1916-17.] BOTANICAL SOCIETY OF EDINBURGH 195 



is also but less prominentl}^ wax-coated. These wax-coat- 

 ings in the series require further investigation. As I 

 have pointed out on a preceding page, they are developed 

 in varying degree in several species, being particularly 

 evident in Rh. ceraceitm where the under surface is par- 

 ticularly^ glossy the upper surface less so, and in all the 

 immediate allies of Rh. gymnanthum the under surface 

 has a somewhat shining look from the presence of w^ax. 



Along with Rh. araiopliylluin, Rli. mengtszense, Rh. 

 spanotrichum, and Rh. tanastyhun, the species belongs to 

 that set within the Irroratum series which shows narrow 

 lanceolate or oblanceolate leaves and 5-lobed corolla, glabrous 

 inside and out. Rh. araiopJiyllum is a white-flowered plant 

 with open campanulate corolla and puberulous ovary. Rh. 

 mengtszense is a gland-setose plant and readily differentiated 

 by the character. Rh. spanotrichum has shorter leaves not 

 glossy above, much more definitely oblanceolate, and its 

 corolla is not f unnel-campanulate and its staminal filaments 

 are glabrous. RJt. tanastylum. has also much shorter leaves 

 but glossy above, and the corolla is tubular-campanulate, 

 the stamens glabrous. Diels mentions and Rehder and 

 Wilson also refer to a likeness of RJi. gymnanthum to 

 Rli. lukiangense, but the species are very different (see 

 under Rh. lukiangense, p. 203). 



Rhodixlendron liylofhreptum, Balf. f. et W. W. Sm.^ 



Tree about 9 m. high with thickish branches. Young 

 branches about 8 mm. in diameter densely floccose with 



1 Rhododendron hylothrejitvm, Balf. f. et W. W. Sm. — Arbor ad 9 la. 

 alta raniis suT^crassis. Raniuli hornotini circ. 3 mm. diam. dense 

 floccosi (pilorum ramis brevibus) et clavato-glandulosi glandiili.* rufis vel 

 aiirantiacis, seniores earuni vestigiis vestiti. Alabastrorum elongato- 

 ovoideorum .subviscidorum perulae exteriores late ovatae vel subrotun- 

 datae crn.staceo-coriaoeae brunneae circ. 6 mm. longae ecarinatae baud 

 mucronulatae extus plus minusve rnfo-glandulosae intiis pilii< seliaceis 

 indiitae obscure ciliatae, interiores membrauaceae spathulatae cue. 3 cm. 

 longae circ. 7 mm. latae spadiceo-brnnneae extus pubernlae glandulisque 

 vestitae intus plus minusve puberulae apicem versus sericeae vertice 

 acutatae sebaceo-ciliatae ; folia juvenilia revoluta supra pilis Hoccosis 

 longe ramosis et glandulis clavatis paucis dense induta subtus glandulis 

 clavatis et pilis paucioribus breviter ramosis vestita, margine pilis pede 

 lato praedita ; petiolus juvenilis dense clavato-glandulosus et pilis Hoccosis 

 obtectus. Folia petiolata arl 13 cm. longa ; lamina chartacea lanceolata 

 nunc oblanceolata ad extremitates attenuata ad 11"5 cm. longa ad 3"5 cm. 

 lata apico acuta corneo-tuberculata margine plana cartilaginea obscure 



