中文名（Chinese Name）：白桦
学名（Scientific Name）：Betula platyphylla Sukaczev
英文名（English Common Name）：Asian white birch
别名（Chinese Common Name）：粉桦、桦皮树
异名（Synonym）：Betula verrucosa var. platyphylla (Sukaczev) Lindl. ex Jansen；Betula alba subsp. mandshurica Regel；Betula alba subsp. tauschii Regel；Betula szechuanica (C. K. Schneid.) Jansen；Betula platyphylla var. mandshurica (Regel) H. Hara；Betula japonica var. mandshurica (Regel) H. J. P. Winkl.；Betula japonica var. rockii Rehder；Betula japonica var. szechuanica C. K. Schneid.；Betula platyphylla var. szechuanica (C. K. Schneid.) Rehder；Betula mandshurica (Regel) Nakai；Betula alba subsp. latifolia Regel
科属（Family & Genus）：桦木科（Betulaceae）桦木属
形态特征（Description）：乔木，高可达27米；树皮灰白色，成层剥裂；枝条暗灰色或暗褐色，无毛，具或疏或密 的树脂腺体或无；小枝暗灰色或褐色，无毛亦无树脂腺体，有时疏被毛和疏生树脂腺体。叶 厚纸质，三角状卵形，三角状菱形，三角形，少有菱状卵形和宽卵形，长3-9厘米，宽2- 7.5厘米，顶端锐尖、渐尖至尾状渐尖，基部截形，宽楔形或楔形，有时微心形或近圆形，边缘具重锯齿，有时具缺刻状重锯齿或单齿，上面于幼时疏被毛和腺点，成熟后无毛无腺点， 下面无毛，密生腺点，侧脉5-7(-8)对；叶柄细瘦，长1-2.5厘米，无毛。果序单生，圆 柱形或矩圆状圆柱形，通常下垂，长2-5厘米，直径6-14毫米；序梗细瘦，长1-2.5厘 米，密被短柔毛，成熟后近无毛，无或具或疏或密的树脂腺体；果苞长5-7毫米，背面密被 短柔毛至成熟时毛渐脱落，边缘具短纤毛，基部楔形或宽楔形，中裂片三角状卵形，顶端渐 尖或钝，侧裂片卵形或近圆形，直立、斜展至向下弯，如为直立或斜展时则较中裂片稍宽且 微短，如为横展至下弯时则长及宽均大于中裂片。小坚果狭矩圆形、矩圆形或卵形，长1.5 -3毫米，宽约1-1.5毫米，背面疏被短柔毛，膜质翅较果长1 /3，较少与之等长，与果等 宽或较果稍宽。
分布（Distribution）：产东北、华北、河南、陕西、宁夏、甘肃、青海、四川、云南及西藏，生于海拔400-4100米的山坡或林中。俄罗斯、朝鲜及日本也有。
用途（Use）：木材可供一般建筑及制作器、具之用，树皮可提桦油，白桦皮在民间常用以编制日用器 具。本种易栽培，可为庭园树种。
引自中国植物志英文版FOC Vol. 4 Page 310
Betula platyphylla Sukaczev, Trav. Mus. Bot. Acad. Imp. Sci. St.-Petersbourg. 8: 220. 1911.
白桦 bai hua | Betulaceae  | Betula
Betula alba Linnaeus subsp. latifolia Regel; B. alba subsp. mandshurica Regel; B. alba subsp. tauschii Regel; B. japonica Siebold ex H. Winkler; B. japonica var. mandshurica (Regel) H. Winkler; B. japonica var. rockii Rehder; B. japonica var. szechuanica C. K. Schneider; B. latifolia Komer; B. mandshurica (Regel) Nakai; B. platyphylla var. japonica Hara; B. platyphylla var. mandshurica (Regel) Hara; B. platyphylla var. szechuanica (C. K. Schneider) Rehder; B. szechuanica (C. K. Schneider) Jansen; B. verrucosa Ehrhart var. platyphylla (Sukaczev) Lindley ex Jansson.
Trees to 30 m tall; bark grayish white, exfoliating in sheets. Branches not pendulous, dark gray or dark brown, glabrous; branchlets brown, sparsely resinous glandular. Petiole slender, 1-2.5 cm; leaf blade triangular, ovate-triangular, rhombic-triangular, rhombic-ovate, or broadly ovate, 3-9 × 2-7.5 cm, abaxially densely resinous punctate, glabrous, bearded in axils of lateral veins, adaxially sparsely pubescent and resinous glandular when young, base truncate, broadly cuneate, or cuneate and subcordate, margin doubly or simply serrate, or incised-serrate, apex acute, acuminate, or caudate-acuminate; lateral veins 5-7(-9) on each side of midvein. Female inflorescence pendulous, oblong or oblong-cylindric, 2-5 × 0.6-1.4 cm; peduncle slender, 1-2.5 cm; bracts 5-7 mm, densely pubescent and ciliate, 3-lobed, middle lobe triangular-ovate, lateral lobes erect or spreading to recurved, ovate or suborbicular, slightly shorter to longer than middle lobe. Nutlet narrowly oblong, oblong, or ovate, 1.5-2 × 1-1.5 mm, sparsely pubescent, with membranous wings slightly longer than and about as wide as nutlet. Fl. Jun-Jul, fr. Jul-Sep. 2n = 28.
Temperate broad-leaved forests, shaded, S-facing slopes, ridges, dry, sunny slopes, marshes, forming vast, pure stands or mixed with Acer, Larix, Picea, Tilia, and other species of Betula; 700-4200 m. Gansu, Hebei, Heilongjiang, Henan, Jiangsu, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, SW and W Sichuan, SE Xizang, NW Yunnan [Japan, N Korea, E Mongolia, Russia (Far East, Siberia)]
This species has been divided into varieties or separate species (B. japonica, B. mandshurica, and B. szechuanica); however, the morphological characters are not distinct; therefore, the entities are all treated here as B. platyphylla. A. K. Skvortsov considers B. platyphylla to be synonymous with B. pendula.
A very important timber tree. The wood is soft and light, close grained, and fine to coarse textured; it is used for making agricultural tools, wooden ware, and tobacco boxes, and rarely for house construction. The white, papery bark is made into canoes and fancy articles, food baskets, and is also used as a substitute for tiles; the inner bark contains much resin.（责任编辑：徐晔春）