48 JOURNAL OF THE ARNOLD ARBORETUM (vol. iv. 



in either of these regions. It was discovered by early Russian travellers 

 in Siberia, probably by Messersch nidt or Steller, and is mentioned by 

 Gmelin (Fl. Sib. IV. 125, t. 55 [1769]) as "Azalea fol. ovalibus supra ru- 

 gosis" and is figured but the figure is crude. 



Sect. 4. RHODORASTRUM Maxim. 



Rhododendron sect. Rhodorastrum Maximowicz in M£m. Acad. Sci. 

 St. Petersb. s£r. 7, xvi. no. 9, 15 (Rhod. As. Or.) (1870). 



Represented by 8. R. dauricum 



Rhododendron dauricum Linnaeus, Spec. 392 (1753). — Pallas, Fl. Ross. 

 i. 47, t. 32 (1784).— Andrews, Bot. Rep. i. t. 4 (1799).— Sims in Bot. Mag. 

 xvn. t. 636 (1803).— Loddiges, Bot. Cab. vn. t. 605 (1822); xv. t. 1446 

 (1828).— G. Don, Gen. Syst. m. 845 (1834).— Loudon, Arb. Brit. n. 1138, 

 fig. 939 (1838).— DeCandolle, Prodr. vn. 725 (1839).— S. O. in Loudon, 

 Gard. Mag. n. ser. vn. 462 (1841).— Ledebour, Fl. Ross. n. 921 (1846).— 

 Turczaninow in Bull. Soc. Nat. Mosc. xxi. no. 7, pt. 2, 501 (Fl. Baical. 

 Dahur.) (1848). — Maximowicz in Mem. Acad. Sci. Sav. Etr. St. Petersb. 

 ix. 189 (Prim. Fl. Amur.) (1859); in Mem. Acad. Sci. St. Petersb. ser. 7, 

 xvi. no. 9, 43 (Rhod. As. Or.) (1870).— Trautvetter & Meyer in Midden- 

 dorff, Reis. Sib. i. pt. 2, 63 (Fl. Ochot.) (1856).— Regel in M&n. Acad. 

 Sci. St. Petersb. s6r. 7, iv. no. 4, 102 (Tent. Fl. Ussur.) (1861). -P. A. in 

 Gartenwelt, vn. 413, fig. (1903). — Komarov in Act. Hort. Petrop. xxv. 

 200 (Fl. Mandsh. in.) (1907).— Schneider, 111. Handb. Laubholzk. n. 471, 

 figs. 314 a-b, 316 c-f. (1909).— Nakai in Jour. Coll. Sci. Tokyo, xxxi. 75 

 (Fl. Kor. II.) (1911); Fl. Sylv. Kor. pt. vm. 33, t. 9 (1919).— Dallimore in 

 Garden, lxxvii. 18, fig. (1913). — Osborn in Gard. Chron. ser. 3, liii. 51, 

 fig. 26 (1913).— Bean, Trees & Shrubs Brit. Isl. n. 352 (1914).— Rehder 

 in Bailey, Stand. Cycl. Hort. v. 2938 (1916).— Millais, Rhodod. 152 (1917). 



Rhododendron dahuricum 0. roseum DeCandolle, Prodr. vn. 725 (1839). 

 Rhododendron dauricum var. pallidum Regel in Gartenfl. xi. 377 (1862). 

 Rhododendron dauricum «. dauricum Maximowicz in M6m. Acad. Sci. St. 



P6tersb. s£r. 7, xvi. no. 9, 44 (Rhod. As. Or.) (1870).— Matsumura, Ind. 



PI. Jap. ii. pt. 2, 459 (1912). 

 Azalea dahurica K. Koch, Dendr. n. 181 (1872). 

 Rhodora canadensis Beziat in Jardin, xx. 57, figs. 31, 32 (1906), not Linnaeus. 



A much-branched shrub 1-2 m. tall, branches twiggy, ascending, 

 lepidote, bud-scales densely lepidote. Leaves deciduous or persisting 

 through the winter to the late spring, petioled, elliptic* to elliptic-ovate, 

 often lanceolate on free shoots, coriaceous, 1-5 cm. long, 0.6-2 cm. wide, 

 rounded to obtuse, sometimes mucronulate at apex, rounded or narrowed 

 at base, dark green lepidote, finely reticulate above, pale green to rust- 

 brown and densely lepidote below, margin waved. Flowers precocious, 

 solitary or in a cluster at end of the shoot each from separate bud, bright 

 red-purple, 3-3.5 cm. across; peduncle surrounded by persistent bud- 

 scales; calyx minute with 5 deltoid teeth, lepidote; corolla wide-campanu- 



