CHAP. civ. JSETULA'CE^:. SE'TULA. 1707 



tions that the leaves of B. nana vary exceedingly ; in the marshes of 

 Siberia, especially near Lake Baikal, and in Lapland and the arctic 

 regions, they are small, and not an inch in length ; but in Ingria, and 

 the alpine rocky situations of Dahuria, they are large, and frequently 

 broader than they are long. 



& 6. B. GLANDULo r SA Mtckx. The glandular-branched Birch. 



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

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



Spec. Char.,8fc. Branches beset with glandular dots, glabrous. Leaves obovate, serrate, quite entire 

 at the base, glabrous, almost sessile. Female catkins oblong; scales halfS-cleft. Seeds round, 

 with narrow margins. ( H'illd. 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 New- 

 Jersey and Pennsylvania ; flowering in May. (Pursk.) It seems to correspond, in America, with 

 the B. nana of Europe, and is probably only a variety of that species. It is not yet introduced. 



Leaves large. Natives of North America. 

 % 7. B. (A.) POPULIFO^LIA Ait. The Poplar-leaved Birch 



Identification. Ait. Hort. Kew., 3. p. 336. ; Willd. Sp. PI., 4. p. 463. ; Baum., p. 5.5. ; N. Du Ham., 



3. p. 204. ; Du Roi Harb. Baum., 1. p. 144. ; Marshal, p. 36. ; Pursh Fl. Amer. Sept., vol. 2. 



p. 620. ; Michx. N. Amer. Syl., vol. 2. p. 97. 

 Synonymes. B. acuminata Ehrh. Beit., 6. p. 98. ; B. lenta Du Roi Harb. Baum., ed. 1., p. 92., 



Wang. Beit., p. 45. ; white Birch and Oldtield Birch, Amer. 

 Engravings. Michx. Arb., 2. p. 139. t. 2. ; Willd. Baum., 1. 1. f. 5. ; Michx. N. Amer. Syl., vol. 2. 



t. 71. ; and our fig. 1560. 



Spec. Char., $c. Leaves deltoid, much acuminated, unequally serrated, quite 

 smooth. Scales of the strobiles having roundish side lobes. Petioles 

 glabrous. (Willd. Sp. PI., iv. p. 463.) A tree, in every respect closely 

 resembling B. alba, but growing with less vigour, and not attaining so large 

 a size as that species. A native of North America. 

 Varieties. 



B. (a.) p. 2 lacinidta, B. laciniata Lodd. Cat., ed. 1836, has large, 

 smooth, shining, deeply cut leaves, and appears to us to belong to 

 B. (a.) joopulifolia, rather than to B. alba. 



B. (a) p. 3 pendula, B. pendula Lodd. Cat., ed. 1836, has the spray 

 drooping, like that of the weeping variety of the common birch ; but 

 whether 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 from 

 30ft. to 40ft. high ; but, according to Michaux, 

 it only attains this height in favourable soils ^^ 



and situations. On trees that are fully grown, 



the branches are numerous, slender, and droop- iSf^^lM 1560 



ing. The leaves are smooth on both surfaces, -^^SVr^' 

 heart-shaped at the base, very acuminate, and ^^^fNM f ^S> 

 doubly and irregularly toothed. The petioles ^-^ w>?'' { -''"W 



are slightly twisted; and the leaves are thus ^ SHr 



rendered more tremulous than those of trees ^tt^BkJWr^ 

 on which this disposition is not observed. The -,- ... ., s s r .: Ltf^^H^ss* 

 buds, a few days after their developement, arc - LlFwP^SIj^ 



slightly coated with a yellowish odoriferous v^fe^J vat^MF^Sfc^ 

 substance, like those of B. alba. The trunk of 

 this species is clothed in a bark of as pure a 

 white as that of B. papyracea and B. alba ; 

 but its epidermis, when separated from the 

 cellular integument, is capable of being divided, 

 like that of B. nigra and B. excelsa, into thin 

 sheets, which constitutes an essential difference. 

 (Michx. N. Amer. Syl., ii. p. 98.) The tree 

 is indigenous to barren rocky woods and old 

 fields, from Canada to Pennsylvania. It is 

 rare in Virginia, and does not exist in the other southern states. It is 

 most frequently found in places scantily furnished with wood, where the 



