482 WILSON EXPEDITION TO CHINA 



Regel, 1. c, distinguish several varieties, and I believe there are also hybrids, 

 probably of different origin. Such forms, however, can only be correctly inter- 

 preted by comparing all the known material. 



23. Betula htimilis Schrank, Baier. Fl. I. 420 (1789), excl. cit. Gmelinii.^ — 

 Spach in Ann. Sci. Nat. ser. 2, XV. 193 (1S41). — Ledebour, Fl. Ross. III. pt. 2, 

 653 (1850). — Dippel, Handb. LauhholzJc. II. 180 (1892). — Koehne, Deutsche 

 Dendr. 112 (1893). — Hempel & Wilhelm, Bau?ne & Strducher, II. 26, fig. 122 A-D 

 (1S94).— Schneider, III. Hayidh. Laubholzk. 1. 103, fig. 55 b-e, 56 f-i, 57 c 

 (1904).-— Ascherson & Graebner, Syn. Mitieleur. Fl IV. 404 (1911). 



Betula fruticosa Ledebour, Fl. Alt. IV. 246 (1833), excl. syn, Pallasn et 



Gmelinii. 

 Betula humilis, var. genuina Kegel in Nouv. Mem. Soc. Nat. Mosc. XIII. pt. 2, 



106, t. 9, fig. 44-55 {Monog. Betulac. 48) (1861), excl. sjti. Pallasii; in De 



CandoUe, Prodr. XVI. pt. 2, 174 (1868). — Herder, in Act. Hort. Petrop. 



XII. 65 (1912). — Winkler in Engler, Pflanzenr. IV.-61, 74 (1904). 

 Betula kumiliSy var. commutata Hegel, in Nouv. Mem. Soc. Nat. Mosc. XIII. 



108, t. 10, fig. 4-14 (Monog. Betulac. 50) (1861). 



For further synonjTns and citations see Ascherson & Graebner, 1. c. 



The typical B. humilis Schrank does not occur, I believe, in eastern Asia, and 

 seems to reach the eastern limit of its range in the western Altai. The forms 

 of eastern Siberia, referred to B. humilis by different authors, may belong to B. 

 fruticosa Pallas and to B. glandulosaj var. sihirica Schneider. Probably also to other 

 forms not yet sufficiently understood, as B. Middendorjjii Trautvetter & Meyer. 



24. Betula fruticosa Pallas, Reise, III. App. 758, t. Kk, fig. 1-3 (1776); FZ. Ross, 

 I. pt. 1, 62, t. 40 A-C (m tab. eub B.fruticans) (1784). — Ledebour, FL Alt. IV. 

 246 (pro parte) (1833); Fl. Ross. III. pt. 2, 653 (1850).- K. Koch, Dendr. IL 

 pt. 1, 658 (1872), exclud. s>ti. Ledebourii. — Dippel, Handb. Laubholzk. II. 169 

 (1892). —Herder in Act. Hart. Petrop. XII. 59 (1892). — Koehne, Deutsche Dendr. 

 Ill (1893). — Komarov in Act. Hort. Petrop. XXII. 50 (Fl. Mansh. I1-) 

 (1903). — Schneider, III. Handb, Laubholzk. I. 103, fig. 56 d-e, 57 b~b^ (1904).— 

 Winkler in Engler, Pflanzenr. 1V.-61, 87 (1904). — Nakai in Jour. Coll. Sci. TokyOy 

 XXXL 203 {FL Kor, II.) (1911); in Tokyo BoL Mag. XXIX. 43 (1915). 



Betula, y humilior palustris Gmelin,^ FL Sibir. I. 167, t. 36, fig. 2 (1747). ^ 

 Betula Gmelini Bunge in Mem. Acad. Sav. Str. SL Petersbourg, II. 607 in 



observ. {Verz. Altai-Geb. Pfi. 85) (1835); Verz. Altai-Gcb. Pfi. ed. 8^ 113 



(1836). — Trautvetter, PL Imag. FL Ross. 10, t. 5 (1844). — Ledebour, FL 



Ross. III. pt. 2, 652 (1850). 

 Betula palustris Gmelini Ruprecht in Bull Acad. Sci. SL Petersbourg^ XV. 37b 



(1857); in MeL BioL II. 6, 558 (1858). 

 Betula palustris, var. Ruprecht, 1. c. 377 (1857); 1. c. 559 (1858). 

 Betula ovalifolia Ruprecht, 1. c. 378 (1857); 1. c. 560 (1858). 

 Betula reticulata Ruprecht, 1. c. 378 (1857); 1. c. 561 (1858), 

 Betula fruticosa, var. Ruprechtiana Trautvetter in Mem. Sav. Str. Acad.^<^' 



St Petersbourg, IX. 254 (Maximowicz, Prim. FL Amur.) (1859). — ^vn^- 



ler in Engler, Pflanzenr. IV.-61, 87 (1904). 



^ ScG under B, fTuiicosci Pullas 



« This Birch is cited by Schrank {Baier. FL I. 420 [1789]) under his B. humilis. 

 According to the figure it may be a form of B. fruticosa Pallas, who cites C^"^^*^^' 

 and it was named B. Gmelini by Bunge and Betula palustris Gmelini by RuprecM. 



