534 A NATURALIST IN THE PACIFIC 



NOTE 7 {page 15) 



Some Inland Hawaiian Plants possessing Buoyant Seeds or Fruits 



Three of these, Eclipta alba, Hibiscus Youngianus, and Hydrocotyle 

 verticillata, frequent wet places, and come under the principle that water- 

 side plants generally have buoyant seeds or fruits. The buoyancy of the 

 seeds of Argyreia tilirefolia and of Ipomea bona nox varies with station and 

 may be explained as under Ipomea in Note 5. The floating power of the 

 fruits of Colubrina oppositifolia may be akin to that of inland species of 

 Terminalia as indicated in Note 5, since another species of the genus 

 C. asiatica, which is a coast plant, has very buoyant seeds. Mucuna urens 

 was no doubt originally, as it now is in tropical America, a littoral plant. 

 The buoyant fruits of Pritchardia Gaudichaudii offer a genuine exception 

 to the principle (see page 330). 



NOTE 8 (pages 18, 112) 



The Pyrenes of Morinda 



The pyrenes of the two Malayan inland species of Morinda (M. umbel- 

 lata and M. longiflora) examined by Professor Schimper do not possess 

 the bladder-like cavity to which those of M. citrifolia owe their floating 

 power, and it is to be inferred from his remarks (p. 183) that they have 

 little or no buoyancy. The pyrenes of a Fijian inland species, near M. 

 Grayi, had no floating power as tested by me, and they lacked the bladder- 

 like cavity. 



NOTE 9 (page 18) 



The Buoyancy of the Fruits of Calophyllum 



Professor Schimper found that whilst the fruits of Calophyllum ino- 

 phyllum, the shore tree, remained afloat after 126 days, those of C. 

 amoenum, an inland species, sank in from three to fourteen days, both 

 possessing similar buoyant structures, but to a less degree in the case of i 



the inland species. This genus presents a parallel case to Terminalia 

 referred to on page 17 ; but the general discussion of the subject will be 1 



found in Chapter XIII. According to the above authority C. Calaba, a ! 



West Indian coast tree, has buoyant fruits. The same is also true of the 

 fruits of a large inland tree in the Solomon Islands experimented on by 

 me {Solomon Islands, p. 305). It would thus appear that the fruits of the 

 genus are as a rule buoyant, and that, as in Terminalia, the least buoyant 

 fruits belong to the inland species. Professor Schimper also shows 

 (p. 182) that the diminished floating power of the fruits of the inland f 



species is associated with diminution in thickness of the buoyant seed- ' 



shell which is most developed in the buoyant fruits of the strand species. 



