Rhododendron flammeum (Michx.) Sargent

Rhodo. Soc. Notes 1: 120 (1917)

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Description

Shrub or small tree to 2.5m tall, usually non-rhizomatous; young twigs

        red-brown, densely covered with unicellular and multicellular eglandular hairs.

        Vegetative bud scales glabrous, to densely covered with unicellular hairs abaxially;

        margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic,

        (2.9-)3.9-6.3(-8.2) x (1.3-)1.5-2.4(-2.7)cm; base acute to oblique; apex acute to

        obtuse, often mucronate; adaxial surface glabrous or sparsely covered with multicellular

        eglandular hairs or with unicellular hairs, the midvein densely covered with unicellular

        hairs; abaxial surface densely covered with unicellular or multicellular eglandular

        hairs, or with both, or glabrous, the midveie sparsely to densely covered with

        unicellular hairs and multicellular eglandular hairs; margin entire, ciliate with

        multicellular eglandular hairs; petiole Q.2-0.6cm long, sparsely to densely covered with

        unicellular and multicellular eglandular hairs. Flower bud scales chestnut brown;

        abaxial surface sparsely to densely covered with unicellular hairs, rarely completely

        glabrous; margin unicellular-ciliate. Flowers appearing before or with the leaves', inflorescence a shortened raceme of 6 to 11 flowers. Pedicels (0.3-)0.5-0.9(-1.0)cm long, sparsely to densely covered with unicellular and multicellular eglandular hairs. Sepals less than 0.1-0.3(-0.5)cm long, often varying in length on the same flower; margins setose with multicellular eglandular hairs; abaxial surface sparsely covered with unicellular and multicellular eglandular hairs. Corolla scarlet, reddish orange to orange, fragrance acrid, the tube longer than the limb and abruptly expanding into it; upper corolla lobe 0.8-1.7(-2.2) x(0.7-)0.8-1.6(-1.9)cm wide; lateral lobes (1.0-)1.1-1.8(-2.1) x (0.5-)0.6-1.0(-U)cm; corolla tube (1.7-)1.8-2.3 (-2.5)cm long, 0.2-0.3(-0.4)cm wide at base; outer surface of corolla sparsely covered with unicellular and multicellular eglandular hairs, the multicellular hairs continuing up the corolla lobes, rarely with unicellular and multicellular gland-tipped hairs (glands of hairs minute, poorly developed); inner surface of corolla densely covered with unicellular hairs. Stamens (4.0-)4.3-6.3(-7.3)cm long, with dense terete or flattened unicellular hairs on proximal (2.0-)2.1-2.8 (-3.3)cm of filament, exserted (2.4-)2.5-3.9(-5.0)cm beyond throat of corolla. Style (4.5-)4.9-6.8(-7.4)cm long, exserted (3. l-)3.3-5.0(-5.4)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.1-1.4(-2.2)cm; stigma 0.1-0.2(-0.4)cm wide. Ovary 0.3-0.4(-0.5)cm long, 0.1-0.2(-0.3)cm wide at the base, densely covered with multicellular eglandular hairs over unicellular hairs. Capsules L5-2.3(-2.6) x 0.5-0.7(-0.8)cm, ovate, sparsely covered with unicellular hairs and moderately to densely covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.8-)2.0-2.7(-2.8) x 0.7-1.l(-1.2)mm, body 0.9-1.3 x 0.4-0.7(-0.8)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate over the body of the seed, short in the expanded portion of the testa, with transverse end-walls (Fig. 5). Chromosome number: In = 26 (Li, 1957). Figure 31; see additional illustrations in Prince, 1978 (photo) and Galle, 1985 (photo).

Distribution

USA: Georgia and South Carolina

Altitude

Habitat

Upland woods, dry slopes and ridges, bluffs of rivers or stream banks, sandhills

Nomenclatural History

Azalea calendulacea Michx. Nm.flammea Michx., Fl. Bor.-Amer. 1: 151 (1803). Type: Georgia: Savannah River, Two Sisters Ferry. 26-27 iv 1787, A Michaux s.n. (lecto. P-MICHX; photo of holo. A). Azalea nudiflora var. coccinea Aiton, Hort. Kew. 1: 202 (1787). A. periclymenoides var. coccinea (Aiton) Pursh, Fl. Am. Septentr. 1: 152 (1814). Rhododendron nudiflorum var. coccineum (Aiton) Sweet, Hort. Brit. ed. 2, 343 (1830). Type: n.v.

Notes

References

Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):311