74 



INTRODUCTION 



inflorescence bears a number of pitcher-shaped nectaries, with their openings 

 turned towards the flowers. The fluid contained in these receptacles is sought 

 out by insects, which in their turn attract numerous insectivorous birds, many 

 species of humming-bird being among them. These touch with their backs the 



pendulous anthers, brush off the pollen, and 

 transfer it to the stigma when they visit 

 another flower (cf. Fig. lo). 



Another interesting example of the pol- 

 lination of flowers by birds, and one that 

 brings to mind the way in which Freycinetia 

 rewards the bats which transfer pollen, is 

 published by Fritz Muller (Kosmos, i, 1886, 

 pp. 93-8); — the flower of Feijoa, a tree 

 belonging to the family Myrtaceae, and 

 common in the Brazilian highlands, possesses 

 fifty to sixty very firm and stiff blood-red 

 stamens producing bright yellow pollen, and 

 a rigid dark-red style, which tapers above, 

 and bears a capitate stigma projecting beyond 

 the whorl of stamens. There is no nectary. 

 Above the four sepals, which are coloured red 

 on the inner side, there are four petals which 

 at first display their coloured outer surfaces. 

 They increase in diameter from 15 to 25 or 

 30 mm. Soon they roll up in such a way 

 that their coloured outer surfaces are covered, while the dazzling white inner surfaces 

 are visible from afar. These rolled petals are fleshy, and have a sweet taste, while 

 the young petals before rolling up are either tasteless or acrid. 



Fritz Muller states that the beautiful flowers of Feijoa are scarcely ever visited by 

 bees. On the other hand, according to the observations of Hans Lorenz (Fritz 

 Miiller's grandson, then five years old), the petals, which are rolled together like 

 omelettes, ready for a bite, are readily devoured by black and brown birds (probably 

 males and females of species of Thamnophilus), which in the process first of all 

 come into contact with and pollinate the prominent stigma, and then brush against 

 the pollen-covered anthers, thus covering themselves with a fresh supply of pollen. 



E. Ule has made a similar observation regarding a myrtle-like Brazilian shrub : 

 the petals, which taste like orange-sugar, are barely 5 mm. long, while the purple-red 

 stamens are almost 30 mm. in length. 



Fritz Muller has observed that humming-birds effect pollination in numerous 

 other Brazilian plants, such as species of Salvia, Rubiaceae, &c., and more especially 

 also in South Brazilian species of Abutilon. — ' A large and beautiful humming-bird, 

 the black breast of which shines like a glowing coal whenever the bird is in any way 

 excited,' writes Fritz Muller on August 26, 1871, to his brother Hermann, 'has, 

 with his inconspicuous wife, made himself almost completely master of the abutilons 

 in my garden, and drives away all other species. All flowers that are not under 

 cover are pollinated by him.' 



Fig. 10. Marcgravia nepentlwides^ Sec- 

 fttann, a Humming-bird flower. (After Witt- 

 mack.) A, Nectaries. 



