Stems branched, 40–62 cm; branches ascending, terete to +/- quadrangular, glabrous or sparsely scabridulous. Leaves spreading; blade narrowly linear, 12–28(–35) x 0.8–1.5 mm, fleshy, margins entire, often siliceous, adaxial surface with siliceous, sessile, dome-shaped hairs; axillary fascicles shorter than subtending leaves. Inflorescences racemes or panicles, flowers 1 or 2 per node; bracts longer than pedicels. Pedicels ascending, 5–9 mm, glabrous. Flowers: calyx elongate-campanulate, tube 4.5–6 mm, glabrous, lobes narrowly lanceolate, 2.7–7 mm; corolla pink, with 2 yellow lines and dark red spots in abaxial throat, 17–23 mm, throat pilose externally and glabrous within across bases and sinus of adaxial lobes, lobes spreading, 4–6 mm, glabrous externally; proximal anthers parallel to filaments, distal parallel or oblique to filaments, pollen sacs 3–3.2 mm; style included or exserted, 13–15 mm. Capsules obovoid to oblong, 10–12 mm. Seeds brown, 1–2 mm.
Phenology: Flowering Aug–Sep.
Habitat: Wet alkaline, saline meadows and marshes associated with springs and seeps.
Elevation: 800–1100 m.
N.Mex., Tex., Mexico (Coahuila).
Within the flora area, Agalinis calycina is known only from desert, alkaline-saline, wet meadows and marshes. It is most closely related to A. heterophylla, from which it differs by its narrowly linear leaves, longer pedicels, shorter corolla lobes, included to slightly exserted style, and larger seeds and capsules. In Texas, A. calycina is known only from Pecos County in the trans-Pecos region.