Fl. N. Middle United States 1:425 (1824)
WFO ID: wfo-0001047065
IPNI ID: urn:lsid:ipni.org:names:30159718-2
Verified by:
Shrub or small tree to 10m tall, usually non-rhizomatous; young twigs reddish brown, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs. Vegetative bud scales glabrous abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (4.5-)5.6-7.7(-9.1) x (1.3-)1.8-2.6(-3.3)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely covered with multicellular eglandular and unicellular hairs or with only multicellular eglandular hairs, or glabrous; the midvein densely covered with unicellular hairs; abaxial surface sparsely to densely covered with multicellular eglandular hairs or glabrous; the midvein densely covered with unicellular and multicellular eglandular hairs,rarely densely covered with unicellular hairs and multicellular eglandular hairs, or with only unicellular hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0.3-0.6(-0.7)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface glabrous, rarely very sparsely covered with unicellular hairs; margin glandular. Flowers appearing before or as the leaves expand; inflorescence a shortened raceme of 5 to 9 flowers. Pedicels (0.7-)0.8-L2(-1.4)cm long, sparsely to densely covered with unicellular hairs and densely covered with multicellular gland-tipped hairs, or with multicellular eglandular hairs, or both. Sepals (0.1-)0.2-0.3cm long, often varying in length on the same flower; margins glandular-fimbriate, frequently setose; abaxial surface sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs or with only unicellular hairs. Corolla orange to flame-coloured, fragrance acrid, the tube longer than the limb and abruptly expanding into it; upper corollalobe (1.4-)1.6-2.2(-2.3) x (1.2-)1.5-2.2(-2.5)cm; lateral lobes 1.8-2.6(-3.0) x (0.9-)1.0-1.4(-l .5)cm; corolla tube (1.6-) 1.8-2.2(-2.4)cm long, (0.2-)0.3-0.4(-0.5)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs and densely covered with multicellular gland-tipped hairs which often continue up the corolla lobes; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (5.2-)5.7-6.7(-7.2)cm long, with dense terete or flattened unicellular hairs on proximal (1.9-)2.3-3. l(-3.2)cm of filament, exserted (3.4-)3.7-4.8(-5.4)cm beyond throat of corolla. Style (5.5-)5.9~6.8(-7.2)cm long, exserted (3.8-)4.2-5.3(-6.0)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-) 0.3-1.3(-1.7)cm; stigma 0.1-0.2(-0.3)cm wide. Ovary 0.3-0.4(-0.5)cm long, (0.1-)0.2-0.3cm wide at the base, densely covered with multicellular eglandular hairs and dense unicellular hairs, rarely with multicellular gland-tipped hairs and unicellular hairs, or with all three types of hairs. Capsules (1.5-)1.8-2.6(-2.9) x (0.5-)0.6-0.8(-0.9)cm, ovate, sparsely covered with unicellular hairs and sparsely to moderately covered with either multicellular eglandular hairs or less often eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.7-)2.4-3.9 (-4.2) x (0.6-)0.9-1.5(-1.9)mm, body (0.8-)l.l-1.7(-2.1) x (0.2-)0.4-0.7(-0.8)mm, the testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate, with transverse end-walls.
USA: Northern West Virginia, south through the mountains of Virginia, North Carolina, Tennessee and Georgia. Generally restricted to the Ridge and Valley Province and Southern Appalachians, with occasional populations in the Cumberland Mountains and in the eastern edge of the Cumberland Plateau in Ohio and Kentucky. Not known west of die Tennessee River Valley in Tennessee. Extending into the Upper Piedmont in North and South Carolina and as far soutii as Meriwether Co., Georgia. Collections from Tarrytown, New York that are R. calendulaceum have been suggested as native in the past (Barnhart, 1895). However, all of the collections are nearly a century old and this is well north of the range of the species. Most likely these were cultivated plants that had persisted.
Found in open, dry sites on southern and western exposures of hills and mountain-sides.
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):296