52 JOURNAL OF THE ARNOLD ARBORETUM [vol. iv. 



This well-known hybrid is characterised by its broad, funnel-form rose- 

 purple to lilac flowers with corollas about 3.5 cm. across, by its ovate, ciliate 

 calyx-lobes and by its few-flowered clusters. The leaves are persistent, 

 from 2.5-5 cm. long, more or less oval, sparingly ciliate, with rusty-brown 

 lepidote glands on the underside. It is a much more beautiful shrub in 

 flower than R. dauricum Linn, but is less hardy. This is to be expected 

 from the influence of the Himalayan R. ciliatum Hook, f . In the Arnold 

 Arboretum we can keep it alive but the foliage and flowers are usually 



injured every year. 



This hybrid was raised by Mr. Isaac Davies of Ormskirk Nurseries, 

 Wavertree,near Liverpool and was exhibited before the Royal Horticultural 

 Society in 1861, as told in the Gardeners' Chronicle for 1878. 



There are several forms of R. praecox in cultivation including f. 

 grandiflorum Cripps, with larger leaves and flowers, raised at Tunbridge 

 Wells by Messrs. Cripps, and the f . rubrum Hort. so beautifully figured in 

 the Garden, xxxvm. 32, t. 761 (1890). 



A hybrid of the second generation is 



X Rhododendron praecox var. "Early Gem" Rhododendron "Early 

 Gem" Gard. Chron. n. s. ix. 335, fig. 57 [1878] which is R. praecox X /?. 

 dauricum. This has foliage like that of R. dauricum and an inflorescence 

 like X R. praecox but with larger flowers. It was raised at Coombe Wood 

 nurseries by Messrs. Veitch and is figured in the Gardeners' Chronicle, 

 1878. In the Arnold Arboretum its hardiness is not greater than that 

 of R. praecox. 



Subgen. II. AZALEASTRUM Planch. 



Rhododendron subgen. Azaleastrum Planchon in Rev. Hort. 1854, 43. — 

 Maximowicz in Mem. Acad. Sci. St. Petersb. ser. 7, xvi. no. 9, 15 (Rhod. 



Monog 



As. Or.) (1870).— Rehdcr in Wilson & Rehder, 

 (1921). 



Azaleastrum Rydberg in Mem. New York Bot. Gard. i. 297 (1900), as a genus. 

 Represented by 9. R. semibarbatum 



Hutchinson in 



Rhododendron semibarbatum Maximowicz in Bull. Acad. Sci. St. 

 Petersb. s<5r. 3, xv. 230 (Mel. Biol. vn. 338) (1870); in Mem. Acad. Sci. 

 St. Petersb. ser. 7, xvi. no. 9, 45 (Rhod. As. Or.) (1870).— Regel in Gartenfl. 

 xxiv. 292, t. 666 (1870).— Franchet & Savatier, Enum. PI. Jap. i. 293 

 (1875).— Matsumura, Ind. PI. Jap. II. pt. 2, 464 (1912).- 

 Millais, Rhodod. 240 (1917). 



Azalea semibarbata Kuntze, Rev. Gen. u. 387 (1891). 



Azaleastrum semibarbatum Makino in Tokyo Bot. Mag. xxvin. 33S (1914). 



Mumeazalea semibarbata Makino 1. c, as a synonym. 



Shrub 0.3-2 m. tall, branches twiggy, ascending and spreading, pubescent 

 and with long straight gland-tipped hairs. Leaves deciduous, scattered 



