Betula 981 



darker coloured horizontal lenticels, peeling off in transverse rolls ; on older trees 

 darkened and thickened at the base. Young branchlets, non-glandular, covered 

 with a dense, greyish tomentum ; older branchlets smooth, glabrous. Leaves 

 (Plate 269, Fig. 7) coriaceous, about 3J inches long and 2^ inches wide, oval or 

 ovate-oblong, rounded at the base, acuminate at the apex ; margin slightly ciliate, 

 irregularly serrate ; nerves nine to twelve pairs ; upper surface shining, dark green, 

 with scattered pubescence ; lower surface yellowish green, glandular, glabrous 

 between the nerves, which are slightly pubescent, and with dense axil -tufts of 

 pubescence ; petiole | inch, tomentose. 



Fruiting catkins (Plate 269, Fig. 7),^ cylindrical, i^ inch long, ^ inch in diameter, 

 on tomentose peduncles, variable in length ; scales with glabrous, ciliate, spatulate 

 lobes, the central lobe dilated above and obtuse at the apex, and often trifid, about 

 twice as long as the erect or slightly divergent lateral lobes ; nutlets with narrow 

 wings. 



Varieties 



In addition to the type, described above, which occurs in the Himalayas and 

 China, the following varieties can be recognised : — 



1. Var. sinensis, Franchet, Journ. de Bot. xiii, 207 (1899). 

 Betula albo-sinensis, Burkill, in /mm. Linn. Soc. {Bot.) xxvi. 497 (1899). 



Leaves glabrescent beneath. Fruit-scales glabrous, not ciliate ; nutlets smaller 

 than in the type. Discovered in north-eastern Szechwan by Pere Farges. Not yet 

 introduced. 



2. Var. Prattii, Burkill, Journ. Linn. Soc. {Bot.) xxvi. 499 (1899). Leaves 

 more pubescent than in the type, the pubescence extending over the whole under 

 surface, and very dense in the axils and along the midrib. Fruit-scales strongly 

 ciliate, with spatulate lobes, the lateral lobes spreading and not erect. This variety 

 occurs in western Szechwan, at high elevations (13,500 feet), and has not yet been 

 introduced. 



3. Var. Jacquemontii, Regel, in DC. Prod. xvi. 2, p. 177 (1868). 



Betula Jacquemontii, Spach, in Ann. Sc. Nat. sdr. 2, xv. 189 (i 841); Cambessedes, in Jacquemont, 

 Voyage dans I'Inde, Botanique, 157, t. 158 (1844); Regel, op. cit. 178 (1868). 



A tree, with white bark, marked by brownish horizontal lenticels, and peeling 

 off in transverse strips. Young branchlets slightly glandular, and covered with a 

 dense, erect, short pubescence. Leaves (Plate 270, Fig. 15), about 2\ inches long, 

 and if inch broad, ovate, rounded or slightly cuneate at the base, acuminate at the 

 apex, bi - serrate ; nerves seven to nine pairs ; upper surface with scattered 

 pubescence or glabrescent ; lower surface gland - dotted and glabrous except for 

 long hairs on the midrib and nerves; petiole f inch, glabrescent, glandular. 

 Fruiting catkins (Plate 270, Fig. 15), i\ inch long, \ inch wide, cylindrical, on 

 long pubescent stalks ; scales glabrous, ciliate, with an elongated linear central lobe, 



1 In this figure the middle lobe of the scale is represented short and trifid at the apex, as is occasionally the case ; but as 

 a rule it is more elongated, and broadened and rounded at the apex. 



