QBARS - v29n3 Two New Rhododendrons

Two New Rhododendrons
H. H. Davidian, Edinburgh, Scotland

Rhododendron flinckii Davidian, sp. nov.
Species R. lanato Hook. f. affinis sad foliis infra indumento tenui pannoso rufo-brunneo, lamina tenui, pilis dissimilibus recedens.

Frutex 1.50-2.45 m. altus; ramuli dense tomentosi, tomento rufo-brunneo, pallide brunneo vel albido, eglandulosi, sub inflorescentia 3-5 mm. diametro, perulis deciduis. Folia sempervirentia; lamina oblongo-ovalia, oblongo-lanceolata, oblongo-elliptica vel elliptica, 4-9.8 cm. longa, 2-4.4 cm. lata, apice breviter acuminata vel obtusa, basi rotundata vel obtusa, supra atroviridis nitens vel opaca, glabra (in foliis juvenilibus dense tomentosa), costa media sulcata dense tomentosa, venis primariis 6-15 impressis, infra indumento tenui pannoso rufobrunneo, costa media prominente dense tomentosa, venis primariis elevatis; petiolus 0.5-1.8 cm. longus, dense tomentosus tomento rufo-brunneo, pallide brunneo vel albido, eglandulosus. Inflorescentia breviter racemoso-umbellata 3-8- flora, bracteis deciduis; rhachis 3-8 mm. longa, dense vel moderate tomentosa, tomento brunneo, eglandulosa; pedicelli 0.5-1.6 cm. longi dense tomentosi tomento albido, pallide brunneo vel brunneo. Calyx annularis tantum vel 5-lobatus, minutus, 0.5-1 mm. longus, lobis triangularibus vel ovatis, extra et margine glabris vel dense vel moderate tomentosis eglandulosis. Corolla campanulata, 3.5-5 cm. longa, lutea postice kermesino-maculata; lobi 5, 1.5-2.3 cm. longi, 1.5-3 cm. lati, rotundati emarginati. Stamina 10 inaequalia, 1.5-3 cm. longa, corollae breviora; filamenta basi dense pubescentia. Gynoecium 3-3.6 cm. longum, corollae brevius; ovarium conoideum vel oblongum, 5-6 mm. longum, 5-loculare, dense tomentosum, tomento brunneo, pallide brun

neo vel albido, eglandulosum; stylus glaber eglandulosus.

Bhutan. Kopub. Pumthang. Bush 8 feet in Abies forest. Scarce. Alt. 10,000 feet. 18/6/1915. R.E. Cooper No. 3990 (Holotype in Herb. Hort. Bot. Edin. Details of the flower are taken from a cultivated plant).

This plant was first found by R. E. Cooper in June 1915 at Kopub, Pumthang, in Bhutan. It grows in Abies forest at an elevation of 10,000 feet.

R. flinckii is a member of the Campanulatum Series. It is allied to R. lanatum from which it is readily distinguished by the thin, felty, rusty brown indumentum on the lower surfaces of the leaves, by the thin texture of the leaves, and somewhat by the structure of the hairs.

The species was introduced into cultivation by Ludlow and Sherriff in 1936. It is hardy, but to obtain the best results a sheltered position should be provided.

I have named this species after Mr. K. E. Flinck, in recognition of his outstanding contributions to the cultivation of rhododendrons in Sweden.

A shrub, 1.50-2.45 m. high; branchlets densely tomentose with rusty-brown, fawn or whitish cottony tomentum, eglandular, those below the inflorescences 3-5 mm. in diameter, leaf-bud scales deciduous. Leaves evergreen, oblong-oval, oblong-lanceolate, elliptic or oblong-elliptic, lamina coriaceous, somewhat thin, 4-9.8 cm. long, 2-4.4 cm. broad, apex shortly acuminata or obtuse, base rounded or obtuse; upper surface dark green, shining or somewhat mat, glabrous or with vestiges of hairs, (in young leaves densely hairy with rusty-brown or whitish hairs), midrib grooved, densely woolly in its entire length or in the lower half, primary veins 6-15 on each side, deeply impressed; under surface covered with a somewhat thin, felty, rusty-brown, continuous indumentum of hairs, (in young leaves whitish or bright rustybrown), midrib prominent, densely hairy, primary veins raised; petiole 0.5-1.8 cm. long, densely tomentose with rusty brown, fawn or whitish cottony tomentum, eglandular. Inflorescence a shortly racemose umbel of 3-8 flowers flower-bud scales deciduous; rhachis 3-8 mm. long, densely or moderately tomentose with brown tomentum, eglandular; pedicels 0.5-1.6 cm. long, densely tomentose with whitish, fawn or brown cottony tomentum. Calyx a mere rim or 5-lobed, minute, 0.5-1 mm. long, lobes triangular or ovate, outside and margin glabrous or densely or moderately hairy, eglandular. Corolla campanulate, 3.5-5 cm. long, yellow, with crimson spots on the posterior side; lobes 5, 1.5-2.3 cm. long, 1.5-3 cm. broad, rounded, emarginate. Stamens 10, unequal, 1.5-3 cm. long, shorter than the corolla; filaments densely pubescent at the base. Gynoecium 3-3.6 cm. long, shorter than the corolla; ovary conoid or oblong, 5-6 mm. long, 5 celled, densely tomentose with brown, fawn or whitish tomentum, eglandular; style glabrous, eglandular.

Rhododendron rubroluteum Davidian, sp. nov.

Species R. melinantho Balf. f. et Ward affinis sed corolla rubrolutea postice dense kermesino-maculata late infundibuliformis zygomorpha, foliis sempervirentibus supra caesio-glaucis, pedicellis et calycis margine dense setulosis differt.

Frutex 90 cm.-1.70 m. altus; ramuli lepidoti, setulosi, perulis deciduis. Folia sempervirentia; lamina obovata, oblonga vel oblongo-elliptica, 3-5.8 cm. longa, 1.3-2.6 cm. lata, apice rotundata vel obtusa et mucronata, basi rotundata, obtusa vel cordulata, supra caesio-glauca, opaca, elepidota vel paulo lepidota, esetulosa, margine esetulosa, infra pallide glauco-viridis, squamis inaequalibus minutis atrobrunneis vel pallide brunneis inter se 2-3 diametris distantibus praedita, esetulosa; petiolus 2-3 mm. longus, lepidotus, sparsim setulosus vel esetulosus. Inflorescentia terminalis, vel terminalis et foliis summis 1-2 axillaris, breviter racemosa 3-5-flora, bracteis deciduis; rhachis 3-5 mm. longa, lepidota, pubescens vel glabra, sparsim setulosa vel esetulosa; pedicelli 2-2.4 cm. longi lepidoti, moderate vel dense setulosi. Calyx 5-lobatus, minutus 0.5-1 mm. longus, lobis ovatis, extra lepidotis vel elepidotis esetulosis, margine lepidotis vel elepidotis dense setulosis. Corolla late infundibuliformis zygomorpha, 1.8-2 cm. longa, 5-loba, rubrolutea postice dense kermesino-maculata, extra lepidota glabra. Stamina 10 inaequalia longe exserta, 1-1.7 cm. longa; filamenta basi vel ad medium pubescentia. Ovarium conoideum vel ovoideum, 2-4 mm. longum, 5-loculare, dense lepidotum, glabrum; stylus curvatus vel rectus, elepidotus, glaber. Capsula oblonga, 6-9 mm. longa, 3-4 mm. lata, recta, dense lepidota, glabra, calyce persistente.

Yunnan-Szechwan-Tibet and N.E. Upper Burma. Bush of 3-5 feet. In grassy pastures and on open granite slopes amidst bamboo thickets. As above at 12,000 feet. November 1922. Series Trichocladum. F. Kingdon-Ward No. 5489 (Holotype, cultivated specimen under F. Kingdon-Ward No. 5489 in Herb. Hort. Bot. Edin.).

Kingdon-Ward discovered this plant in the course of his expedition of 1922 to Yunnan-Szechwan-Tibet and N.E. Upper Burma. It is found in grassy pastures and on open granite slopes at an elevation of 12,000 feet. The exact locality of this plant has not been recorded.

R. rubroluteum is a distinctive species belonging to the Trichocladum Series. It is related to R. melinanthum from which it differs markedly in that the corolla is reddish-yellow with numerous crimson spots on the posterior side, widely funnel-shaped, zygomorphic, the leaves are evergreen, bluish glaucous on the upper surface, the pedicel and calyx margin are rather densely bristly. In cultivation the species is hardy, and is well worth a place in every collection of rhododendrons.

A shrub, 90 cm.-1.70 m. high; branchlets scaly, bristly, leaf-bud scales deciduous. Leaves evergreen, obovate, oblong or oblong-elliptic, lamina 3-5.8 cm. long, 1.3-2.6 cm. broad, apex rounded or obtuse, mucronate, base rounded, obtuse or cordulate; upper surface bluish, glaucous, mat, not scaly or slightly scaly, not bristly; margin not bristly; under surface pale glaucous green, scaly, the scales unequal, minute, dark or pale brown, 2-3 times their own diameter apart, not bristly; petiole 2-3 mm. long, scaly, sparsely bristly or not bristly. Inflorescence terminal, or terminal and axillary in the uppermost one or two leaves, shortly racemose, 3-5-flowered, flower-bud scales deciduous; rhachis 3-5 mm. long, scaly, pubescent or glabrous, sparsely bristly or not bristly; pedicels 2-2.4 cm. long, scaly, moderately or rather densely bristly. Calyx 5-lobed, minute, 0.5-1 mm. long, lobes ovate, outside scaly or not scaly, not bristly, margin scaly or not scaly, rather densely bristly. Corolla widely funnel-shaped, zygomorphic, 1.8-2 cm. long, 5-lobed, reddish yellow, with numerous crimson spots on the posterior side, outside scaly, glabrous. Stamens 10, unequal, longexserted, 1-1.7 cm. long; filaments densely pubescent at the base or up to one-half of their length. Ovary conoid or ovoid, 2-4 mm. long, 5-celled, densely scaly, glabrous; style bent or straight, not scaly, glabrous. Capsule oblong, 6-9 mm. long, 3-4 mm. broad, straight, densely scaly, glabrous, calyx persistent.