What’s a dichotomous key?
Help
Dysphania
See list of 7 species in this genusFormerly included in Chenopodium, the genus Dysphania is considered to be generically distinct on the basis of indument. References: Wahl (1954), Clemants and Mosyakin (2003).
-
1a. Calyx connate except at the very apex, prominently reticulate-veiny, completely enclosing the mature fruit [Fig. 337]; leaves not aromatic, the blades lacking glands
-
1b. Calyx distinct or connate only at base, not reticulate-veiny, enclosing the fruit or not at maturity; leaves aromatic, the blades with either resin glands or glandular hairs (very rarely lacking both)
-
2a. Fruits mostly vertically oriented in the calyx, oval in outline, 0.5–0.7 mm wide
-
3a. Sepals with a fimbriate keel on the abaxial (i.e., outer) surface; glomerules of flowers 4–6 mm wide
-
3b. Sepals lacking a keel on the abaxial surface; glomerules of flowers 1.2–2.8 (–3.5) mm wide
-
-
2b. Fruits mostly horizontally oriented in the calyx, suborbicular or oval in outline, 0.6–1 mm wide
-
4a. Leaf blades 1.3–4.5 cm long, the lower typically pinnately lobed; pericarp of fruit often with translucent white strips or blotches, lacking glands, firmly adherent to seed; gynoecium with 2 stigmas; flowers mostly solitary, many with pedicels
-
5a. Sepals acute to acuminate at the apex, glandular-pubescent, lacking tubercles; cymes densely arranged on raceme-like branches
-
5b. Sepals acute to obtuse, with sessile glands, with a single tubercle on the abaxial surface; cymes diffusely arranged on raceme- to panicle-like branches
-
-
4b. Larger leaf blades (2–) 4.5–8 (–12) cm long, serrate to laciniately toothed; pericarp of fruits lacking translucent white marks, glandular, not adherent to seed and separating at maturity; gynoecium with 3 stigmas; flowers in small glomerules, sessile
-
6a. Glomerules of flowers subtended by obvious bracts; lower leaf blades typically serrate; plants flowering in summer through fall
-
6b. Glomerules of flowers lacking bracts throughout or with very small bracts shorter than the glomerules [Fig. 336]; lower leaf blades typically laciniately serrate; plants flowering in late summer through fall
-
-
-
Show photos of:
Each photo represents one species in this genus.