BETULACEAE. — BETXJLA 485 



Regarding the variation in the shape of the fruiting bracts and the leaves we 

 might distinguish several forms. But such a thing could be done only after a 

 careful comparison of all the material preserved ia the herbarium of the Botanical 

 Garden at Petrograd. Among the specimens mentioned above there may be some 

 doubtful forms probably of hybrid origin. 



Beitila Rosac "Winkler 1 know only from the rather incomplete description; ac- 

 cording to this, Jack's specimen from Korea may represent this form. The leaves 

 and seeds are like those of B. davurica Pallas, and the shape of the bracts is the same 

 as that of other forms of this species; in this it resembles those of B.japonica Sie- 

 bold, the lateral lobes being very spreading and somewhat recurved. But the 

 middle lobe is always longer and narrower, and the lateral lobes are narrower, too, 

 than in B.japonica Siebold, which has the bracts generally finely pubescent on both 

 surfaces, while those of B. davurica Pallas are mostly only ciliate on the margins. 



In Japan I saw only one tree of this Birch. It grows near the village of Naka- 

 shinden at 1250 m. altitude, on the lower slopes of Yatsuga-dake, situated on 

 the borders of Kai and Shinano provinces. 1 was, however, told of other trees in 

 the neighl^orhood. The tree was about 15 m. tall with wide-spreading branches and 

 readily distinguished by its characteristic pale gray bark which splits and exposes 

 the many layers the free ends of which become rolled and form shaggy masses on 

 the tree. In habit and character of bark this species resembles the American River 

 Birch (S. nigra Linnaeus). E. H. W. 



Subsect. b. Albae Schneider, n. comb. 



Belula, sect. Albae Kegel in Bull. Soc. Nat. Mosc. XXXVIII. 396 (1865). 

 Betula, sect. Euhetula, subsect. Albae Kegel in De CandoUe, Prodr. XVI. pt. 2, 



162 (1868). 



Betula^ sect. Albae, subsect. Eualbae Schneider, IlL Handb. Laubholzk. I. Ill 



(1904). 

 Betula, sect, Eubetula, subsect. Albae, Gruppe Eualbae, Ascherson & Graeb- 



ner, Syn. Mitleleur. Fl. IV. 390 (1910). 

 Betula, subgen. Albae Nakai in Tokyo BoL Mag. XXIX. 40 (1915). 



26. Betula japonica Siebold apud Winkler in Engler, Pflanzenr. IV.-61, 78 

 (1904). — Nakai in Tokyo Bot. Mag. XXIX. 42 (1915). 



Betula japonica Siebold in Verh. Batav. Genoot. XII. 25 (Syn. PI. Oec. Jap.) 



(nomen nudum) (1830). — Siebold & Zuccarini in Abh. Akad. Munch. IV. 



pt. 3, 229 {FL Jap. Fam. Nat. I. 105) (nomen nudum) (1846). 

 Betula alba Turczaninow in Bull. Soc. Nat. Mosc. XXVII. 400 (non Linnaeus) 



(1854); Fl. Baical Dahur. II. pt. 1, 927 (1856). — Trautvetter & Meyer in 



MiddendorfT, Sibir. Reise, I. pt. 2, Bot. abt. 283 {Fl. OchoL) (1856).— 



Kuprecht in Bull. Pkys. Math. Acad. Sci, St. Petersbourg, XV. 381 (1857) ; in 



Mel. Biol. 11. 565 (1858). — Middendorff, Sibir. Rdse, IV. pt. 1, 565 



{Gewachse Sibir.) (pro parte) (1864). 

 Betula alba, var. t7jpica Trautvetter in Mem. Sav. Str. Acad. Sci. St. Petersbourg, 



iX. 249 (Maximowicz, Prim. Fl. Amur.) (1859). 

 Betula alba, var. vulgaris Kegel in Nouv. Mem. Soc. Nat, Mosc, XIII. 75 



{Monog. Betulac. 17), quoad syn. Trautvetteri (1861). — Shirai in Tokyo 



Bot. Mag. VIII. 319, t. 6, fig. 33-35 (1894). 

 Betula alba, var. verrucosa Kegel in Nouv, Mem. Soc. Nat. Mosc, XIII. 77 



{Monog, Betulac. 19) (1861), quoad specim. Kamtchat.—Franchet in Nouv. 



Arch. Mus. Paris, ser. 2, VIl. 91 {PI, David. I. 281) (1884). — Burkill in 



Jour. Linn, Soc. XXVI. 497 a899). 



