BETULACEAE. BETTJLA 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 comi)arison of all the material preserved in the herbarium of the Botanical 

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

 doubtful forms probably of hybrid origin. 



Bciula Rosae Winkler 1 know only from the rather incomplete descrijition; 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 tliis 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 i)ubescent on both 

 surfaces, while those of B. davurica Pallas are mostly only cihate 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 neighborhood. The tree was about 15 m. tall with wide-spreading branches and 

 readily distinguished by its characteristic pale gray bark which sjilits 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 {B. nigra Linnaeus). E. H. W. 



Subsect. b. Albae Schneider, n. comb. 



Betula, sect. Albae Regel in Bull. Soc. Nat. Mosc. XXXVIII. 396 (1865). 

 Betula, sect. Euhetula, subsect. Albae Regel in De Candolle, Prodr. XVI. pt. 2, 



162 (1868). 

 Betula, sect. Albae, subsect. Eualbae Schneider, III. Handb. Laubhohk. 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 Bot. Mag. XXIX. 40 (1915). 



26. Betula japonica Siebold apud Winkler in Engler, Pflanzenr. 1V.-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. Miinch. IV. 



pt. 3, 229 {FL Jap. Fayn. 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 & INIeyer in 



Middendorff, Sibir. Rcise, I. pt. 2, Bot. abt. 283 {Fl. Ochot.) (1856).— 



Ruprecht in Bull Phys. Math. Acad. Sci. St. Petersbourg, XV. 381 (1857) ; in 



Mel. Biol. II. 565 (1858). — Middendorff, Sibir. Rcise, IV. pt. 1, 565 



{Gewdchse Sibir.) (pro parte) (1804). 

 Betula alba, var. iypica Trautvetter in Mem. Sav. tltr. Acad. Sci. St. Petersbourg, 



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

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



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



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

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



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



Arch. Mus. Paris, s6r. 2, VII. 91 {PI. David. I. 2S1) (1884). — Burkill in 



Jour. Unn. Soc. XXVI. 497 (1899). 



