Flora of North America species comparison

erect or decumbent, usually branched proximally and distally, glabrous or minutely pubescent.

usually prostrate to erect, sometimes scandent, not scapose, rarely with recurved spines (some species of Persicaria), glabrous or pubescent, sometimes glandular;

nodes usually swollen;

branches free (adnate to stems distal to nodes and appearing to arise internodally in Polygonella);

tendrils absent (except in Antigonon and Brunnichia).

persistent;

ocrea margins not ciliate;

blade linear to narrowly clavate or broadly spatulate, (3–)4–16(–36) × (0.3–)0.6–3.6(–5) mm, base barely tapered to attenuate, margins hyaline at least along distal 1/2, apex obtuse, glabrous.

deciduous (persistent in Coccoloba and sometimes more than 1 year in Antigonon and Polygonella), basal or basal and cauline, rarely cauline only, mostly alternate;

ocrea present, persistent or deciduous, cylindric to funnelform, chartaceous, membranous, coriaceous, or, rarely, foliaceous or partly so;

petiole present or absent, rarely articulate basally (Fagopyrum, Fallopia, Polygonella, Polygonum), rarely with extrafloral nectaries (Fallopia, Muehlenbeckia);

blade simple with entire margins, rarely undulate or lobed.

(2–)4–20(–33) mm;

ocreola encircling rachis, only the base adnate to rachis, apex acute to acuminate.

terminal or terminal and axillary, spikelike, racemelike, paniclelike, cymelike, or, rarely, capitate, comprising simple or branched clusters of compound inflorescences;

bracts absent;

peduncle spreading to erect, sometimes absent;

clusters of flowers subtended by connate bracteoles forming persistent membranous tube (ocreola), awnless.

spreading in anthesis, spreading to reflexed in fruit, 0.2–0.9 mm, as long or much longer than subtending ocreola.

functionally unisexual;

filaments dimorphic;

anthers pink, orange, or yellow;

styles and stigma ca. 0.1 mm in anthesis.

usually bisexual, sometimes bisexual and unisexual on same plant, rarely unisexual only, 1–20+ per ocreate fascicle, often with stipelike base distal to articulation;

perianth often accrescent in fruit, often greenish, white, pink, yellow, red, or purple, usually unwinged and unkeeled (winged or, sometimes, keeled in Fallopia, rarely keeled in Polygonum), campanulate or urceolate, sometimes membranous, indurate, or fleshy in fruit, rarely developing raised tubercles proximally (Rumex), glabrous or pubescent, sometimes glandular or glandular-punctate;

tepals 2–6, usually in 2 whorls, distinct or connate proximally and forming tube, petaloid or sepaloid, monomorphic or dimorphic;

nectary a disk at base of ovary or glands associated with bases of filaments;

stamens usually (1–)6–9, staminodes rarely present;

filaments distinct, or connate basally and sometimes forming staminal tube, free or adnate to perianth tube;

pistils (2–)3(–4)-carpellate;

ovary 1-locular (sometimes with vestigial partitions proximally);

ovule 1, orthotropous or, rarely, anatropous, placentation basal or free-central;

styles 1–3, erect to spreading or recurved, distinct or connate proximally;

stigmas peltate, capitate, fimbriate, or penicillate.

outer tepals loosely appressed in anthesis, reflexed in fruit, white, broadly elliptic, 0.9–1.8 mm in anthesis, margins entire;

inner tepals appressed in anthesis and fruit, white, elliptic, 0.9–1.7 mm in anthesis, margins entire.

outer tepals loosely appressed in anthesis, usually reflexed in fruit, white to pink, often drying yellow, broadly elliptic to ovate, 0.5–1.3 mm in anthesis, margins entire;

inner tepals appressed in anthesis and fruit, white to pink, often drying yellow or red, broadly elliptic to ovate, 0.6–1.5 mm in anthesis, margins entire.

mostly included, brown to yellow-brown, 3-gonous, 1.3–2.1 × 0.7–1.2 mm, shiny, smooth.

yellowish, brown, red, or black, homocarpic (sometimes heterocarpic in Polygonum), winged or unwinged, usually 2–3-gonous, sometimes discoid, biconvex, or spheroidal, rarely 4-gonous.

embryo usually straight or curved, rarely folded.

= 28.