BETULACEAE. — BETULA 465 



Strobili sacpe nutantcs et subcj'lindrici; samararum alao nucula 

 aequilatae v. saepe latiores. Folia ut videtur satis l)r('vi(.cT ct 



anguste dentata 22. B. Middendorffti. 



ft Amenta fructifera pendula v. in 25. B. davurica subcrecta, cylindrica v. 

 subeliiptica. Folia saepe mediocra, majora plus quam 5 cm. longa (v. 

 pctioli 1 cm. longi v. longiores, v. amenta cylindrica et pendula), apicc 

 plus minusve acuminata v. subtriangularia, nervis utrincpie (4-)5-7 



(-8). Arbores Sect. 4. EXCELSAE. 



Folia ovata v. ovato-oblonga, basi cuneata v. cimeato-rotunda. Strobili 

 suberecti, elliptici v. subcylindrici; bractearum lobus medius saepis- 

 sime distinctus angustusque lateralibus subcrectis v. patentibus intcr- 

 dum paulo recurvis longior; samararum alae nucula 3^ angustiorcs v. 

 rarius subaequilatae. Cortex trunci junioris griseo-brunneus v. ex 

 parte flavus v. rubescens, lamellis laxis secedens. 



Subsect. a. Dahuricae. 



25. B. davurica. 

 Folia triangularia v. ovato- v. rhombico-triangularia. Strobili penduli v. 



subpenduli; bractearum lobi laterales fere semper margine superiore 

 recurvatis, satis latis, lobus medius brevis, basi dilatatus comparate 

 satis reductus; samararum alae nucula aequilatae v. usque duplo 

 latiores Subsect. b. Albae. 



26. B. japonica. 



ENUMERATIO BETULARUM ASIAE ORIENTALIS 

 NEC NON HIMALAYAE. 



Sect. 1. ACUMINATAE Regel in Bull. Soc. Nat. Mosc. XXXVIIl. pt. 2, 

 418 (1865). — Prantl in Engler & Prantl, Nat. Pflanzenfam. 111. Abt. 1, 45 

 (1887). —Schneider, III. Handb. Laubholzk. I. 97 (1904), II. 882 (1912). 



Beiulaster Spach in Ann. Set. Nat. ser. 2, XV. 198 (1841). 



Bctula, subg. Betulaster Endlicher, Gen. Suppl. IV. 20 (1847). 



Betula, sect. Betulaster Regel, subsect. Acuminatae Regel in De Candolle, 



Prodr. XVI. pt. 2, 179 (1864). — Winkler in Engler, Pjlanzenr. IV.-61, 88 



(1904). 



This section is well distinguished by the rather small and narrow bracts of the 

 fruiting catkins and by the broad winged seeds. The bracts of B. Maximowicziana 

 Regel only are somewhat like those of the other sections. The fruiting catkins are 

 racemose or solitary, narrow-cyUndric, long and pendulous. 



1 . Betula Maximowicziana Regel in De Candolle, Prodr. XVI. pt. 2, 180 (1868). — 

 Franchet & Savatier, Enum. PI. Jap. I. 456 (1875). — Shirai in Tokyo Bot. Mag. 

 VIII. 321, t. 6, fig. 36-38 (1894). — Sargent, Silva N. Am. IX. 48 (1896). — Shira- 

 sawa, Icon. Ess. For. Jap. I. 45, t. 23, fig. 1-8 (1900). — Mayr, Frcmdl. Wald- & 

 Parkbdume, 449, fig. 108 (1906). 



Bctula Maximomiczii Regel in Bull. Soc. Nat. Mosc. XXXVIII. pt. 2, 418, t. 6, 

 fig. 1-8 (non Ruprocht) (1865). — Rehder in Bailev, Cijcl. Am. Ilort. 1. 158 

 (1900). -Schneider, III. Handb. Laubholzk. I. 97, fig. 53 e, 54 c-c^ (1904); 

 II. 882 (1912). — Winkler in Engler, Pjlanzenr. IV.-61, 89, fig. 22 D-F 

 (1904). — Henry in Elwes & Henry, Trees Gr. Brit. & Irel. IV. 976, t. 269, 



