Flora of North America species comparison

1–10+, ascending to erect, freely branched, glabrous or sparsely pubescent.

deciduous, basal and cauline (basal usually withering before or at flowering);

stipules persistent, adnate to petiole, those of basal leaves simple, lanceolate, entire, of cauline pectinately divided;

petiole present;

blade oblanceolate to obovate, 2–7 cm, herbaceous, leaflets 3–8 pairs, proximally alternate, subopposite, or opposite, distally subopposite or opposite, broadly elliptic to obovate, margins flat, pectinately pinnatisect (segment margins nearly parallel), faces glabrous.

terminal, also often axillary to distal leaves, 12–100+-flowered, headlike spikes, cylindric, or subglobose when poorly developed, glabrous or nearly so;

peduncles present, sometimes absent;

bracts absent;

bracteoles present.

absent.

1–3 mm diam.;

hypanthium urceolate, compressed at mouth, 1–3 mm, glabrous;

sepals 4, ascending to spreading, ovate, margins scarious;

petals 0;

stamens 2 (and opposite inner sepals) or 4, equal to sepals;

carpel 1, glabrous, styles repeatedly branched, brushlike.

(2 or)4.

hypanthia ridges extended into thin wings, 0.5 mm wide;

sepals tuberculose-thickened proximally.

achenes, 1, globose, 1.5–2 mm diam., glabrous;

hypanthium persistent, enclosing achenes;

sepals persistent, ascending to spreading.

= 7.