45° A NATURALIST IN THE PACIFIC chap. 



always one-seeded, since two or even three seeds are occasionally- 

 produced, and they may all germinate. In November, 1897, 1 noted 

 eight hundred fruits of Rhizophora mangle germinating on the 

 trees in one of the creeks of the Rewa delta. Out of this number 

 eight fruits had two germinating seeds and one had three, the 

 protruding radicles being in all stages of growth. Just two years 

 afterwards I counted eight hundred more fruits in the same locality, 

 and then observed seven with two germinating seeds and none with 

 three, the radicles protruding in all cases. On another occasion at 

 Wailevu in Savu-Savu Bay I counted four hundred, and none had 

 more than a single radicle protruding. The results appear to vary 

 with the locality, but in the Rewa creek the proportion of fruits in 

 which more than one seed germinated was fairly constant at dates 

 two years apart, namely, about one per cent. Occasionally, how- 

 ever, in particular localities a greater proportion may be noticed. 

 Thus near Daku in the Rewa delta I found that the proportion was 

 between two and three per cent, for the same species (R. mangle), 

 those with three germinating seeds being about half per cent. 



The case of more than one seed germinating in the fruits of 

 Rhizophora mucronata never came under my observation ; but in 

 one locality, where I examined a considerable number of fruits 

 near the stage of germination, between ten and fifteen per cent, 

 showed two seeds approaching maturity. 



Warming thoroughly investigated the polyembryony of Rhizo- 

 phora more than twenty years ago, seemingly from materials 

 brought to him from the West Indies (Engler's Botanische Jahr- 

 buclur, band iv., 1883). With the usual German thoroughness he 

 deals with the work of earlier observers, and goes back to Piso in 

 the middle of the 17th century. Of the four ovules, he remarks, 

 three usually abort, and only in rare cases are two seeds developed. 

 He quotes Baron von Eggers to the effect that only in three per 

 thousand cases was more than one seedling observed protruding 

 from a germinating fruit. These remarks evidently all apply to the 

 American species. I do not find any reference in my notes to 

 polyembryony in Ecuador, and evidently its occurrence is not so 

 frequent there as in Fiji. 



It is frequently apparent in the cases where more than one seed 

 germinates in a fruit that on account of the difference in the length 

 of the protruding seedlings germination does not always begin at 

 the same time. Thus in Fiji the difference in the length varied 

 between one and three inches, an amount representing at least from 

 ten to twenty days' growth, as will be subsequently pointed out. 



