480 WILSON EXPEDITION TO CHINA 



(1911); in Tokyo Bot. Mag. XXIX. 44 (1915). — Schneider, III. Handb. Laub- 

 holzk. II. 488, fig. 553 1-m, 554 a-b (1912). 



Betula exalata S. Moore in Jour. Linn. Sac. XVII. 386, t. 16, fig. 8-10 (1879). 

 Belula chinensis, var. angusticarpa Winkler in Engler, Pflanzenr. IV.-61, 67, 

 fig. 19 K-L (1904). 



CHINA. Chili: Weichang, 1910, W. Purdom (No. 85; bush 1.8-3 m. tall; 

 flowers and old cones); Pohua-shan, near top of Mt. Conolly, alt. 1600-1800 

 m., July 1877, E. Bretschneider (type, ex Maximowicz). 



NORTHEASTERN ASIA. Mandshuria: Chien-shan, June 4, 1906, F. N. 

 Meyer (No. 90; fruits); same locality, alt. 300 m., F. Ross (No. 223, 428, 478, 553; 

 type of B. exalata, ex Moore and Burkill) ; prov. Mukden (ex Komarov). Korea : 

 " Districtus Mu-sang, Trajectus Czao-rieng, Fluvium Tumingan," May 23, 1897, 

 V. Komarov (flowers); "in montibus Nai-piang, supra 1000 m.," August 1901. 

 U. Faurie (No. 605; fruits); "in montibus Hoang-hai-to," August 1908, U. 

 Faurie (No. 203; fruits); "in monte des diamants," June 24, 1906, U. Faurie 

 (No. 204; young fruits). 



Forms of this species sometimes much resemble B. davurica Pallas, which, as 

 far as I have seen, has the young branchlets always more or less covered with 

 glands, but otherwise they are glabrous or sparsely pilose, not silky-villose, as in 

 B. chinensis. In the specimen distributed by U. Faurie under No. 204 the leaves 

 are very similar to those of B. davurica Pallas, but the middle lobe of the fruiting 

 bracts is as long as in typical B. chinensis and the pubescence of the young parts 

 is the same. See also under B. davurica Pallas. 



I do not know Betula collina Nakai (in Tokyo Bot. Mag. XXIX. 44 [1915]) 

 from northern Korea, " in Colle Ungil." According to the description it must be 

 very similar to B. chinensis Maximowicz. 



Sect. 3. HUMILES W. D. Koch, Syn. Fl. Germ. Helv. ed. 2, 761 (1843). — Prantl 

 in Engler & Prantl, Nat. Pflanzenfam. III. abt. 1, 45 (1887). — Koehne, Deutsche 

 Dendr. 107 (1893). — Schneider, III. Handb. Laubholzk. I. 103 (1904). 



Betula, sect. Nanae Kegel in Bull. Soc. Nat. Mosc. XXXVIII. pt. 2, 407 

 (1865). 

 To this section belong also different American species. Several of the forms 

 referred here need a careful investigation. 



Subsect. a. Nanae Schneider, n. comb. 

 Betula, sect. Eubetula, subsect. Nanae Kegel in De Candolle, Prodr. XVI. 

 pt. 2, 162 (pro parte) (1868). — Winkler in Engler, Pflanzenr. IV.-61, 

 69 (pro parte) (1904). 

 20. Betula nana Linnaeus, Spec. 983 (1753). — Kegel in Bull. Soc. Nat. Mosc. 

 XXXVIII. pt. 2, 407 (1865); De Candolle, Prodr. XVI. pt. 2, 171 (1868).— 

 Dippel, Handb. Laubholzk. II. 181 (1892). — Herder in Act. Hort. Petrop. XII. 60 

 (1892). — Koehne, Deutsche Dendr. 112 (1893). — Hempel & Wilhelm, Bdume & 

 Straucher, II. 26, fig. 132 E-H (1894). — Schneider, III. Handb. Laubholzk. I. 106, 

 fig. 55 f-i (1904). — Winkler in Engler, Pflanzenr. 1V.-61, 69, fig. 20 D-F (1904). — 

 Ascherson & Graebner, Syn. Mitteleur. Fl. IV. 406 (1911). — Marshall in Moss, 

 Cambridge Brit. Fl. II. 86, t. 88 (1914). 



Alnus nana Clairville, Man. d'Herb. 280 (1811). 

 Chamaebetida nana Opiz in Lotos Jahrb. Nat. V. 259 (1855). 

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

 101, t. 9, fig. 1-8, 13 {Monog. Betulac. 43) (1861). 



