1923] WILSON, THE RHODODENDRONS OF NORTHEASTERN ASIA 35 



KEY TO THE SECTIONS 



Leaves persistent, glabrous or tomentosc beneath, never lepidote; ovary glabrous, 

 glandular or tomentose, never scaly; stamens 10 to 20; flowers several from a 

 terminal bud 1. Leiorhodium 



Leaves persistent, more or less clothed with lepidote glands; corolla rotate, cam- 

 panulate or funnel-form; stamens 10; ovary lepidote; flowers several from a 

 terminal bud v 2. Lepipherum 



Leaves persistent, more or less lepidote; corolla salver-shaped, with cylindric tube 

 and spreading limb, villose within the tube; stamens 5-10; ovary densely 

 lepidote, 5-celled; flowers several from a terminal bud 3. Pogonanthum 



Leaves usually deciduous, lepidote; corolla campanulate; stamens 10; flowers 

 solitary from lateral, clustered buds 4. Rhodorastrum 



Sect. 2. LEIORHODIUM Rehd. 



Rhododendron sect. Leiorhodium Rehder in Bailey, Stand. Cycl. Hort. 



v. 2937 (1916). 



Rhododendron sect. Eurhododendron Maximowicz in Mem. Acad. Sci. St. 

 Petersb. ser. 7, xvi. no. 9, 14 (Rhod. As. Or.) (1870), not Endlicher. 



KEY TO THE SPECIES 



Bud-scales deciduous; flowers pale- to rose-pink. Leaves covered with felt-like 



tomentum on the under side. 



Leaves narrowed at base; corolla 5- to 7-lobed 1. R. M etternichii . 



Leaves rounded or sub-auricled at base; corolla 5-lobed . . 2. R. brachycarpum. 

 Bud-scales persistent; flowers pale yellow. Leaves glabrous on the under side. 



3. R. chrysanthum. 



Rhododendron Metternichii Siebold & Zuccarini, Fl. Jap. i. 23, t. 9 (1835) ; 

 in Abh. Akad. Munch, iv. pt. 3, 6 (Fl. Jap. Fam. Nat. n. 130) (1846). 

 De Candolle, Prodr. vn. 721 (1839).— Maximowicz in Mem. Acad. Sci. 

 St. Petersb. ser. 7, xvi. no. 9, 21 (Rhod. As. Or.) (1870).— Franchet 

 & Savatier, Enum. PI. Jap. i. 287 (1875).— Mangles in Gard. Chron. ser. 2, 

 xvin. 85 (1882).— Nicholson, Diet. Gard. in. 296 (1887).— Shirasawa, 

 Icon. Ess. For. Jap. n. t. 60, figs. 1-13 (1908).— Bean, Trees & Shrubs 

 Brit. Isl. ii. 367 (1914). -Rehder in Bailey, Stand. Cycl. Hort. v. 2940 

 (1916).— Millais, Rhodod. 209 (1917). 



Rhododendron maximum Thunberg, Fl. Jap. 181 (1784), not Linnaeus. 

 Hymenanthes japonica Blume, Bijd. Fl. Ned. Ind. '862 (1826).— G. Don, 



Gen. Syst. in. 849 (1834). 

 Rhododendron Metternichii <*. heptamerum Maximowicz in Mem. Acad. Sci. 



St. Petersb., ser. 7, xvi. no. 9, 21 (Rhod. As. Or.) (1870). 



Rhododendron Hymenanthes Makino in Tokyo Bot. Mag. xvi. 33 (1902). 



Matsumura, Ind. PL Jap. u. pt. 2, 460 (1912). 

 Rhododendron Hymenanthes <*. heptamerum Makino in Tokyo Bot. Mag. xvi. 



33 (1902).— Matsumura, Ind. PI. Jap. u. pt. 2, 460 (1912). 

 Rhododendron japonicum Schneider, 111. Handb. Laubholzk. n. 490, figs. 323 



o-p, 324 b-c (1909), not Suringar. 



Shrub from 1-4 m. tall, branches stout, numerous. Leaves stoutly 

 petioled, oblong-lanceolate to oblanceolate, 5-12 cm. long, 1.5-4.5 cm. 

 wide, rounded, obtuse or short-cuspidate, base narrowed, rarely rounded, 

 dark lustrous green and glabrous above, densely clothed with floccose to 

 crustaceous gray to rufous-colored tomentum below\ Flowers pale to deep 



