Rhododendron maximum

Description with 24 photos. Photo: Finn Bertelsen. A  large shrub or small tree, evergreen. Hardy. Young shoots and petioles covered by a thin, greyish, hairy and glandular tomentum, later decaying. Petiole to 28 mm. Leaf blade oblong elliptic to oblanceolate, to 20 cm. Leaf apex, acute with mucro. Leaf base acute to cuneate. Leaf adaxial side dark green, glabrous, with remains of glandular hairs on the midrib. Leaf abaxial side with a greyish to brownish, thin, plastered indumentum consisting of radiate hairs with wings about 150 micrs. long. Some leaves with almost none or restricted indumentum. Late flowering (July) after new growth of shoots. Inflorescence with more than 10 flowers. Pedicels 30 – 40 mm, glandular hairy. Calyx with 5 lobes, c. 3 mm, with rounded lobes covered by  stipitate glands. Corolla with 5 lobes, campunulate, white with yellowish blotch. Ovary densely covered by short-stipitate glands. Stamens (9) 10, unequal in length. Filaments pubescent towards base. Style glabrous, shorter than stamens, c. 20 mm, with swollen yellow-red stigma. Seeds with well-developed floating appendages and narrow wings, 2.6-3.4 mm. Native habitat: The eastern part of USA (Appalachians) according to Flora of North America efloras org.