetrical or present some remarkable 

 peculiarity ; whilst in the second list, including species 

 which are fully or moderately fertile when insects were 

 excluded, only about twenty-one out of the forty-nine 

 are asymmetrical or present any remarkable peculiarity. 

 Means of cross-fertilisation. The most important of 

 all the means by which pollen is carried from the 

 anthers to the stigma of the same flower, or from flower 

 to flower, are insects, belonging to the orders of 

 Hymenoptera, Lepidoptera, and Diptera ; and in some 

 parts of the world, birds.* Next in importance, but 



* I will here give all the cases 

 known to me of birds fertilising 

 flowers. In South Brazil, hum- 

 ming - birds certainly fertilise 

 various plants which are sterile 

 without their aid: (Fritz Miiller, 

 4 Bot. Zeit.' 1870, pp. 274-5, and 

 4 Jen. Zeit. f. Naturwiss.' B. vii. 

 1872, 24.) Long-beaked hum- 

 ming-birds visit the flowers of 

 Brugmansia, whilst some of the 

 short-beaked species often pene- 

 trate its large corolla in order to 

 obtain the nectar in an illegitimate 

 manner, in the same manner as 

 do bees in all parts of the world. 

 It appears, indeed, that the beaks 

 of humming-birds are specially 

 adapted to the various kinds 

 of flowers which they visit: on 

 the Cordillera they suck the 

 Salviae, and lacerate the flowers 

 of the Tacsonise; in Nicaragua, 

 Mr. Belt saw them sucking the 

 flowers of Marcgravia and Ery- 

 thrina, and thus they carried 

 pollen from flower to flower. In 

 North America they are said to 

 frequent the flowers of Impatiens : 



(Gould, ' Introduction to the Tro- 

 chilida, 1 1861, pp. 15, 120 ; ' Gard. 

 Chronicle, 1 1869, p. 389; 'The 

 Naturalist in Nicaragua,' p. 129 ; 

 ' Journal of Linn. Soc. Bot.' vol. 

 xiii. 1872, p. 151.) I may add 

 that I often saw in Chile a Mimus 

 with its head yellow with pollen 

 from, as I believe, a Cassia. I 

 have been assured that at the 

 Cape of Good Hope, Strelitzia is 

 fertilised by the Nectarinidse. 

 There can hardly be a doubt that 

 many Australian flowers are fer- 

 tilised by the many honey-sucking 

 birds of that country. Mr. Wal- 

 lace remarks (Address to the Bio- 

 logical Section, Brit. Assoc. 1876) 

 that he has "often observed the 

 beaks and faces of the brush- 

 tongued lories of the Moluccas 

 covered with pollen." In New 

 Zealand many specimens of the 

 Anthorms melanura had their 

 heads coloured with pollen from 

 the flowers of an endemic species 

 of Fuchsia: (Potts, 'Transact 

 New Zealand Institute,' vol. iii. 

 1870, p. 72.) 



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