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FNA | Family List | FNA Vol. 21 | Asteraceae

256. Melampodium Linnaeus, Sp. Pl. 2: 921. 1753; Gen. Pl. ed. 5, 392. 1754.

[Often said (erroneously) to be from Greek melampodion, blackfoot; evidently traceable to Melampus, a soothsayer of renown in Greek mythology]

John L. Strother

Annuals, perennials, or subshrubs, 5–50(–150+) cm. Stems erect or prostrate. Leaves cauline; opposite; petiolate (petioles usually winged) or sessile; blades deltate, lance-elliptic, lanceolate, lance-linear, linear, linear-oblong, ovate, or rhombic, sometimes pinnately lobed, ultimate margins entire or toothed, faces usually hairy, usually gland-dotted (at least abaxial). Heads radiate, borne singly (from forks of branches, peduncles often uncinate). Involucres mostly hemispheric (sometimes ± cupulate), [4–]5–20(–30+) mm diam. Phyllaries persistent (outer) or falling with cypselae, 8–20+ in 2 series (outer [2–]5 often ± connate, herbaceous, inner each investing a ray ovary, forming a perigynium, shed with enclosed cypsela). Receptacles flat or convex to conic (their tips, paleae, and spent florets often shed as a unit), paleate (paleae lanceolate to linear, scarious, conduplicate, often with dilated, erose tips). Ray florets [3–]5–13+, pistillate, fertile; corollas yellow, orange, or cream-white, sometimes purplish abaxially (tubes often wanting). Disc florets [3–]45–70[–100+], functionally staminate; corollas ochroleucous, yellow, or orange, tubes shorter than funnelform throats, lobes 5, ± deltate. Cypselae each enclosed within and shed with a smooth, sculpted, or tuberculate, scarious, coriaceous, or hardened perigynium (the ultimate "fruits" ± compressed, ± D-shaped); pappi 0. x = 12.

Species ca. 36 (7 in the flora): United States, Mexico, West Indies, Central America, South America; introduced in Old World.

SELECTED REFERENCE

Stuessy, T. F. 1972. Revision of the genus Melampodium (Compositae: Heliantheae). Rhodora 74: 1–70, 161–219.


1 Perennials; ray corollas cream-white   (2)
+ Annuals; ray corollas yellow to yellow-orange   (3)
       
2 (1) Outer phyllaries connate 1/2–3/5 their lengths; ray laminae 7–13 × 2.5–8 mm   1 Melampodium leucanthum
+ Outer phyllaries connate 1/6–1/3+ their lengths; ray laminae 2–8+ × 1–3+ mm   2 Melampodium cinereum
       
3 (1) Leaf blades deltate or rhombic to lanceolate, lengths 1–2(–3) times widths   (4)
+ Leaf blades lance-elliptic or oblanceolate to linear, lengths (3–)4–8+ times widths   (5)
       
4 (3) Outer phyllaries ovate, 3.5–6 mm, connate 1/4–1/3 their lengths; disc florets 40–70+; fruits 2.8–4 mm   3 Melampodium divaricatum
+ Outer phyllaries oblong-elliptic, (6–)8–15+ mm, connate 0–1/6 their lengths; disc florets 30–45; fruits 4–7 mm   4 Melampodium perfoliatum
       
5 (3) Outer phyllaries connate 3/5–2/3 their lengths; disc florets 25–40   5 Melampodium appendiculatum
+ Outer phyllaries connate 0–1/6 their lengths; disc florets 4–10   (6)
       
6 (5) Peduncles 4–30+ mm; rays 7–12, laminae 1.2–1.5 mm; disc florets 8–10   6 Melampodium longicorne
+ Peduncles 0–3(–12+) mm; rays 5–8, laminae 0.6–1.1 mm; disc florets 4–6   7 Melampodium strigosum

Lower Taxa


 

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