504 WILSON EXPEDITION TO CHINA 



Rhododendron Sargentianum Rehder & Wilson, n. sp. 



Frutex 30-60 cm. altus, ramosiosimus ramis erectis v. adscendenti- 

 bus; ramuli hornotini et aiinotini fusco-tomentosi, tarde glabrescentes, 

 vetustiores cinereo-fusci, cortice in lamellas tenues solubili et corticem 

 interiorem flavido-cinereum detegente; gemmae parvae, ovoideae, 

 acutae, perulis paucis acutis tomentosis ciliatis erectis et per plures 

 annos persistentibus. Folia coriacea, aromatica, ovalia, obtusa et 

 mucronulata, basi late cuneata, 8-15 mm. longa et 5-8 mm. lata, 

 margine revoluta, supra initio lepidota, mox glabra, atroviridia, leviter 

 rugulosa, subtus dense tomento sublepidota fusco-ferrugineo, initio 

 flavido obtecta, costa media supra impressa subtus elevata, nervis 

 secundariis obsoletis; petioli 2-4 mm. longi, lepidoti. Flores 6-12, ter- 

 minales, umbellato-racemosi ; pedicelli 5-7 mm. longi, flavido-lepidoti ; 

 bracteae pedicellis subaequilongae, oblongae, ciliatae, utrinque pubes- 

 centes, partim persistentes, calyx conspicuus, membranaceus, viridi- 

 flavus, lobis 5 oblongo-obovatis 3-4 mm. longis 1-1.5 cm. latis 

 rotundatis sursum ciliatis extus lepidotis intus puberulis; corolla hypo- 

 crateriformis, albida v. pallide lutea, extus lepidota et sparse pubescens, 

 tubo cylindrico 6-7 mm. longo intus villoso praesertim faucem versus, 

 subito in limbum erecto-patentem ampliatum, lobis suborbicularibus 

 4-6 mm. longis et 5-7 mm. latis; stamina 5, plerumque tubo paullo 

 breviora, filamentis circiter 4 mm. longis basi dilatatis glabris, antheris 

 ovoideis ochraceis; ovarium subglobosum, circiter 1 mm. longum, 

 dense flavido-lepidotum; stylus staminibus paullo brevior, glaber, 

 sursum incrassatus, stigmate capitato. Capsula subglobosa, circiter 

 4 mm. longa, lepidota, 5-valvata, stylo persistente, basi calyce per- 

 sistente suffulta; semina flavido-brunnea, nitida, ovoidea, 1 mm. 

 longa, utrinque acuta, fere exalata. 



Western Szech'uan: Mupin, growing on exposed rocks, alt. 

 3000-3600 m., June and October 1908 (Nos. 1208, type, 3454); 

 same locality, alt. 4000-4300 m., October 1910 (No. 4237); Wa- 

 shan, cliffs, 3300 m., July 1903 (Veitch Exped. No. 3933); without 

 precise locality, October 1904 (Veitch Exped. No. 3931 and seed 

 No. 1888). 



This new species belongs to a small group which includes R. anthopogon D. Don, 

 R. anthopogonoides Maximowicz, R. rufescens Franchet, R. cephalanthum Fran- 

 chet and two or three other species from all of which it is readily distinguished by 

 its lepidote corolla. All the species are very closely allied, having white or pale 

 yellow flowers and are all strictly alpine plants. In this new species the longer 

 pedicels and shorter bracts render the calyx more clearly visible than it is in other 

 species. 



