428 



XXIII. LEGUMINOSAE 



up to five weeks had no harmful effect, a fact which is of importance in tracts 

 inundated for some time. 



Germination (Fig. 161, b-d). Epigeous. The radicle emerges and 

 descends. The hypocotyl elongates, arching very slightly or not at all, and 

 raises the cotyledons above ground ; as a rule the testa is carried up over 

 the cotyledons, falling with their expansion. 



The seedling {telia variety, Fig. 161). 



Boots : primary root long, thick in vigorous plants, otherwise thin and 

 wiry, terete, tapering, light brown : lateral roots numerous, short, fibrous : 

 small nodules present. Hypocotyl distinct from and thicker than young root, 

 0-7-1 -3 in. long, terete, cylindrical or tapering slightly upwards, expanded in 

 a ring at the base, pale green, glabrous. Cotyledons : petiole 0-1 in. long, thick, 

 glabrous : lamina 0-5 in. by 0-4 in., plano-convex, fleshy, less than 0-1 in. 

 thick, elliptical or ovate, apex rounded, base sagittate, entire, glabrous, pale 

 green beneath, darker above. Stem erect, somewhat zigzag at the nodes, wiry, 

 pale green, glabrous ; internodes variable in length, usually 0-2-0-4 in. long 

 in young seedlings. Leaves : first pair opposite or sub-opposite, subsequent leaves 

 alternate. Stipular spines in pairs at the base of the leaves at first 0-1 in. long, 

 increasing to 0-5 in. long after a few nodes. First pair of leaves paripinnate, 

 up to 1 in. long, with about four pairs of leaflets 0- 1-0-2 in. long, or second leaf 

 sometimes bicompound, subsequent leaves bicompound, first with one pair 

 then with two pairs of pinnae, the number of pinnae increasing subsequently. 



Under favourable conditions the development of the seedling is rapid 

 from the commencement, plants which germinate about July sometimes 

 reaching a height of 3 to 4 ft. by December, Experiments carried out at 

 Dehra Dun indicate that the chief factors stimulating rapid development are 

 an abundance of light and a loose soil free from weeds : irrigation also stimu- 

 lates growth, but in the seedling stages weeding and loosening of the soil are 

 even more important. The climate of Dehra Dun, it may be noted, is damper 

 than in any region where the tree grows naturally. The development is poor 

 on stiff clay. Experimental plots at Dehra Dun, some weeded and others 

 not weeded, some irrigated and others not, showed the following rate of 

 growth during the first season in respect of the three varieties of babul : 



Acacia arahica : growth of seedlings under different conditions, Dehra Dun. 



Irrigated. Unirrigated. 



Variety. Particulars. 



Telia Number of plants 



at end of season 

 Height 

 Condition . 



Kauria Number of plants 

 at end of season 

 Height 

 C'ondition . 



Ramkuli Number of plants 

 at end of season 

 Height 

 Condition . 



Weeded. 



Unweeded. 



Weeded. 



Unweeded 



99 15 28 12 



ft. 3 in. -2 ft. in. ft. 2| in.-l ft. in. ft. 9 in. -3 ft. 6 in. ft. 2 in.-l ft. 

 Chiefly vigoro us Weakly Chiefly vigorous Weakly 



36 80 38 2 



ft. H i--3 ft. 8 in. ft. 3 in. -2 ft. in. ft. 3 in.-3 ft. 6 in. Larger ft. 1 1 

 Chiefly vigorous Weakly Chiefly vigorous Weakly 



16 2 29 12 



Oft. 10 in. -4 ft. 3 in. Oft. 3in.-0ft. 5 in. Oft. 3in.-4ft. Oin. Oft. 2. V in. -Oft. 

 Vigorous Weakly Mgorous Weakly 



Approximately the same quantity of seed was sown in each plot, Init the 

 number of seeds sown was not recorded. 



