522 



XXVII. COMBRETACEAE 



The effects of light and shade and of soil-covering at the time the fruit 

 falls are indicated by the following results of experiments in six plots in the 

 same locaUty at Dehra Dmi : 



Termi7ialia tomentosa : survival and development of seedlings. 



Percentage of 



Condition of plot. 



(1) In full sunlight : on bare ground, 

 not weeded subsequently 



(2) In full sunlight : on short grass 



(3) In moderate side shade : on bare 

 ground, not weeded subsequently 



(4) In moderate side shade : on short 

 grass 



(5) In dense overhead shade : on bare 

 groimd, not weeded subsequently 



(6) In dense overhead shade : on short 

 grass 



germmation 

 (100 fruits 



scattered in 



each plot). 



42 



14 

 29 



45 



29 



Percentage and condition of survivors 



at end of first season. 

 40 ^ Seedlings up to 6 m. high ; plots 

 I covered wiih grass up to 1 ft. 

 12 J high. 



28 \ Seedlings health}-, up to 5| in. 



I high ; gromid moist with heavy 



4 I dew ; grass and weeds about 



J 9 in; high. 

 14 Of which only 2 health}-, 4 in. 

 high, on side of plot near light ; 

 remainder djdng. 

 6 Up to 5 in. high, only on side of 

 plot near light. 



The effect of light on natural reproduction has been further brought out 

 in two plots in close proximity to each other at Dehra Dun, one plot being 

 under the fairly heavy shade of bamboos and the other in the open. These 

 plots were laid out with the view of ascertaining if sal seed scattered on the 

 surface of a thick layer of leaves would germinate and the seedlings would 

 establish themselves under shade and in the open respectively. The leaves 

 in question were collected in the forest, and among them were a number of 

 fruits of Terminalia tomentosa. In the shaded plot several seedlings appeared 

 from these fruits during the rainy season in July and August : germination 

 was very successful owing to the wet layer of leaves. Of the seedlings which 

 appeared the survivals were only 4 in November, 2 in December, 1 in January, 

 1 in March, and none in July. It is probable that the mortality was due 

 not only to shade but also to want of moisture, since the ground became 

 decidedly dry after the rainy season was over ; this, however, would also 

 hold under similar conditions in the forest. In the open (unshaded) plot ten 

 seedlings appeared : although some of the fruits germinated on the dry upper 

 layer of the dead leaves a number failed to do so, and this indicates that 

 a thick layer of dead leaves in the open may prevent reproduction to some 

 extent, though to nothing like the extent wliich it does in the case of sal, 

 for the sal fruits fall after the season of leaf-shedding, whereas those of 

 Terminalia tomentosa fall in the early part of it and therefore do not he on 

 the top of the leaves. These ten seedlings all survived, and by October of 

 the second year varied from 1 ft. 5 in. to 4 ft. 2 in. in height ; some were 

 amongst grass about 2 ft. high and others were quite in the open. This experi- 

 ment clearly demonstrates the necessity for an abmidance of light for successful 

 natural reproduction. 



To summarize, it may be said that these preliminary experiments indicate 

 the foDowing to be some of the main factors which favour the estabhshment 

 of natural reproduction : (1) abundance of light, (2) a fair degree of soil 

 moisture. (3) bare ground. (4) loose soil, enabling the fruits to be slightly 



