44 WRIGHT : THE GENUS DIOSPYROS 



Rate of Growth. 



The genus Diospyros, in Ceylon, possesses some of the 

 most slowly-growing tropical trees. In the seedling and 

 sapling stages, up to the first ten or twelve months the growth 

 takes place at a fairly rapid rate ; seedlings two months old 

 may measure, above ground, from 30 to 150 mm. according to 

 the length of the hypocotyl, but in two and a half years the 

 total height may exceed 3,300 mm. ; saplings ten years old 

 may measure less than this, and the subsequent growth takes 

 place at a slow rate. The following are the dimensions of 

 two and a half years old saplings raised in the same plot at 

 Peradeniya : 



a . Height. Circumference, 



mm. mm. 



D. montana 3,610 (11 ft. 10 in.) ... Ill 



D.Ebenmn ... 1,828 (6 ft.) ... 84 



D. Embryopteris ... 1,220 (4ft.) ... 81 



D. qusesita ... 610 (2ft.) ... 38 



Some species never develop into large trees, e.g., I), acute 

 and JD, prurjens. but the majority of Ceylon species attain 

 huge dimensions, particularly D. sylyatica, D. crumenata, and 

 D. affimg.. There are, however, very few trees of known age, 

 and exact information cannot therefore be obtained. There 

 is one specimen of J). quaesita in the gardens, which, though 

 known to be over sixty years old, measures only 472 mm. in 

 circumference and a total height of about 14 metres ; this, 

 however, is one of our slowest growing species ; other 

 species, notably D. Embryogteris and D. montana, probably 

 grow at a much quicker rate. 



Sample plots for observing the rate of growth have been 

 established by the Ceylon Forest Department, and yearly 

 observations have been made on selected trees in the various 

 forests ; the results are, however, at great variance. 



Broun states that after reaching a circumference of 914 mm . 

 (3 feet) D. Ebenum is very slow growing, and that the tree 

 may reach a circumference of 457 mm. (1 foot 6 inches) at the 

 age of 25 years, 914 mm. (3 feet) at 75 years, 1,372 mm. (4 



