Sag. Stor. Nat. Chili, 136, 354. 1782.
Annuals, 5–250 cm. Stems erect. Leaves mostly cauline (at flowering) proximal opposite (often in rosettes), distal alternate; sessile; blades lanceolate or oblong-linear to linear, margins usually entire, sometimes toothed, faces hirsute to strigose, usually glandular-pubescent as well. Heads usually radiate (sometimes discoid in M. glomerata), in corymbiform, paniculiform, racemiform, or spiciform arrays or in glomerules. Peduncular bracts: pit-glands, tack-glands, and/or spines 0. Involucres ellipsoid, depressed-globose, globose, obconic, ovoid, or urceolate, 1–10+ mm diam. Phyllaries 0 (then outer paleae functioning as phyllaries, sometimes in M. glomerata), or 1–22 in 1 series (lance-linear to lance-attenuate or oblanceolate, herbaceous, each mostly or wholly enveloping a subtended ray ovary, abaxially hirsute and, usually, glandular). Receptacles flat to convex, glabrous or setulose, paleate (paleae persistent or falling readily, in 1 series between rays and discs, ± connate or distinct, phyllary-like, more scarious). Ray florets 0 (sometimes in M. glomerata), or 1–22, pistillate, fertile; corollas yellowish (with maroon bases sometimes in M. elegans; purplish red sometimes in M. sativa). Disc florets 1–80+, bisexual and fertile or functionally staminate; corollas usually yellow, sometimes purplish, tubes shorter than or about equaling funnelform throats, lobes 5, deltate (anthers ± dark purple or yellow to brownish; styles glabrous proximal to branches). Ray cypselae compressed, ± 3-angled, or rarely terete, clavate (often arcuate, basal attachments central or offset, apices sometimes beaked, faces glabrous); pappi 0. Disc cypselae similar, sometimes obovoid (often ± straight, basal attachments central, apices not beaked), sometimes 0; pappi 0. x = 8.
North America, South America, Pacific Islands (Hawaii, probably introduced).
Species 10 (10 in the flora).
Madia is more narrowly circumscribed here than in previous treatments by D. D. Keck (1959) and others. Molecular phylogenetic data have indicated that Madia in those earlier senses is not monophyletic (B. G. Baldwin 1996). As treated here, Madia comprises all members of Keck’s informal “section Madia” except M. minima (= Hemizonella) (Baldwin 1999b). Most species are reportedly either cross-incompatible or intersterile (J. Clausen 1951).
|1||Ray laminae 6–19 mm; paleae readily falling; anthers yellow to brownish; ray cypselae beaked (beaks adaxially offset, curved)||Madia radiata|
|1||Ray laminae 0.7–20 mm (rays sometimes 0 in M. glomerata); paleae mostly persistent; anthers yellow to brownish or ± dark purple; ray cypselae sometimes beaked.||> 2|
|2||Plants self-incompatible (heads showy) or self-compatible (heads not showy); disc florets functionally staminate (cypselae 0, ovary walls remaining pallid, membranous)||> 3|
|2||Plants self-compatible (heads not showy); disc florets bisexual (forming cypselae, ovary walls becoming dark, rigid)||> 4|
|3||Ray laminae greenish yellow, 4–11 mm; anthers ± dark purple; ray cypselae ± 3-angled (abaxial sides broadly rounded, adaxial sides 2-faced, angles between those faces ca.70°), glossy||Madia citriodora|
|3||Ray laminae bright yellow (sometimes with maroon bases), 4–20 mm; anthers yellow to brownish or ± dark purple; ray cypselae compressed (abaxial sides slightly rounded, adaxial sides 2-faced, angles between those faces 15–45°), dull or glossy||Madia elegans|
|4||Heads usually in glomerules, sometimes in corymbiform or paniculiform arrays; involucres narrowly ovoid or ellipsoid; ray florets 0 or 1–3||Madia glomerata|
|4||Heads in crowded or open, corymbiform, paniculiform, racemiform, or spiciform arrays; involucres depressed-globose, globose, obovoid, ovoid, or urceolate; ray florets (1–)3–13(–14)||> 5|
|5||Stems 1–30(–60) cm; phyllaries glandular-pubescent (glands golden yellow), apices ± erect, often sulcate; anthers yellow to brownish||> 6|
|5||Stems 10–200 cm; phyllaries glandular-pubescent (glands black, purple, or yellow), apices ± reflexed, flat; anthers ± dark purple||> 7|
|6||Heads in ± spiciform arrays; involucres globose or ovoid, 6–8 mm; disc florets5–15, corollas pubescent; ray cypselae sometimes purple-mottled, beakless||Madia subspicata|
|6||Heads in racemiform or paniculiform arrays (peduncles filiform); involucres depressed-globose, 3–5 mm; disc florets 1(–2), corollas glabrous; ray cypselae black, beaked (beaks adaxially offset, curved)||Madia exigua|
|7||Ray cypselae black or purple, terete, glossy||Madia anomala|
|7||Ray cypselae black, purple, or mottled, compressed, dull or glossy||> 8|
|8||Stems glandular-pubescent throughout; heads in racemiform, paniculiform, or spiciform arrays; involucres 6–16 mm; mostly coastal||Madia sativa|
|8||Stems distally glandular-pubescent; heads in corymbiform, racemiform, or paniculiform arrays; involucres 5–10 mm; mostly away from immediate coast||> 9|
|9||Lateral branches often surpassing main stems (in large plants); ray laminae 6–8 mm||Madia citrigracilis|
|9||Lateral branches seldom surpassing main stems; ray laminae 1.5–8 mm||Madia gracilis|