MONOECIA— POLYANDRIA. Betula. 153 



all botanists devoted to one object, as he was to fruits and seeds, 

 mostly attach too universal and exclusive importance to such 

 parts, in botanical discrimination, A good judge should con- 

 template the whole fructification and habit impartially, learning 

 from thence the limits of a genus, and not making technical 

 characters form the genus, as is now too often done ; witness 

 some able french writers on Orchidece, and a thousand unlearn- 

 ed ones on every side. Wiildenow cannot however pass un- 

 blamed for naming corolla in Castanea, what is evidently as 

 truly a calyx as in his Fagus. Could he really aim at making 

 only a more plausible generic character ? — Dr, Hooker very pro- 

 perly corrects him. 

 The nuts, termed Beech Mast, are the food of hogs, and of va- 

 rious small wild quadrupeds. By pressure they yield a sweet 

 oil, fit for many purposes, but which has, 1 know not why, dis- 

 appointed several speculators who aimed at making it a source 

 of pecuniary advantage. 



444. BETULA. Birch. 



Linn. Gen. 485. Juss.409. Fl.Br.lOW. Comp.ed.4. ]57. Tourn. 

 t. 360. Lam. t. 760. Gcertn. t. 90. 



Nat. Ord. see 7i. 4'4'2. 



Barr.Jl. Catkin cylindrical, lax, imbricated all round, with 

 ternate, concave scales ; the middle one largest, ovate. 

 Coi: none. Filam. 10 — 12, shoiler than the middle scale, 

 to which they are attached. Anth. roundish, 2-lobed. 



Fert. Jl. Ca^^m similar, but more dense; scales horizon- 

 tal, peltate, dilated outwards, 3-Iobed, 3-flowered. Cm: 

 none. Germ, compressed, bordered, of 2 cells. Styles 

 2, awl-shaped, downy. Stigm. simple. Nut oblong, de- 

 ciduous, winged at each side, of 1 cell, w^ith a solitary 

 kernel. 



Trees or sJinibs, very hardy, with round, slender branches; 

 scattered, stalked, simple, serrated, deciduous leaves ,• 

 and a hard, often veiny, 'wood. Bark, in several species, 

 of many fine, soft, membranous layers. 



1. B. alba. Common Birch. /3. Weeping Birch. 



Leaves ovate, acute, somewhat deltoid, unequally serrated, 

 nearly smooth. 



B.alba. Lmn, Sp. P/. 1393. Willd. v. 4. 462. Fl.Br. \012. Engl 



Bot. V.3]. t. 2198. Hook. Scot. 274. Fl. Dan. t. 1467. 

 B. n. 1628. Hall. Hist. V. 2. 299. 

 B. pubescens. Ehrh. Arh. 67. PL Off. 338. 



