Chap. VI] ANIMALS 123 



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

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

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

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

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

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

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

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

 themselves to the flowers of one species. 



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

 species near Cape Town ; Promerops Gurneyi replaces P. caper in the eastern 

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

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

 London. 



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

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

 breast feathers of several species of these birds, also characterizes 

 several ornithophilous flowers. Labiates, species of Aloe, Irideae, and 

 Leguminosae assume this otherwise rare floral tint, when they are adapted 

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

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

 androecium and a protruding style. Similar features are observable also 

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

 of Couroupita. 



To ornithophilous flowers moreover belong many species of Protea, 

 whose large capitulate inflorescences are surrounded by rigid bracts at 

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

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

 (Fig. 62). Many of the Cape species of Erica are also adapted for 

 pollination by birds, as well as many Leguminosae, such as Erythrina 

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

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

 but not exclusively, ornithophilous. 



The most remarkable of the South African ornithophilous floral 

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

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

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

 as a large azure-blue arrow-shaped labellum, while the two others are 

 small and form an archway over the entrance to the nectar-cavity. 

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

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

 the edge of the labellum and sucks the nectar which is under the archway, 



