Stem very slender, erect, up to over 3 ft. high, obtusely quadrangular, sulcate, sparingly pubescent or glabrescent, with very few sessile glands among the hairs. Leaves subsessile, linear, entire, acute, subcuneate at the base, up to 3 in. long, 3/4–2 lin. broad, sparingly and minutely pubescent and whitish-glaucous from sessile glands, at length glabrescent above, nerves distinct, about 5 on each side, very oblique, veins distinct except in the narrowest leaves. Pedicels in flower 4–1 (at length 2) lin. long, minutely 2-bracteolate; nectaries subsessile. Calyx 2 lin. long, whitish glaucous or grey, minutely pubescent; segments linear-lanceolate, acuminate. Corolla pale rose-colour, obliquely campanulate, about 1 1/4 in. long, finely pubescent; lowest lobe broad-ovate, rounded, 3 lin. long and broad. Capsule shortly rostrate, 7–8 lin. long, 2 lin. broad, obtusely quadrangular, 4-sulcate; beak 1 lin. long, rather broad and often obtuse. Seeds 1 lin. long, margins very acute, faces faintly rugose, sides broad, transversely rugulose.
