Flora of North America species comparison

retrorsely hairy or puberulent, sometimes glandular-pubescent distally or glabrescent, not glaucous.

prostrate, decumbent, ascending, or erect, sometimes arching, creeping, sprawling, spreading, scrambling, pendent, climbing, or reclining, sometimes absent.

basal and cauline, basal usually absent at anthesis, opposite, leathery or not, glabrous, puberulent, or retrorsely hairy, not glaucous;

basal and proximal cauline petiolate, sometimes short-petiolate or sessile (P. dasyphyllus);

cauline sessile, sometimes short-petiolate (P. lanceolatus), blade lanceolate or linear, margins entire.

deciduous or persistent, basal, basal and cauline, or cauline, opposite, subopposite, alternate, helical, or whorled, sometimes opposite proximally, alternate distally, simple;

stipules absent;

petiole present or absent;

blade fleshy or not, leathery or not, margins entire to subentire, toothed, or lobed.

interrupted, ± secund to cylindric, axis glandular-pubescent or glabrous, cymes 1 or 2 per node;

peduncles and pedicels ascending to erect.

axillary or terminal, spikes, racemes, cymes, corymbs, thyrses, whorls, panicles, spiciform, or flowers 1–4.

calyx lobes: margins entire or erose (P. stenophyllus), herbaceous or narrowly scarious, sometimes broadly scarious (P. stenophyllus), glandular-pubescent or glabrous;

corolla lavender to blue, violet, purple, red, or scarlet, bilaterally symmetric, bilabiate, not personate, ventricose or tubular-funnelform, glandular-pubescent externally, glabrous or glandular-pubescent internally abaxially, throat abruptly or gradually inflated, not constricted at orifice, rounded to 2-ridged abaxially;

stamens included to exserted, filaments glabrous, pollen sacs parallel to divergent, navicular to slightly saccate, dehiscing completely or incompletely, distal 1/5 or less sometimes indehiscent, connective splitting, sides glabrous, sutures denticulate, teeth to 0.2–0.3 mm;

staminode included or exserted, flattened distally, 0.3–2.6 mm diam., tip recurved, glabrous;

style glabrous.

bisexual, rarely unisexual (Callitriche, Hippuris, Littorella), perianth and androecium hypogynous (epigynous in Hippuris);

sepals (2–)4 or 5, basally or proximally connate, sometimes distinct, rarely a minute rim (Hippuris) or 0 (Callitriche), calyx radially or bilaterally symmetric;

petals 0 (Callitriche, Hippuris) or (3 or)4 or 5, connate, corolla radially or bilaterally symmetric, ± bilabiate, bilabiate and personate, or regular, rarely unilabiate (Synthyris), ± rotate to salverform, ± cylindric, tubular, funnelform, urceolate, ellipsoid, globular, ovoid, or ligulate;

stamens (1 or)2–4 or 5, adnate to corolla or free, didynamous or equal, staminodes 0 or 1(–3);

pistil 1, 2-carpellate (1 in Hippuris), ovary superior (inferior in Hippuris), 2-locular, sometimes 1-locular or 4-locular (Callitriche), placentation axile, sometimes parietal (Dopatrium), parietal centrally and axile distally and proximally (Synthyris), apical (Hippuris), basal (Callitriche, Littorella), or free-central (Plantago);

ovules anatropous, hemitropous, hemianatropous, or campylotropous, unitegmic, tenuinucellate;

styles [0]1 (2 in Callitriche);

stigma 1 (2 in Callitriche).

capsules, dehiscence loculicidal, septicidal, or poricidal, or nutlets (Littorella), pyxides (Plantago), schizocarps (Callitriche), drupes (Hippuris), or drupelike (Lagotis).

glabrous.

brown to dark brown, angled, 1.9–3.2 mm.

1–300, white, tan, brown, yellow, gray, black, maroon, or red, ovoid to ellipsoid, cylindric, globular, oblong, conic, disciform, patelliform, or angled;

embryo straight, rarely curved, endosperm present.