70 THE NATURALIST IN NICARAGUA. [Ck. V. 



In vegetables, I grew three species of sweet potatoes 

 yellow, purple, and white skinned, and which differ also 

 in their leaves and flowers ; cabbages, kidney-beans, 

 pumpkins, yuccas (Jatropha manihot), quequisquea (a 

 species of arum, Colocasia esculenta), lettuces, tomatoes, 

 capsicums, endives, parsley, and carrots. 



The climate was too damp to grow onions ; neither 

 could I succeed with peas, potatoes, or turnips. Scarlet 

 runners (Phaseohis multiflorus) grew well, and flowered 

 abundantly, but never produced a single pod. Darwin 

 has shown that this flower is dependent, like many 

 others, for its fertilization upon the operations of the 

 busy hurnble-bee, and that it is provided with a wonder- 

 ful mechanism, by means of which its pollen is rubbed 

 into the head of the bee, and received on the stigma of 

 the next plant visited.-" There are many humble-bees, 

 of different species from ours, in tropical America ; but 

 none of them frequented the flowers of the scarlet runner, 

 and to that circumstance we may safely ascribe its' 

 sterility. An analogous case has been long known. 

 The vanilla plant (Vanilla plamfolia) has been intro- 

 duced from tropical America into India, but though it 

 grows well, and flowers, it never fruits without artificial 

 aid. It is the same in the hothouses of Europe. Dr. 

 Morren, of Liege, has shown that, if artificially fertilised, 

 every flower will produce fruit ; and ascribes its sterility 

 to the absence, in Europe and India, of some insect that 

 in America carries the pollen from one flower to another, f 

 When those interested in the acclimature of the natural 



* " Gardener's Chronicle," Oct. 2-1, 1857, and Nov. 14, 1858 ; also 

 T. H. Farren, in " Annals of Natural History," Oct. 1868. 

 f Taylor's " Annals of Natural History," vol. iii. p. 1. 



