42 JOURNAL OF THE ARNOLD ARBORETUM [vol. iv. 



growing in 1918, but personally I have never seen a healthy plant in 

 gardens. Bean comments on its bad behavior in England and that it is 

 not figured in the Botanical Magazine proves it is either a rare plant or 

 difficult to grow in England. 



This species has been known for a long time and seems to have been 

 first collected by D. G. Messerschmidt in Russian Dahuria sometime 

 between 1720 and 1727. Very soon after it was observed by Messrs. 

 Gmelin & Steller in the valley of the Lena River and eastward. Gmelin 

 in his Fl. Sib. IV. 121, t. 54 (1769) refers to it as "Andromeda foliis ovatis, 

 utrinque venosis, corollis campanulatis obliquis longissimis." Pallas in 

 his travels in Siberia met with it and very probably it was he who intro- 

 duced it into Russia. In 1796 it was introduced into England from 

 Russia by Mr. Joseph Busch. Millais (Rhodod. 143) claims that after 

 the introduction in 1803 of R. caucasicum Pall, the early hybridisers in 

 Scotland raised numerous hybrids between it and R. chrysanthum 

 many of which are now among our most valuable spring Rhododendrons. 

 He mentions (p. 139) R. caucasicum var. stramineum Hook, and R. cau- 

 casicum var. flavidum Nicholson. I can find no trustworthy evidence in 

 support of this and am of the opinion that R. chrysanthum has played 

 no part in the production of the so-called "Caucasicum Hybrids" or, 

 indeed, in the production of any hybrid Rhododendron. The early writers 

 confused R. chrysanthum with the yellow-flowered form of R. Caucasi- 

 an Pall, and it is this plant that figures in the Rhododendrons mentioned 

 by Millais. 



To the hunters in Siberia R. chrysanthum was famous as a medicine. 

 An infusion of the young leaves was considered a cure for rheumatism. 

 It was also recommended in venereal diseases. On this account much was 

 written about it toward the close of the 18th and early in the 19th cen- 

 turies and it is beautifully figured in several of the works cited, especially 

 Hooker's figure in his Paradisus Londinensis. 



Sect. 2. LEPIPHERUM G. Don. 



Rhododendron sect. Lepipherum (i. Don, Gen. Syst. m. 845 (1834). 



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

 Petersb. s6r. 7, xvi. 9, 14 (Rhod. As. Or.) (1870), in part. 



KEY TO TI IE SPECIES 



Bud-scales deciduous. 



Flowers white; corolla rotate-campanulate; filaments glabrous. 



4. R. micranthum. 

 Flowers pale yellow; corolla broad-campanulate; filaments slightly pilose at 

 base 5. R. Kciskei. 



Bud-scales persistent. Flowers rose-purple; corolla wide-campanulate; fila- 

 ments villose at base 6. R. yarvijolium . 



Rhododendron micranthum Turczaninow in Bull. Soc. Nat. Mosc. x. 

 no. 7, 155 (1837); in xxi. pt. 2, 502 (Fl. Baical. Dahur.) (1848).— De 



