MISCELLANEOUS PLANTS 



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it less able to withstand the injurious influence of the digestive 

 fluids of a bird for many hours. 



Though in appearance drupaceous, the fruit is described by 

 botanists as a nut wholly enclosed in the fleshy accrescent perianth. 

 When the fleshy covering has been removed, the nut is seen to con- 

 sist of a hard shell containing a kernel enclosing an embryo with 

 foliaceous cotyledons in a ruminate albumen. From the history of 

 such a structure alone, one would be inclined to doubt the imper- 

 meability of the seed-vessel. In this case the nut has a thin crustace- 

 ous shell with an outer membranous skin, the shell being wanting 

 at the lower end of the fruit, which seems to be a character of the 

 family. The gap in the shell is filled up with softer tissue almost 

 like a plug; and it is here that the place of weakness as regards 

 impermeability to fluids lies. 



Neither the entire fruit in its moist, fleshy coverings, nor the 

 freshly removed nut have any floating power; but after the fruit 

 has dried up on the ground it acquires buoyancy. It is in this con- 

 dition, with the withered outer coverings more or less removed by 

 insects and other agencies, that one finds these fruits under the trees, 

 the floating power being largely due to the fibro-membranous 

 covering investing the shell, and to its association with spongy cellular 

 tissue at the lower end. In Jamaica I made three experiments in 

 sea- water on the dried fruits gathered from under the trees in different 

 localities. In the first experiment half remained afloat after nine 

 days. In the two others 50 and 60 per cent, were floating after a fort- 

 night's immersion. The respective extreme limits of the floating 

 capacity in the three experiments were two weeks, four weeks, and 

 seven weeks. But water had always penetrated into the seed-cavity 

 of the sunken fruits, and as the fruits soon turned the sea-water 

 putrid, it had to be changed daily, results far from indicating any 

 special fitness of the fruits for prolonged transport by the currents. 

 On the whole I would infer that the penetration of sea-water would 

 in the course of a few days or weeks render these fruits quite un- 

 suited for effectual distribution over the ocean, and that although 

 they would float for a few weeks the germinative capacity would be 

 lost, as a rule, in a week or two. 



A practical inference from these results is that Coccoloba uvifera 

 could scarcely have reached the Bermudas with the aid of the currents. 

 The same objection on structural grounds must be raised to the view 

 that the fruits could withstand the influence of the digestive juices 

 of a bird during its passage across 800 miles of sea by the shortest 

 route to the Bermudas from the Bahamas. The view of the residents 

 that the tree has been introduced in later years is probably correct. 



From the foregoing remarks it would appear that a stretch of 

 from 100 to 200 miles of sea would be all that either the bird or the 

 current could accomplish in aiding the disposal of Coccoloba uvifera. 

 Yet the defects of the fruit that limit its capabilities for dispersal 

 are generic characters. It is, therefore, scarcely likely that any inland 

 species could be better adapted for distribution by birds, whilst in its 

 station alone it would lack opportunities for distribution by currents. 

 We could not go far wrong if we argued that in Coccoloba uvifera 



