BETULACEAE. — BETULA 483 



Betula humilisy var. Rtiprechtii Kegel in N'ouv. Mem. Soc. Nat. Mosc. XIII. 

 pt. 2, 109, t. 8, fig. 40-47 {Monog. Betulac. 51) (18G1) ; in Dc Candolle, Prodr. 

 XVI. pt. 2, 174 (1868). — Herder in Act. HorL Petrop. XII. 66 (1892). 



CHINA. Chili: Central and west Weichang, 1910, W. Purdom (No. 104). 



NORTHEASTERN ASIA. Transbaikalia: swamp near Sryetinsk, August 

 13, 1903, C. S. Sargent (fruits); "Dahuria" (ex Herb. Hort. Petrop.). Amur 

 and Ussuri : Amur, 1859, C. Maximowicz ; " am untem Amur: haufig auf nassen 

 Wiesen in der Niederung bei Kitsi," July 29, 1856, C. Maximowicz (type of var. 

 Ruprechiiana, ex Trautvetter) ; "am linken Schilka-Ufer gleich unterhalb der 

 Scheltuga-Mundung," May 19, R. Maack (type of B. palustris Gmelini, ex Maaok & 

 Ruprecht) ; " am mittleren Amur oberhalb der Garin-Mundung," July 25, R. Maack 

 (type of B. ovalifolia, ex Maack & Ruprecht); same place, R. Maack (type of B, 

 reticulata, ex Maack & Ruprecht) ; " Amur mcd.," May 27 and July 5, 1891, S. Kor- 

 shinsky; "am oberen Amur gleich unterhalb der Onon-Mtindung am linken 

 Amur-Ufer/' June 7, R, Maack (type of B. palustris, var., ex Maack & Ruyrecnt); 

 "Amursuperior," September 1, 1891, *S. Korshinsky (fruits). Korea: "fluvium 

 Tumingan, districtus Musang, vallis Pakapen," June 8, 1S97, V. Komarov (No. 

 488; young fruits); "in silvis pede montis Pai-ktu-san" (ex Nakai). 



I do not know where Pallas' type came from, and I am not sure whether all these 

 fonns mentioned in the synonymy above belong to the typical B. fruticosa Pallas. 

 It is probable that there are different forms and probably hybrids, too, mixed with 

 that species. Without having seen the type specimens of Pallas, Ruprecht, Traut- 

 vetter and Regel it is useless to try to distinguish any varieties. 



Sect. 4. EXCELSAEi W. D. Koch, Syn. Fl. Germ. Helo. ed. 2, 760 (1843). 



Bet2ila, sect. Alhae Regel inBidl Soc. Nat. Mosc. XXXVIIl. pt. 2, 396, incl. 

 Sect. Dahuricae (1865). — Prantl in Engler & Prantl, Nat. PJlanzenfam. 

 III. abt. 1, 45 (1SS7). — Koehne, Deutsche Dendr. 107 (1893). — Schneider, 



III. Handb. Laubholzk. 1. 109 (1904). 



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

 162 (1868), incl. subsect. Dahuricae. — Winkler in Engler, PJlanzenr. 1V.-61, 

 74 (1904), incl. B. fruticosa. — Ascherson & Graebner, Syn. Mitteleur. FL 



IV. 390 (1910). 



Subsect. a. Dahuricae Schneider, n. comb. 



Bdula, sect. Dahuricae Regel, in Bull. Soc. Nat. Mosc. XXXVIIL 396 (1865), 



excl. B. urticifolia. 



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



174 (1868), excl. B. urticifolia. — Schneider, III. Handb. Laubholzk. 1. 109 

 (1904). 



Betula, subgen. Dahunae [sic] Nakai in Tokyo Bot. Mag. XXIX. 40 (1915). 



Possibly there are American forms which might be referred to this subsection. 

 The whole classification of the difficult species and forms of a genus Uke Betula must 

 be a provisional one as long as we cannot refer to all the forms of the whole genus. 



25. Betula davurica Pallas, Rdse, III. 422, not., 321, 421, t. Kk, fig. 4 a-b 

 U'^6), fide Ledebour; Fl. Ross. I. pt. 1, 60, t. 39, tantum fig. A (1784). — Lede- 

 bour, FL Ross. III. pt, 2, 651 (1850). — Turczaninow in BulL Soc. Nat Mosc, 

 -P^VII. pt. 1, 401 (1854); FL Baical.-Dahur. II. 128 (1856). — Trautvetter, in 

 I^^ll. Soc. Nat Mosc. XXX, 445, t. 7 (1857). — Maximowicz m Mem. Sav. Btr, 



' Koch's name refers to the arborescent species B. alba Linnaeus and B. pubes- 

 cens Ehrhart in contrast to the "Humiles" and does not refer to B. excelsa Aiton. 



