Flora of North America species comparison

decumbent to ascending or erect, glabrous or glandular-hairy.

decumbent, ascending, or erect, simple, sometimes few-branched, (8–)15–60 cm, sparsely to densely glandular-puberulent or glandular-pubescent proximally, glandular-puberulent distally.

cauline (also basal and clustered in G. amphiantha), opposite, monomorphic (dimorphic in G. amphiantha);

petiole absent;

blade not fleshy, not leathery, margins entire or toothed, surfaces often glandular-punctate.

blade lanceolate-ovate to ovate or oblong, rarely linear-lanceolate in submersed forms, 5–28 × 4–15 mm, margins with (3–)5–10(–12) pairs of sharp teeth, apex acute, rarely obtuse, surfaces sparsely to densely glandular-puberulent.

axillary, flowers 1 or 2 per node;

bracts present.

present, sometimes short;

bracteoles present or absent, sepal-like.

slender, 10–23 mm, length 0.5–2 times bract, sparsely to densely glandular-puberulent;

bracteoles 2, 3.5–7 mm.

bisexual;

sepals 5, distinct or proximally connate, calyx ± bilaterally symmetric, campanulate, lobes (sepals when distinct) linear to lanceolate, obovate, or oblong;

corolla white, cream, or yellow, sometimes pinkish, tube yellowish, brownish, or purplish, often with dark veins, bilaterally symmetric, bilabiate, tubular, tube base not spurred or gibbous, lobes 5, abaxial 3, adaxial 2, nearly completely connate and appearing as 1 emarginate lobe, throat glabrous or pubescent;

stamens 2, medially adnate to corolla, filaments glabrous, pollen sacs perpendicular to filaments, connective dilated;

staminodes 0 or 2, minute;

ovary 2-locular, placentation axile;

stigma capitate or lamelliform.

sepals distinct, lanceolate to elliptic or ovate-lanceolate, 3–7 mm;

corolla 9–13 mm, tube yellowish brown, veins blue or lavender, limb white;

style 3–4 mm.

capsules, dehiscence septicidal, sometimes also loculicidal.

globular, 1–2.5 × 1–2.5 mm.

ca. 200, yellow to brown or black, oblong to obpyramidal or short-cylindric, wings absent.

0.3–0.4 mm.

= 16.