Rhododendron L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 8-9

5. Rhododendron L. 2

(incl. Azalea L. pro parte)

Shrubs or dwarf shrubs, usually evergreen; leaves alternate, shortly petiolate. Flowers 5-merous, actinomorphic or slightly zygomorphic, in short terminal racemes; bracts scarious, deciduous. Sepals connate at the base, or almost throughout their length, often very small. Corolla campanulate to infundibuliform. Stamens 10, rarely 5; anthers without appendages. Ovary 5-locular; fruit a septicidal capsule; seeds numerous, minute. Literature: J. B. Stevenson (ed.), The Species o f Rhododendron , ed. 2. London. 1947. 1 Deciduous; stamens 5; ovary and immature capsule strigose 1. luteum

1 Evergreen; stamens usually 10; ovary and immature capsule glabrous or lepidote

2 Leaves at least 6 cm, glabrous; ovary and immature capsule glabrous 2. ponticum

2 Leaves not more than 4 cm, hairy or lepidote; ovary and immature capsule lepidote

3 Procumbent; corolla glabrous; stamens 5-8 6. lapponicum

3 Erect; corolla lepidote outside; stamens 10

4 Leaves ciliate 5. hirsutum

4 Leaves not ciliate

5 Leaves acute or mucronate; pedicels glabrous; style about twice as long as ovary 3. ferrugineum

5 Leaves obtuse; pedicels pubescent; style about as long as ovary 4. myrtifolium