Gambelia Nutt., Proc. Acad. Nat. Sci. Philad. 4(1): 7 (1848), et sec. Nutt., Jour. Acad. Nat. Sci. Philad. ser. 2 1(2): 149 (1848).
Spreading or juncoid shrubs; stems homomorphic, erect or ascending, the branches rarely cirrhous. Leaves homomorphic, simple, entire, pinnately veined or with several main veins from base, the midrib terminated with small gland, petiolate, 3-verticillate, opposite or rarely alternate above; petioles not cirrhous. Flowers zygomorphic, oriented horizontally, solitary in leaf-axils, usually in clusters of 2-3 towards shoot-apices or in terminal bracteate racemes. Floral leaves or bracts not subtending additional branches. Pedicels not cirrhous. Calyx divided almost to base; lobes subequal, imbricate or sometimes valvate. Corolla with tube subcylindric, saccate abaxially at base; limb bilabiate, the lips subequal, the adaxial lip patent or reflexed, the abaxial lip somewhat exceeding adaxial, spreading to patent with basa1 palate partially occluding mouth of tube; lobes entire. Fertile stamens 4, didynamous, the anthers free, included or somewhat exserted, the connective not dilated above anther; staminode minute, without rudimentary anther. Style erect, simple; stigma linear, entire, positioned somewhat below or at leve1 of anthers of fertile stamens. Capsule ovoid to subglobose, somewhat oblique at base, the walls thick, the septum erect, straight; loculi subequal with abaxial loculus exceeding adaxial, each loculus many-seeded, dehiscing initially by subapical transverse split, becoming 1 irregularly dentate pore, extending 0.2-0.25 distance from apex to base. Seeds oblong-ovoid, bilaterally symmetrical, usually with conspicuous dorsi-ventral asymmetry, alveolate or cristate; hilum subbasal on dorsal face; dorsal face with longitudinal ridges; ventral face alveolate or cristate; periclinal wall of testa-cells tabular-convex, that of cells from interstices with median papilla or hair papilla; epicuticular waxes absent.
By Sutton (1988)