512 WILSON EXPEDITION TO CHINA 



lata, supra atroviridia squamulis albidis dense obtecta, subtus albido- 

 cinerea, squamulis pallidis congestis obtecta, costa media supra 

 leviter impressa subtus leviter elevata, nervis secundariis obscuris; 

 petioli dense fusceseenti-lepidoti, 2-3 mm. longi. Flores plerumque 

 solitarii, rarius 2 v. 3 e gemme terminali orti; pedicelli circiter 2 mm. 

 longi, lepidoti, perulis occultati; calyx magnitudini variabili, mem- 

 branaceus, plerumque purpurascens, interdum flavo-virens, pro- 

 funde 5-lobus, lobis plerumque subaequalibus ovatis v. rotundatis 

 2-5 mm. longis et 1.5-3 mm. latis apice rotundatis plerumque sparse 

 ciliatis in media dorsi lepidotis; corolla infundibuliformis, roseo- 

 purpurea, 2.5-3 cm. diam., tubo 6-7 nrni. longo intus ad faucem 

 villoso, lobis late ovatis v. suborbicularibus 10-12 mm. longis et 

 circiter 10 mm. latis; stamina 10, subaequalia, corolla pauUo breviora, 

 filamentis 12.15 mm. longis complanatis in triente inferiore ima basi 

 excepta villosis, antheris fulvis; ovarium conicum, 2 mm. longum, 

 dense lepidotum squamulis viridi-cinereis; stylus stamina superans, 

 1.3-1.5 cm. longus, rubescens, glaber v. sparse lepidotus, interdum 

 infra medium sparse pilosus, stigmate capitato atropurpureo. Cap- 

 sula ovoidea, 4-5 mm. longa, calyce persistente circumdata, dense 

 lepidota, 5-valvata; semina ovalia, circiter 1 mm. longa, fere exalata. 



Western Szech'uan: Tachien-lu, moorlands, alt. 3300-4300 m., 

 June and October 1908 (No. 1225, type); north of Tachien-lu, Ta- 

 p'ao-shan, alt. 4100-4900 m., July 7, 1908 (No. 3462). 



Closely related to Rhododendron polifolium Franchet, which differs chiefly in 

 its narrower, generally oblong leaves and smaller calyx, which does not exceed 

 2 mm. in length. From the preceding species of this group it is easily distin- 

 guished by the uniformly grayish white color of the densely lepidote under side 

 of the leaves. 



We take much pleasure in naming this species for Mr. Frank G. Webster of 

 Boston, as a slight mark of appreciation of his constant generosity to the Arnold 

 Arboretum and of his invaluable help in the arrangement of its Chinese expeditions. 



Group d. 



Flowers like those of the preceding group, but yellow. Leaves somewhat larger 

 with scattered scales beneath, more densely lepidote above. 



Rhododendron flavidum Franchet in Jour, de Bot. IX. 395 (1895). — 

 Hemsley in Bot. Mag. CXXXVI. t. 8326 (1910). — Hemsley & 

 Wilson in Kew Bull. Misc. Inform. 1910, 117. — Schneider, III. 

 Handb. Laubholzk. II. 1045, fig. 614 c-d (1912). 



Rhododendron primulinum Hemsley in Gard. Chron. ser. 3, XLVII. 4, 229, 

 fig. 101 (1910). 



