Rhododendron atlanticum (Ashe) Rehder

Monogr. Azaleas 147 (1921)

WFO ID: wfo-0001047062

IPNI ID: urn:lsid:ipni.org:names:331975-1

Verified by:

Description

Shrub or small tree usually less than l(-3)m tall, very strongly rhizomatous; young twigs red-brown, rarely yellow-brown, sparsely to densely covered with multicellular eglandular hairs or with multicellular gland-tipped hairs, occasionally also with unicellular hairs, rarely with unicellular and multicellular eglandular and gland-tipped hairs. Vegetative bud scales sparsely to densely covered with unicellular hairs or glabrous abaxially; margin unicellular-ciliate, occasionally ciliate and glandular, rarely completely glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (3.2-)3.4-4.7(-5.2) x (0.8-) 1.1-1.9(-2.0)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, occasionally sparsely covered with unicellular and multicellular gland-tipped hairs, or with only multicellular gland-tipped hairs, rarely densely covered with only unicellular hairs, the midvein densely covered with unicellular hairs; abaxial surface glabrous, often paler than the adaxial surface, rarely also glaucous, occasionally with scattered multicellular gland-tipped hairs, rarely with scattered multicellular gland-tipped hairs and unicellular hairs or scattered multicellular eglandular hairs, or densely covered with unicellular hairs, the midvein with multicellular eglandular or gland-tipped hairs, occasionally also with unicellular hairs, rarely with multicellular eglandular and gland-tipped hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0. l-0.4(-0.5)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, or with unicellular hairs and multicellular gland-tipped hairs, or with only multicellular eglandular and gland-tipped hairs, rarely with all three types of hairs. Flower bud scales chestnut brown; abaxial surface sparsely to densely covered with unicellular hairs, frequently glabrous; margin unicellular-ciliate, rarely unicellular above and glandular below. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 4 to 13 flowers. Pedicels (0.4-)0.7-1.4(-2.0)cm long, sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, or only with multicellular gland-tipped hairs, rarely with multicellular eglandular and gland-tipped hairs or with unicellular and multicellular eglandular hairs. Sepals less than 0.1-0.3(-1.0)cm long, often varying in length on die same flower; margins glandular-fimbriate, occasionally setose or with both gland-tipped and eglandular multicellular hairs; abaxial surface sparsely to densely covered with unicellular and multicellular gland-tipped hairs or with only multicellular gland-tipped hairs, occasionally with unicellular and multicellular eglandular hairs, rarely with all three types of hairs or glabrous. Corolla white, or white and tinged with pink or lilac, occasionally yellowish, fragrance sweet, musky and heavy, the tube longer than the limb and gradually expanding into It; upper corolla lobe (0.8-)1.0-L8(-2.2) x (0.6-)0.7-1.2(-1.6)cm; lateral lobes (L0-)1.2-2.0(-2.4) x (0.4-)0.5-0.9(-1.3)cm; corolla tube (1.6-)1.9-2.6(-3.1)cm long, (0.1-)0.2-0.4(-0.5)cm wide at base; outer surface of corolla densely covered with unicellular and multicellular gland-tipped hairs, the gland-tipped hairs continuing in distinct Enes up the corolla lobes, occasionally lacking unicellular hairs; inner surface of corolla sparsely to densely covered with unicellular hairs or glabrous. Stamens (3.2-)4.1-5.4(-6.3)cm long, with dense terete or flattened unicellular hairs on proximal (1.8-)2.4-3.3(-3.8)cm of filament, exserted (3.0-)4.2-5.1(-6.3)cm long, exserted (1.7-)2.4-3.8(-4.3)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.3-)0.6-1.7(-2.6)cm; stigma 0.1-0.2(-0.3)cm wide. Ovary 0.2-0.4(-0.6)cm long, 0. l-0.2(-0.3)cm wide at the base, sparsely to densely covered with multicellular gland-tipped hairs and unicellular hairs, occasionally with multicellular eglandular hairs and unicellular hairs, or eglandular, gland-tipped hairs, unicellular hairs, rarely with only multicellular gland-tipped hairs. Capsules (1.0-)1.2-1.8(-2.4) x 0.4-0.6(-0.8)cm, ovate to narrowly ovate, sparsely covered with unicellular hairs and moderately to densely covered with multicellular gland-tipped hairs, often glaucous. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (L2-)1.9-3.4(-3.5)x(0.6-1.0) expanded and dorsiventrally flattened surrounding the body, the cells elongate over the body of the seed, becoming shorter in the expanded portion of the testa, with transverse end-walls (Fig. 9).

Distribution

Delaware to south-eastern Georgia along the Atlantic Coastal Plain

Altitude

Habitat

Sandy pinelands, swamps, shrub bogs, or along streams. Femald (1942) cites this

        species as 'thoroughly distinctive'of the Coastal Plain.

Nomenclatural History

Azalea atlantica Ashe, Bull.Charles.Mus.l3:26(1917).TyPe:SouthCaroUna, Georgetown Co ï moist pine woods, Kinlock, 1 v 1916, W. W. Ashe s.n. (lecto., designated here, GH). Azalea atlantica Ashe var. luteo-alba Coker, J. Elisha Mitchell Sci. Soc. 36: 98, pi. 1 (1920). Rhododendron atlanticum (Ashe) Rehder var. luteo-album (Coker) Rehder, Monogr. Azaleas 150 (1921). R. atlanticum (Ashe) Rehder f. luteo-album (Coker) Fern. Rhodora 43: 622. (1941).Type: South Carolina, Darlington Co.: flatwoods, Hartsville, 4 iv 1918, /. L. Coker, Jr s.n. (lecto., designated here, NCU). Azalea neglecta Ashe, Bull. Torrey Bot. Club 47: 581 (1920). Rhododendron neglectum (Ashe) Ashe, Rhodora 23: 179 (1921). R. atlanticum (Ashe) Rehder f. neglectum (Ashe) Rehder, Monogr. Azaleas, 149-150 (1921). Type: South Carolina, Darlington Co.: moist pine woods, Kinlock, Georgetown, 1 v 1916, W. W. Ashe s.n. (holo. GH). Rhododendron atlanticum (Ashe) Rehder f. confusumVzm., Rhodora43: 622 (1941). Type: Virginia, Princess Anne Co.: dry oak thicket, Virginia Beach, 4 v 1935, Fernald & Griscom 4479 (holo. GH). Rhododendron atlanticum (Ashe) Rehder f. tom6>/o&wmFern.,Rhodora43:622 (1941). Type: Virginia, Nansemond Co.: a considerable colony, 6-9dm high, in dry white sand of pineland, south west of Marsh Hill School, south of South Quay, 10 v 1940, Fernald & Long 11881 (holo. GH; iso. GH, NY, PH).

Notes

References

Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):290