Rhododendron rex ssp. fictolacteum

Description with 26 photos. Photo: Finn Bertelsen.

FB22-2018

A tall, upright shrub or small tree, 4-5 m high, evergreen. Young shoots (and buds) light brown/grey white tomentose, eglandular, 10-11 mm in diameter. Terminal buds with long, tapering, revolute bud scales. Petiole terete, tapering, brown tomentose, 5-7 mm thick, to 32 mm. Leaf blade narrow elliptic to oblanceolate, to 24 x 6 cm (4:1). Apex obtuse with tiny mucro. Leaf base cuneate, obtuse to truncate or subcordate. Leaf upper side initially white/fawn floccose, later glabrous, dark green. Leaf lower side with bi-strate indumentum: Upper layer cinnamon brown, velvety by dense, stipitate, cup-shaped hairs with marginal lobes distally tapering into winding, hair-like prolongations. Diameter of cup-shaped hairs: 350 – 475 micrs. Lenght of margin extensions: c. 400 micrs. Length of hair stalk: to 350 micrs. Lower layer white, compact, with  hair elements  10 – 15 micrs. Inflorescence an umbel-like raceme with c. 15 – 20 flowers. Pedicel floccose, to 32 mm. Calyx floccose, disc-like, 2.4 mm, including 7 smalle, rounded lobes, c. 0.9 mm. Corolla etc. unknown. Capsule with scattered tufts of dendroid hairs, easily worn away leaving a dotted, glabrous surface, curved cylindrical, with 8 loculi, to 35 x 8 mm.Seeds with well developed floating sacs and wings, 2.4 – 3.5 mm. Locality of origin: Zhongdian County, Yunnan, China at 3600 m.

‘Bangsbo’

As above, but with atypical broad leaves: to 24.0 x 10.5 cm (2.3:1). Calyx floccose, a few mm, with 7 rounded lobes < 1 mm. Corolla with 7 lobes, campanulate, glabrous, white with crimson blotch, 50 mm wide, 35 mm deep (long). Ovary densely tomentose by white dendroid hairs, with 7 – 8 loculi. Stamens 14 – 15, unequal in length, proximally pubescent including glandular hairs, to 28 mm. Style glabrous, slightly upward bent, to corolla margin (30 mm), with yellow turbinate stigma, 2.6 mm. Origin: Present from Bangsbo Botanical Garden, Frederikshavn, Denmark, from Yunnan seeds.

Occurrence of ssp. fictolacteum: SW Sichuan, SE Xizang, NW Yunnan, (NE Myanmar) at 2900-4000m according to Flora of China.