:HAr. VI] ANIMALS 123 



A role quite similar to that of humming-birds in the New World is 

 (layed by the Nectariniidae, or sun-birds, in the warm zone of the Old 

 Vorld, but only in tropical and Southern Africa do they appear in 



comparable number of species and individuals. The relations of sun- 

 lirds to flowers were investigated in South Africa by Scott-Elliot, whose 

 xcellent works have first opened out for us a closer insight into the 

 tructure of ornithophilous flowers. The South African sun-birds, accord- 

 ig to Scott-Elliot, are excellent pollinators, since they, like bees, confine 

 hemselves to the flowers of one species. 



Nectariiiia chalybea, N. bicollaris, and Promerops caper are the most important 

 pecics near Cape Town ; Promerops Gurnej'i replaces P. caper in the eastern 

 art of Cape Colony and in Natal ; Nectarinia famosa lives from December till 



pril in the Karroo, at other times in the districts of Knysna and East 

 ondon. 



Like humming-birds, the South African sun-birds also show a preference 

 )r red flowers, and indeed a certain red tint, which appears in the 

 reast feathers of several species of these birds, also characterizes 

 ;veral ornithophilous flowers. Labiates, species of Aloe, Irideae, and 

 .eguminosae assume this otherwise rare floral tint, when they are adapted 

 ) pollination by sun-birds. Characteristic features of the ornithophilous 

 owers of South Africa are also, in many cases, a brushlike polyandrous 

 adroeciimi and a protruding style. Similar features are observable also 

 humming-bird flowers, for example in those of Marcgraviaceae and 

 f Couroupita. 



To ornithophilous flowers moreover belong many species of Protea, 

 hose large capitulate inflorescences are surrounded by rigid bracts at 

 le base of which the honey accumulates ; the birds sit on the edge 

 f the cups and rub the protruding style that is covered with pollen 

 ^ig. 62). Many of the Cape species of Erica are also adapted for 

 Dllination by birds, as well as many Leguminosac, such as Erythrina 

 iffra, which possibly has no other visitors than sun-birds. The banana 

 1 Natal, and Ravenala madagascariensis in its native home, are mainly, 

 -It not exclusively, ornithophilous. 



The most remarkable of the South African ornithophilous floral 

 lechanisms occurs in Strelitzia reginae (Fig. 63), which is frequently 

 iltivated in our greenhouses. Its three external perianth-leaves are 



a bright orange colour ; of the three inner ones, one is differentiated 

 ; a large azure-blue arr»w-shaped labellum, while the two others are 

 nail and form an archway over the entrance to the nectar-cavity, 

 groove traced along the labellum encloses the stamens and the style, 

 le tip of which, with the stigma, projects freely. The bird hovers near 

 le edge of the labellum and sucks the nectar which is under the archway. 



