19231 WILSON, THE RHODODENDRONS OP NORTHEASTERN ASIA 41 



St. PStersb. ix. 189 (Prim. Fl. Amur.) (1859); in Mem. Acad. Sci. St. 

 P^tersb. ser. 7, xvi. no. 9, 20 (Rhod. As. Or.) (1870).— Fr. Schmidt in 

 Mem. Acad. Sci. St. Petersb. ser. 7, xn. no. 2, 55 (Reis. im Amur-1.) 

 (1868).— Komarov in Act. Hort. Petrop. xxv. 205 (Fl. Mandsh. in.) 

 (1907).— Schneider, 111. Handb. Laubholzk. n. 481 (1909).— Nakai in 

 Jour. Coll. Sci. Tokyo, xxxi. 74 (Fl. Kor. n) (1911); Fl. Sylv. Kor. pt. 

 vin. 40. t. 13 (1919).— Bean, Trees & Shrubs Brit. Isl. n. 349 (1914). 

 Matsumura, Ind. PI. Jap. II. pt. 2, 459 (1912).— Miyabe & Miyake, Fl. 

 Sachal. 310, no. 385 (1915).— Millais, Rhodod. 143 (1917). 



Rhododendron officinale Salisbury in Hooker, Parad. Londin. n. t. 80 (1807). 



Shrub 0.2-1 m. tall, much-branched, bark scaly, branches stout clothed 

 with old persistent bud-scales. Leaves stoutly petioled, coriaceous, 

 glabrous, except for slight pubescence on petiole, shining green, elliptic- 

 to ovate-lanceolate, often broadest above the middle, 2.5-8 cm. long, 

 1 -3.5 cm. wide, rounded and mucronulate at apex, narrowed at base, margin 

 slightly recurved, rugulose with impressed veins above. Flowers pale 

 yellow, 5-8, in terminal umbels, wide-campanulate, 2.5-3 cm. across, 

 pedicels rigid, erect, 4-6 cm. long, subtended by persistent bud-scales, 

 clothed with tawny floccose tomentum; calyx pubescent, minute, saucer- 

 shape, with 5 rounded teeth; corolla 5-lobed, lobes spreading, rounded; 

 stamens 10, shorter than corolla, filaments flattened, villose at base; pistil 

 exceeding the stamens, ovary ovoid, furrowed, clothed with ferruginous 

 villose tomentum, style glabrous, curved below the capitate, lobed stigma. 

 Fruit erect, dark brown, ovoid to oblong-ovoid, 0.8-1.4 cm. long, gla- 

 brescent, seeds shining brown, winged at each end. 



Habitat. Altai mountains eastward through Siberia to Kamtschatka, the 

 Kurile Islands and Saghalien; Japan, Hokkaido southward through Hondo to 

 the high mountains of Shinano province; also in Korea. 



This wide-spread species is distinguished by its glabrous rugulose 

 leaves, its umbellate yellow flowers on long erect pedicels and by the long- 

 persistent bud-scales which clothe the shoots. It is most closely related 

 to R. caucasicum Pall, but the yellow-flowered form of that species has 

 leaves markedly hairy on the underside and the flower-truss has an 

 elongate rachis. In Hokkaido and north Korea where I have seen R. 

 chrysanthum wild it has always been on the upper slopes of volcanic 

 mountains. In Hokkaido within the crater of Shiribeshe-san at about 

 6000 ft. altitude I gathered it in flower on July 27, 1914, with unmelted 

 snow a few feet away. As I know it the species is a much-branched 

 shrub from a few inches to 3 feet high; often it forms dense low thickets 

 covering large areas on bare mountain slopes. I never saw any variation 



in color of the flowers and except that it is an alpine plant I see no reason 



why it should not thrive in our gardens. So far all efforts to grow it 

 in the Arnold Arboretum have failed. Seeds I collected in Hokkaido and 

 Korea germinated freely but after struggling for a while the seedlings all 

 died. In the Proctor Arboretum at Topsfield, Massachusetts, it was 



