XXII THE TREE-LOBELIAS 259 



capsules, opening by two pores ; whilst those of Apetahia are 

 seemingly dry and indehiscent. I do not imagine, therefore, that 

 the character of the fruit has determined to any important degree 

 the distribution of these plants. 



Nor is there reason to suppose that the fruits have acquired 

 their baccate character in Hawaii, and that they were originally 

 dry and capsular. Both types of fruit are found among the 

 arborescent Lobeliaceae of America, with which the Hawaiian 

 genera have their affinities. Centropogon, for instance, which 

 occurs in Central America and in the warm parts of North and 

 South America, has, according to Baillon, a somewhat fleshy berry. 

 It is noteworthy that a similar question is raised with respect to 

 Cyrtandra as to the relation between fleshy fruits in the Pacific 

 islands and dry or capsular fruits in the continental home of the 

 genus (see Chapter XXV.). 



The berries of the Tree-Lobelias would attract birds. We 

 learn from Mr. Perkins that one of the Hawaiian Drepanids, the 

 Ou, is very partial to the berries of some of the Tree-Lobelias 

 and especially those of Clermontia, the seeds passing unharmed 

 in the droppings. The mode of dispersal of the seeds of 

 the dry-capsular fruits is not so apparent ; but the fruits could 

 scarcely be less inviting to birds than the dry capsules of Metro- 

 sideros, the small seeds of which have in some way or other 

 been carried to almost every island-group of the Pacific. I have 

 beside me the dark brown, smooth crustaceous seeds of a species of 

 Clermontia. They measure ^V of an inch or o*6 of a millimetre, and 

 about 500 go to a grain. Mr. Wallace, in his book on Darwinism, 

 advocates the paramount influence of winds over birds for carrying 

 small seeds, like those of Orchis and Sagina, over tracts of ocean 

 a thousand miles across. I am, however, not inclined to think that, 

 except as regards the spores of cryptogams, winds have done 

 very much for Hawaii. For small seeds we can appeal not only to 

 the agency of birds and bats but also to insects (see Chapter 

 XXXHL). 



Observations of this kind, however, merely indicate that these 

 early Lobeliaceae possessed the same capacities for dispersal that 

 in the succeeding stages of the plant-stocking of the Pacific islands 

 have belonged to Metrosideros, Cyrtandra, Ophiorrhiza, Freycinetia, 

 and many other small-seeded genera. They go no way to explain 

 why the same agencies which transported the minute seeds in a 

 later age could not have been available for continuing the dispersal 

 of the early Lobeliaceae. To find an explanation we are compelled 



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