Flora of North America species comparison

erect.

erect to ± prostrate (repeatedly “forked”).

blades rhombic-ovate to obovate, (20–)40–120(–150+) mm, faces finely pilosulous, gland-dotted.

cauline; opposite; petiolate or ± sessile;

blades mostly elliptic to deltate, rhombic, or ovate, sometimes lyrate, ultimate margins entire or toothed, faces usually pilosulous to sericeous or scabrellous, sometimes glabrate or glabrescent, usually gland-dotted.

± hemispheric, 3–5 mm diam. (becoming ± rotate in fruit).

convex, paleate (paleae cuneate to spatulate, ± conduplicate or flattish, membranous).

5–8, pistillate, fertile;

corollas yellowish (tubes shorter than to equaling laminae, laminae ovate to elliptic or linear).

3–8(–12+), functionally staminate;

corollas yellowish, tubes shorter than funnelform or campanulate throats, lobes 5, deltate.

persistent (outer) or falling, 10–13 in 2 series (outer 4–6 herbaceous, inner 5–8 each investing a ray ovary, enlarging in fruit to form a perigynium, shed with enclosed cypsela).

± compressed, ± cuneate to obovate, 4–6+ mm, not notably ribbed, terminal spines 2, divergent, 3–4 mm, often 1 ± uncinate, prickles seldom notably uncinate, ± scattered.

radiate, 1(–3) in “forks” of branches (terminal, appearing axillary by sympodial growth).

each enclosed within and shed with an often hardened, ± prickly perigynium (the ultimate “fruits” plumply ellipsoid to fusiform, or ± compressed);

pappi 0 or rudimentary.

= 11.

= 22.