Rhododendron L.
Evergreen or deciduous trees, shrubs, or prostrate shrublets, sometimes epiphytic, either scaly (lepidote rhododendrons) or lacking scales (elepidote rhododendrons). Lvs alternate, entire or rarely ± serrulate, petiolate. Fls mostly in terminal panicles, racemes or umbels, much less commonly axillary or solitary, pedicellate, with deciduous scales (perulae). Calyx 5-(10)-lobed, accrescent but sometimes reduced to a rim. Corolla 5-(10)-lobed, very variable in shape but generally campanulate, funnelform or broadly tubular, usually slightly zygomorphic. Stamens usually 5-10, sometimes more, commonly twice as many as corolla lobes, included or exserted; anthers with apical pores. Fr. a woody septicidal capsule, usually ovoid to oblong. Seeds numerous, minute.
700-800 spp., N. temperate regions, especially tropical and subtropical S.E. Asia and Malesia, 1 sp. in N. Queensland. Naturalised sp. 1.
Well over 200 Rhododendron spp. and a host of horticultural hybrid clones are cultivated in N.Z. Spp. of this enormously variable genus range from prostrate or decumbent shrublets with small lvs and fls often < 1 cm long, to small or medium-sized trees with large lvs up to 1 m long and fls up to c. 12 cm long. In addition to the sp. below one of the most conspicuous and common rhododendrons throughout N.Z. is the hybrid cv. 'Sir Robert Peel' (believed to be a clone of R. arboreum Smith × R. caucasicum Pallas), an evergreen tree with large racemose trusses of pink fls in winter.
