41. Zizia W.D.J. Koch (golden Alexanders)
perennial, glabrous (or minutely hairy or roughened at some of the nodes), with
clusters of slightly to moderately tuberous-thickened roots. Stems erect or
ascending, sometimes from spreading bases. Leaves alternate and usually also
basal (2 to few basal leaves usually present at flowering), the basal and lower
stem leaves long-petiolate, the median and upper leaves short-petiolate to
nearly sessile, the sheathing bases not or only slightly inflated. Leaf blades
ovate to more or less circular in outline, simple or 1–3 times
ternately lobed or compound, the margins glabrous, with a narrow, white border.
Inflorescences terminal and axillary, compound umbels, short- to long-stalked.
Involucre absent. Rays 10–18, more or less unequal in length. Involucel
of 3–9 bractlets, these shorter than the flower stalks, linear,
sometimes reduced and fused basally into a low, irregular crown. Flowers
11–19 (to numerous) in each umbellet, the central flower of each
umbellet sessile or with a stalk less than 0.5 mm long, the others with stalks
1–4 mm long. Sepals minute triangular scales. Petals obovate, narrowed
or tapered abruptly to a short, slender tip, bright yellow. Ovaries glabrous.
Fruits 2–4 mm long, ovate to oblong-ovate in outline, flattened
laterally, glabrous, the mericarps reddish brown, the 5 ribs tan to yellowish
brown, angled and often somewhat corky, but lacking wings. Four species, North
Zizia is frequently confused with Thaspium.
For further discussion, see the treatment of that genus.