Oct., i9!5.] a. KOIDZUML—THE VEGETATION OF J ALU IT ISLAND. 243 



been piled up. The ring of land encircling the lagoon is more 

 continuous on the north-east side, and its width varies from 

 few to 300 meters, often narrowing to the neck only few feet 

 across. On the three sides of north-east, south-west and south 

 east, the rhombic strip of land has an entrance into the harbour. 



The island lies in the moist tropical zone. The temperature 

 shows less variation, the mean maximum and minimum being 

 31°, 3 — 22°, 3 C. The annual mean temperature is about 27 c 

 C, and the mean monthly temperature ranges from 26 c , S C. 

 in July, to 27°, 8 C. in January. The north-east monsoon pre- 

 vails from December to April. From May to November, the 

 wind becomes unsteady, varying to the east and south-east. 

 The annual mean rainfall is very heav}', being 4500 mm. March, 

 May and December ai-e said to be the rainiest months. 



The whole of the main island is densely covered with vegeta- 

 tion, which may be divided as follows, into the three plant-for- 

 mations, each being subdivided into the several plant-associa- 

 tions. 



I. The coral-rock formation. 



1. Pemphidetum acidulae. 



2. Scaevola and Tournefortia association. 



3. Triumfettetum procumbentis. 

 II. The open sand-strand formation. 



4. Ipomoetum Pes-caprae. 



5. Crotalarietum longerostratae. 



6. Fimbristylidetum Wightianae. 



III. The Barringtonia formation. (Halophilous forest and 

 bushland ). 



a. Strandbushforest. 



7. Allophyletum timorensis. 



8. Wedelietum biflorae. 

 h. Strandforest. 



9. Cocos association. 



10. Leptuletum repentis. 



11. Thuaretum sarmentosae. 



12. Eragrostidetum ciliaris. 



13. Stenotaphretum americani. 



