720 XLVI. VERBENACEAE 



was full of vigorous seedlings, but of the few seedlings which germinated in 

 the shaded plot none survived. The shade over the latter was removed on 

 June 28, 1915, and the admission of the sun's heat was at once followed by 

 the o-ermination of a number of seeds which had lain dormant for two years. 

 Numerous instances have been recorded in the forest of teak seedlings appearing 

 in quantity where the canopy has been opened ; some of these are quoted 

 below. Germination is greatly stimulated if the seed lies in the open 

 exposed to a thorough baking by the sun during the hot season, and to the 

 alternate soaldng and heating which it experiences during the early showers 

 preceding the monsoon proper. Germination then takes place chiefly at the 

 beginning of the monsoon, though in some cases it may continue throughout 

 the greater part of the rainy season. A case of failure of seed to germinate 

 when lying in an area shaded laterally is described below (p. 722). 



The beneficial effect of fire in stimulating the germination of teak seed 

 is now thoroughly realized in Burma. Experiments which I carried out in 

 that province in 1903 and 1904 showed that slight scorching, such as would 

 occur in a light leaf fire, stimulates germination, but that severe scorching, 

 amounting to charring of the fruits, destroys the vitality of the seed ; the 

 latter condition is produced by the firing of a thick layer of leaves or of 

 a somewhat heavy growth of grass. Under natural conditions the fruits fall 

 partly before and partly after the season of fires, and in burnt forests it is 

 probable that a portion of the seed-crop is destroyed by fire while a portion 

 has its germination stimulated by fire, the net result depending a good deal 

 on the nature of the soil-covering. In the case of seed lying dormant in the 

 ground, fire undoubtedly has a stimulating effect on germination, as various 

 experiments in Burma in cutting and burning the undergrowth have shown. 

 The measures now adopted in Burma for securing natural reproduction are 

 described in detail on p. 755 ; it will be seen that thorough burning is regarded 

 as essential to success. The beneficial action of fire is probably connected not 

 only with the heat produced by it, but also with its action in clearing and 

 aerating the ground. An experiment in Coorg ^ may here be referred to, in 

 which the undergrowth below twelve trees was burnt in the hot weather of 

 1908, with the result that a large number of natural seedlings sprang up, of 

 which only 184 survived the drip from the mother trees during the subsequent 

 monsoon. 



(ii) Soil-aeration. In the experiment referred to above, Mr. Hole demon- 

 strated that an admixture of dead teak leaves in fairly heavy loam was 

 beneficial to germination when the soil was kept well aerated and fully exposed 

 to light and air, but was injurious when kept constantly wet. In my experi- 

 ment at Tharrawaddy, described below, the beneficial effect of hoeing the soil 

 is clearly shown. Further experiments, however, are necessary to determine 

 the precise effects of soil-aeration under different conditions. 



(iii) Burying of the seed. Experiments at Dehra Dun, which were repeated 

 several times, showed that seed lying on the surface of the ground exposed 

 to the sun almost invariably fails to germinate owing to the fact that the 

 rafliole dries up or is eaten by insects or birds before it penetrates the soil ; 

 the drying up of the radicle is particularly liable to occur on hard ground. 



1 For. Admin. Report, Coorg, 1907-8. 



