Bot. Mag. (Tokyo) 13: 17 (1899)
Verified by:
Shrub to 2m tall; bark light brown, papery and shredding, revealing polished
brown stems and branches; young twigs pale to red-brown, sparsely covered with
multicellular gland-headed and eglandular hairs; new foliage shoots arising from
axillary buds associated with foliage leaves of the previous year's shoot (i.e. below terminal bud), and some terminal buds. Vegetative bud scales glabrous abaxially, to occasionally with a few multicellular gland-headed and/or eglandular hairs near apex, sparsely to moderately unicellular-pubescent adaxially, especially near apex, and sometimes with a few multicellular gland-headed and eglandular hairs near apex; margin fringed with unicellular hairs distally, becoming glabrous proximally; lowermost scales with apices similar to those of upper scales, not long aristate (although occasionally with rudimentary blade). Leaves deciduous, dark green adaxially, pale green abaxially, turning orange to red in autumn, alternate (with internodes becoming more closely spaced towards tip of shoot). Blade membranaceous, obovate, often broadly so, to rarely broadly elliptic, 4-18 x 1.5-8.5cm; base attenuate, with blade decurrent along basal portion of midvein; apex rarely obtuse, usually rounded to emarginate, with a short mucro; midvein strongly raised and prominent abaxially, the secondary, tertiary, and some higher order veins slightly raised abaxially, thus vein reticulum usually conspicuous; adaxial surface, including midvein, with scattered multicellular gland-headed and eglandular hairs; abaxial surface with scattered multicellular gland-headed and eglandular hairs, the lateral surfaces of midvein very sparsely to moderately fringed with straight to crisped, unicellular hairs, especially near base, or such hairs lacking, and with multicellular gland-headed and eglandular hairs, the secondary veins with scattered multicellular hairs, sometimes sparsely unicellular-pubescent near junction with midvein, especially at base of blade; margin entire to irregularly undulate with a fringe of multicellular eglandular hairs, usually with a few gland-headed hairs intermixed; petiole essentially lacking, the base abruptly expanded into a very broadened point of attachment, forming a ± triangular slight protuberance below terete portion of midvein. Flower bud scales with abaxial surface glabrous, sometimes with a few unicellular hairs or multicellular gland-headed or eglandular hairs near apex, the adaxial surface sparsely to densely covered with unicellular hairs, especially near apex, often with a few multicellular hairs near apex; margin ciliate with unicellular hairs, usually with a few glandular hairs intermixed, to unicellular-ciliate near apex and with closely associated multicellular glandular hairs proximally. Flowers appearing with or after the leaves; inflorescence an umbellate raceme of 6-15 flowers. Pedicels 8-25mm long, moderately to densely covered with multicellular gland-headed hairs. Calyx lobes lingulate to broadly ovate-triangular, 0.9-6 x 1.2-2mm; apex rounded to acute; margin fringed with multicellular gland-headed hairs; adaxial surface glabrous; abaxial surface with scattered multicellular gland-headed hairs, often sparsely unicellular-pubescent near apex. Corolla white, lacking spots, ± actinomorphic, tubular-campanulate, the tube longer than the limb and broadly expanding into it; corolla lobes all ± similar, 0.5-0.9cm long and wide; corolla tube 1-1.6mm long; outer surface of corolla glabrous; inner surface of corolla sparsely unicellular-pubescent towards base. Stamens 10, straight, variable in length, 1.4-2.2cm long, included; filaments glabrous distally, becoming densely covered with flattened unicellular hairs proximally. Ovary 3-5mm long, moderately to densely covered with multicellular gland-headed hairs; style straight, 1.2-1.8cm long, glabrous. Capsules ovoid to ellipsoid, 0.7-1.7x0.5-0.7cm, strongly grooved, moderately covered with multicellular gland-headed hairs. Seeds light yellowish brown, ellipsoid with 5 well-developed longitudinal furrows, 0.6-1 x 0.2-0.35mm; testa tightly appressed to body, with cells at each end elongated and fused to form + stellate tails 0.2-0.5mm long, the cells covering body elongate. Cotyledons lacking multicellular hairs and with venation represented only by midvein.
Japan (north-central Honshu)
Woods and thickets
Azalea nipponica (Matsum.) Copeland, Am. Midi. Nat. 30: 595 (1943). Type: Japan, prov. Uzen, Gassan-hen, 24 vii 1887, S. Okubo & R. Yatabe s.n. (lecto., designated here, TI).
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):24