Solidago ouachitensis

Plants 60-110 cm; caudices woody. Stems 1-3+ , erect, straight, glabrous proximally to sparsely hairy in arrays. Leaves: basal withering by flowering; proximal cauline sessile, blades elliptic, 100-130 × 35-45 mm, margins sharply serrate (with 20-31 teeth), abaxial faces glabrous, adaxial glabrous or sparsely hairy; distal cauline sessile, blades narrowly elliptic, 65-80 × 13-24 mm, bases cuneate, margins entire to slightly serrate, apices acuminate, faces glabrous. Heads 25-50, in non-secund, short, axillary and terminal racemiform/paniculiform arrays 13-25 cm. Peduncles 0.5-3 mm, sparsely hispido-strigose; bracteoles ovate, 1-3 near each head, grading into phyllaries. Involucres narrowly campanulate, (6.5-)7-8 mm. Phyllaries in ca. 3-4 series, unequal, 1-nerved, obtuse; outermost linear-oblong, 0.8-1.3 mm. Ray florets 1; laminae 2.4-4.7 × ca. 1 mm. Disc florets 4-5; corollas 1.8-2.8 mm, lobes 0.8-1.6 mm. Cypselae 1.5-2.7 mm, glabrous; pappi 3-3.5 mm. 2n = 18.

Flowering Sep-Oct. Woods of north facing slopes; of conservation concern; 500-700 m; Ark., Okla.

Historically Solidago ouachitensis has been included in S. caesia or S. curtisii; it is ecologically and morphologically distinct.

Solidago ouachitensis is known only from the mesic, north-facing slopes of the Ouachita Mountains along the border of Arkansas and Oklahoma. It is a very infrequent species deserving protection and is in the Center for Plant Conservation´s National Collection of Endangered Plants.