APPENDIX 595 



drupes would attract frugivorous birds and the pyrenes are well adapted for 

 this mode of dispersal. Mr. Perkins states that the drupes are much 

 sought after by the various species of Phaeornis, a genus of birds peculiar 

 to Hawaii. 



Deterioration oj Fruits for Purposes of Dispersal. — Among fruits oi 

 endemic genera that have evidently deteriorated in the Hawaiian Group as 

 far as fitness for dispersal is concerned, may be mentioned, in addition to 

 those of Phyllostegia and Stenogyne above noticed, those of the Araliaceous 

 genera, Pterotropia and Triplasandra, and the Amarantaceous Nototrichium. 

 The pyrenes of the first two genera on account of their thin covering, and the 

 seed of the last-named genus on account of its thin testa, seem ill-fitted now 

 for transport in a bird's stomach, yet we cannot doubt that their ancestors 

 originally arrived in this fashion. The same principle is also illustrated by 

 some Hawaiian non-endemic genera of later eras that possess peculiar 

 species, such, for instance, as in the case of Ekeocarpus discussed in 

 Chapter XXVI. 



NOTE 69 (page 366) 



On the Germination of Cuscuta 



My observations were made on the Hawaiian endemic species (C. 

 sandwichiana) and on a Fijian introduced species. Germination occurs 

 readily in fresh water, the floating seedling growing rapidly. When the 

 germinating seed is placed on wet soil in the shade, the seedling grows at 

 the rate of f inch (19 mm.) a day. The store of nutriment contained in 

 the swollen radicular end will support the seedling for a couple of days, 

 and if it has not then found a host it withers and dies. At first lying prone 

 the seedling then lifts its upper end into the air, and it was almost 

 pathetic to notice it moving round and round, endeavouring vainly to find 

 some object near. The seedlings make no effort to strike into the soil, 

 and when they are allowed to attach themselves to a plant they ascend 

 rapidly, growing at the upper end and dying at the lower end. 



NOTE 70 (pages 477, 480-1) 



On Beach-Temperature 



My data are rather scanty; but, judging from observations made in 

 Hawaii, in South America, and in the south of England, the following 

 scale would probably be true of typical beaches where the sand is found 

 relatively cool and moist at a depth of four or five inches. This moisture 

 seems to arise entirely from subsoil drainage seaward. When a beach 

 fronts an arid, rainless region, few if any plants grow on it ; the sand is 

 loose, hot, and dry at the depth indicated ; and the temperature of the 

 surface half-inch rises to between 130 and i4o°F., whilst four inches down 



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