CHAP. CIV.

jBetula'ceje. be'tula.

1707

tions that the leaves of B. nana vary exceedingly; in the marshes ofSiberia, especially near Lake Baikal, and in Lapland and the arcticregions, they are small, and not an inch in length ; but in Ingria, andthe alpine rocky situations of Dahuria, they are large, and frequentlybroader than they are long.

* 6. B. glandulo'sa Michx. The glandular-iranc/icrf Birch.

Identification. Michx. FI. Bor. Amer., 2. p. 180.; Willd. Sp. PL, 4. p. 466.; Pursh FI. Amer. Sept.,

2. p. 622.; N. Du Ham., 3. p. 208.

Spec. Char., Sjc. Branches beset with glandular dots, glabrous. Leaves obovate, serrate, quite entireat the base, glabrous, almost sessile. Female catkins oblong ; scales half 3-cleft. Seeds round,with narrow margins. {Willd. Sp. PI., iv. p. 466.) A handsome little shrub, not above 2 ft. high ;found in Canada, about Hudson’s Bay, and on the borders of lakes on the high mountains of NewJersey and Pennsylvania ; flowering in May. (Pursh.) It seems to correspond, in America, withthe B. ndna of Europe, and is probably only a variety of that species. It is not yet introduced.

Leaves large, Natives of North America.

I 7. B. (a.) populifo'lia Ait. The Poplar-leaved Birch

Identification. Ait. Hort. Kew., 3. p. 336. j Willd. Sp. PL, 4. p. 463.; Baum., p. 55. ; N. Du Ilam.,

3. p. 204. ; Du Roi Harb. Baum., 1. p. 144.; Marshal, p. 36. ; Pursh FI. Amer. Sept., vol. 2.p. 620.; Michx. N. Amer. Syl., vol. 2. p. 97.

Synonymcs. B. acumin&ta Ehrh. Beit., 6. p. 98.; B. lenta Du Roi Harb. Baum., ed. 1., p. 92.,Wang. Beit., p. 45.; white Birch and Oldfleld Birch, Amer.

Engravings. Michx. Arb., 2. p. 139. t. 2. ; Willd. Baum., 1.1. f. 5. j Michx. N. Amer. Syl., vol. 2.t. 71.; and our^g. 1560.

Spec. Char., Sfc. Leaves deltoid, much acuminated, unequally serrated, quitesmooth. Scales of the strobiles having roundish side lobes. Petiolesglabrous. (Willd. Sp. PL, iv. p. 463.) A tree, in every respect closelyresembling B. alba, but growing with less vigour, and not attaining so largea size as that species. A native of North America.

Varieties.

It B. (a.) p. 2 lacinidta, B. laciniata Lodd. Cat., ed. 1836, has large,smooth, shining, deeply cut leaves, and appears to us to belong toB. (a.) /jopulifblia, rather than to B. alba.

S B. (a) p. 3 pendula, B. pendula Lodd. Cat., ed. 1836, has the spraydrooping, like that of the weeping variety of the common birch; butwhether equally distinct or not, we have been unable to determine,from the very small size of the plants in the London collections.Description. The poplar-leaved birch, according to Pursh, is a tree from30 ft. to 40 ft. high ; but, according to Michaux,it only attains this height in favourable soilsand situations. On trees that are fully grown,the branches are numerous, slender, and droop-ing. The leaves are smooth on both surfaces,heart-shaped at the base, very acuminate, anddoubly and irregularly toothed. The petiolesare slightly twisted ; and the leaves are thusrendered more tremulous than those of treeson which this disposition is not observed. Thebuds, a few days after their developement, areslightly coated with a yellowish odoriferoussubstance, like those of B. alba. The trunk ofthis species is clothed in a bark of as pure awhite as that of B. papyracea and B. alba;but its epidermis, when separated from thecellular integument, is capable of being divided,like that of B. nigra and B. excelsa, into thinsheets, which constitutes an essential difference.

{Michx. N. Amer. Syl., ii. p. 98.) The treeis indigenous to barren rocky woods and oldfields, from Canada to Pennsylvania. It israre in Virginia, and does not exist in the other southern states. It ismost frequently found in places scantily furnished with wood, where the

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