Rhododendron ambiguum

Description with 27 photos. Photo: Finn Bertelsen. A dense, but delicately built, a few meter high, evergreen shrub. Fully hardy. Young shoots with dark scales. Petiole with dark scales, 5 – 8 mm. Leaf blade elliptic, aromatic, to 6 cm. Apex acute to acute-obtuse, with mucro. Leaf base obtuse to acute. Leaf adaxial side dark green, shiny, with scattered small scales, c. 140 micrs., 1 – 2 x their diam. apart, pubescent on the midrib. Leaf abaxial side whitish grey-green, glaucous, papillose, densely scaly. Scales 0 – 1 x their diam. apart. Two types of scales (magnifying-glass / microscope neaded): Large, dark scales, 285 – 340 micrs.; smaller light brown scales, 230 – 240 micrs. Inflorescense with 4 – 5 (6) flowers, with rachis < 5 mm. Pedicel with scattered scales, 8 – 14 mm. Calyx densely scaly, with exception of the margin, with rounded lobes, 2 – 3 mm. Corolla with 5 lobes, open funnel-campanulate, zygomorphic, light yellow with green spots, with a few external scales, to 40 mm wide and 15 mm deep. Ovary conical, densely scaly, channelled, with 5 loculi, 4 – 5 mm. Stamens 10, unequal, densely hairy-glandular hairy towards base. Style green, upwards bent, 30 – 35 mm, with slightly turbinate, bullate stigma, 1.3 mm. Capsule scaly, cylindrical, 10 -15 mm x 2 – 3 mm. Seeds with tiny floating appendages, (CW) 1.3 – 1.6 mm, in the garden specimen 1.6 – 2.0 mm. Native habitat: C. and W. Sichuan, China, at 2300 – 3300 (-4500) m according to Flora of China efloras org.