Flora of North America species comparison

often several from base, erect to decumbent, branched or unbranched, glandular-hispid and puberulent.

erect, decumbent, lax, spreading, creeping, trailing, floating, or submerged, young ones often 4-angled.

opposite, sessile or subsessile;

petiole 0–1 mm;

blade ovate-lanceolate to oblong or elliptic, 5–15[–20] × 2–7[–10] mm, base cuneate to rounded.

deciduous, usually opposite, sometimes alternate, subalternate, or whorled, simple, rarely dimorphic, emergent and submerged leaves dissimilar;

stipules usually absent;

sessile, subsessile, or petiolate;

blade membranous [leathery], venation brochidodromous, each marginal vein forming a series of loops, margins entire (except coarsely toothed in Trapa), trichomelike glands present in axil at petiole base.

leafy.

indeterminate or determinate, terminal or axillary, racemes, spikes, cymes, panicles, [thyrses], or flowers solitary;

bracts absent (except present in Cuphea aspera);

bracteoles present, paired on pedicels.

0–3 mm.

alternate, solitary, interpetiolar;

floral tube green abaxially, purple adaxially, 5.5–8(–9) × 2–2.5 mm, sparsely glandular-hispid;

base rounded, 0.5 mm;

inner surface glabrous proximally, villous distal to stamens;

epicalyx segments thick, not terminated by a bristle;

sepals equal;

petals (2–)6, oblanceolate or oblong, unequal, 4 abaxial ones pale purple and 4–4.7 × 2.5–2.8 mm, 2 adaxial ones purple [deep purple or with deep purple midvein] and 4 × 1.5–1.9 mm;

stamens 11, reaching or surpassing sinus of sepals.

bisexual [unisexual], actinomorphic or zygomorphic;

perianth and androecium usually perigynous (semi-epigynous to epigynous in Punica, perigynous to semi-epigynous in Trapa), mono-, di-, or tristylous;

floral tube or cup persistent, campanulate, turbinate, urceolate, cylindrical, or obconic, green (except red or yellow in some Cuphea and Punica), sometimes conspicuously ribbed;

sepals persistent, 4–8, valvate, usually deltate, sometimes subulate in Lythrum, alternating with segments of epicalyx or epicalyx absent;

petals usually caducous or deciduous, rarely persistent, 0–8, distinct, on interior margin of floral tube between sepals, crinkled, pinnately-veined;

nectary present as distinct organ, as nectariferous tissue in wall of ovary or floral tube, or absent;

stamens (1–)4–42[+], usually equal to or 2 times number of petals, usually in 2 whorls of unequal length, sometimes 1 whorl;

anthers versatile [or basifixed], introrse, 2-locular, longitudinally dehiscent;

pistil 1;

ovary usually superior (semi-inferior to inferior in Punica and Trapa), 2–6-locular (to 9 twisted locules in Punica);

placentation axile, placenta elongate or globose;

septa incomplete near ovary apex (reduced to thin threads in Cuphea);

style 1;

stigma 1, capitate to punctiform, dry (wet in Heimia, Lagerstroemia, and Punica);

ovules 1–1400, anatropous, bitegmic.

capsules, walls usually thin and dry (thick in Decodon, woody in Lagerstroemia), or leathery berries (Punica), or indurated, 2–4-horned drupes (Trapa), usually smooth (striate in Rotala), dehiscence loculicidal, septicidal, or septifragal, or indehiscent and splitting irregularly.

8–13(–20), suborbiculate in outline, 1.5–2 × 1.5–1.7 mm, margin rounded.

3–250(–1400), usually brown (wine in Punica) [black, red], narrowly obovoid to fusiform, oblong to pyramidal, obovoid-semiovoid, semiorbicular, suborbicular, or elliptic (in outline), usually dry, fleshy in Punica, winged or not;

endosperm not developed;

embryo straight, oily, cotyledons usually ± complanate, rarely rolled, often auriculate or cordate.

= 28, 32 (Bolivia), 34 (Paraguay).