218 ZONES AND REGIONS [Pt. Ill, Sect. I 



The average daily increment during two months' observations was — 

 Culm No. I j in 58 days, 22-9 cm. per diem. 



„ „ 2, „ 60 ,, 19-0 „ „ 



„ „ 3. » 6o » J 9*9 » » 



The greatest increment in twenty-four hours was — 



Culm No. I, 57 cm. on 22nd December. 



„ „ 2, 42 „ „ 3rd January. 



„ ,, 3- 45 » n 4th „ 



Very quick-growing plants are not at all rare in the tropics, at any rate 

 in rainy districts. I have made some measurements, at the Buitenzorg 

 botanic garden, on young shoots and leaves of woody plants which 

 appeared to be growing very rapidly : — 



On the 15th November I measured a still folded leaf of Amherstia nobilis and 

 found, rachis 6 cm., a leaflet 2-9 cm. On the 24th Nov. the same rachis and leaflet 

 measured 31 cm. and 19-5 cm., showing an increased length of 5- and 7-fold respec- 

 tively in 9 days, or a daily increment of 4-1 cm. and i-8 cm. respectively. Of a some- 

 what older leaf of the same shoot the corresponding measurements on the 15th Nov. 

 were io-8 cm. and 3-5 cm., on the 24th Nov. 36 cm. and 197 cm. In Brownea sp., 

 the length of a bud just opening on the 15th Nov. was 8 cm. ; on the 20th Nov. the 

 young shoot, the leaves of which had not yet unrolled, was 18-5 cm. long ; on the 

 24th Nov. with the leaves opened quite flat, the measurement was 29 cm. to the extreme 

 leaf-tip. The total length had therefore increased more than 3^-fold in 9 days, in fact 

 by 21 cm., and this gives a daily increment of 2-6 cm. Other measurements of the 

 developing young shoots of Urostigma glabellum will be given subsequently in 

 connexion with the leaf-fall of trees. 



Haberlandt mentions several instances of rapid growth in Java : — 



'In 1874, at Willem Ill's school in Batavia, a plant of Eucalyptus alba, indigenous 

 in Timor, was planted ; after three years' growth it was already a tree, 15 meters in 

 height. In a plantation at Tjikomoh, near Buitenzorg, two-year-old mahogany plants 

 are 4^ meters high, and three-year-old plants of Swietenia macrophylla 5-6 meters 

 high. Albizzia moluccana— that admired shade-tree, the delicate pinnate foliage of 

 which does not give one any impression of abundant vigour and activity— grows with 

 fabulous rapidity. Fine yearling plants actually attain a height of 5-6 meters, six- 

 year-old plants are already 25 meters high, with stems measuring 20-25 centimeters 

 in diameter at the height of a man V 



In Honolulu Maxwell 2 undertook some investigations on the growth of 

 banana leaves. The averages of his results he tabulates as follows : — 



1 Haberlandt, op. cit., p. 115. 2 Maxwell, op. cit., p. 1. 



