General: Perennial herb from a stout taproot and branched stem-base with fibrous roots; stems erect, solitary, simple, usually smooth, 10-120 cm tall.
Leaves: Basal leaves linear to egg-shaped, long-stalked, 7-40 cm long, 0.7-5 cm wide, simple or sometimes lobed; stem leaves opposite, 2-6 pairs, pinnately cleft with narrow segments, becoming unstalked, terminal lobe linear to narrowly lanceolate.
Flowers: Inflorescence a compact panicle of either male, female or both female and male flowers; female flowers 1 mm long and male or male/female flowers 2.5-3.5 mm long; corollas white, either about 1 mm long (female) or 2.5-3.5 mm long (male), lobed, the lobes slightly shorter than the tubes; calyces with mostly 9-13 feathery segments; stamens only slightly exserted.
Fruits: Achenes, egg-shaped, 2.5-4.5 mm long, short-hairy or nearly smooth.
If more than one illustration is
available for a species (e.g., separate illustrations were provided for two
subspecies) then links to the separate images will be provided below.
Note that individual subspecies or varietal illustrations are not always available.
