538 WILSON EXPEDITION TO CHINA 



The open campanulate flowers with the large calyx, leaves cordate or truncate 

 at the base, with a metallic-green luster, readily distinguish R. Souliei from all 

 related species. 



Rhododendron Williamsianum Rehder & Wilson, n. sp. 



Frutex 1.50 alius, ramosu; ramuli graciles, hornotini sparse 

 pilis glanduliferis instruct!, annotini glabri, nitiduli, pallida cinereo- 

 fusci; gemmae ovoideae, acutae, purpurascentes, perulis extus glabris 

 ciliolatis. Folia coriacea, ovata v. rotundato-ovata, apice rotundata 

 apiculata, basi plerumque leviter cordata, rarius truncata, margine 

 reflexa, 1.7-4.2 cm. longa et 1.3-3.2 cm. lata, glabra, supra obscure 

 viridia, leviter elevato-reticulata, subtus flavescenti-glauca, obsolete 

 elevato-reticulata; petioli 1-1.5, saepe sparsissime glanduloso-pilosi, 

 purpurascentes. Flores 3-5, umbellato-racemosi ; pedicelli sparse 

 glanduloso-pilosi, purpurascentes, interdum glabri; calyx minutus, 

 obsolete 5-dentatus, sparse stipitato-glandulosus praesertim ad mar- 

 ginem; corolla aperte campanulata, 3-3.5 cm. longa et 4-4.5 cm. 

 lata, glabra, pallide rosea maculis destituta, 5-loba lobis suborbicu- 

 laribus 1.2-1.4 cm. longis; stamina plerumque 10, longiora medium 

 loborum attingentia, filamentis glabris; ovarium conicum, glanduloso- 

 pilosum, 4-5 mm. longum; stylus curvatus, exsertus, totus sparse 

 glandulosus glandulis infra medium stipitatis, stigmate capitato, 

 Capsula cylindrica, circiter 1.5 cm, longa, 5 mm. diam., glabra v. 

 sparse glandulis stipitatis instructa, pallida; semina cinnamomea, 2- 

 2.5 mm. longa, utrinque alata. 



Western Szech'uan: Wa-shan, thickets covering cliff, rare, alt. 

 2800 m., June and October 1908 (No. 1350). 



This pretty and distinct species is apparently most nearly related to R. Souliei 

 Franchet, which is easily distinguished by its rather large membranous calyx, 

 differently shaped flowers and larger leaves, merely pale below. It may also be 

 compared with R. rotundifolium David, which is a much more vigorous species, 

 easily distinguished by its totally different leaves and 7-lobed corolla. This new 

 species is apparently very local, occurring only in isolated places on the cliffs of 

 Wa-shan. 



This species is named for Mr. J. C. Williams of Caerhays Castle, Cornwall, 

 England, the first amateur to appreciate the horticultural value of the Rhodo- 

 dendrons of western China; in his garden the best collection of these new intro- 

 ductions is now to be found. 



To this group also belong the following species: 



Rhododendron Purdomii Rehder & Wilson, n. sp. 



Frutex robustus ramulis crassis junioribus puberulis; gemmae perulis ovahbus 

 V. oblongis puberulis per plures annos persistentibus. Folia coriacea, oblongo- 

 lanceolata v. oblonga, acuta, basi cuneata, margine revoluta, 6-9 cm. longa et 

 2.5-3.5 cm. lata, utrinque glabra, supra laeta viridia, nitida, leviter rugulosa, 



