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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

MADIA TARWEED, TARPLANT

Bruce G. Baldwin


Annual, 0.5–25 dm. Stem: erect. Leaf: proximal opposite, often in rosettes, distal alternate, sessile; blades lanceolate or oblong-linear to linear, generally entire, seldom toothed, coarse- to soft-hairy, generally also glandular. Inflorescence: heads generally radiate, occasionally obscurely so (discoid), in flat-topped or panicle-, raceme-, or spike-like clusters; involucre 1–10+ mm diam, generally ± spheric to ovoid or urn-shaped; phyllaries in 1 series, lance-linear to oblanceolate, each mostly or wholly enfolding a subtended ray ovary, falling with fruit, coarse-hairy, generally glandular; receptacle flat to convex, glabrous or minutely bristly; paleae in 1 series between ray and disk flowers, ± fused or free, phyllary-like but more scarious, generally persistent (falling readily in Madia radiata). Ray flower: (0)1–22; corolla generally ± yellow, ray sometimes maroon or ± purple adaxially, proximally, or throughout. Disk flower: 1–80+, bisexual or staminate; corolla generally ± yellow, sometimes ± purple, tube <= throat, lobes deltate; anther ± dark purple or yellow to ± brown, tip oblong to ± ovate or ± semicircular; style glabrous proximal to branches, tips narrowly triangular, hairy. Fruit: ray fruit generally compressed side-to-side, generally ± 3-angled (rarely cylindric), ± club-shaped, often arched, glabrous, tip occasionally beaked, pappus 0; disk fruit 0 or similar to ray fruit, sometimes obovoid, often ± straight, tip not beaked, pappus 0.
10 species: western North America, southern South America; introduced elsewhere. (Native Chilean name) [Baldwin & Strother 2006 FNANM 21:303–308] Generally self-fertile (except Madia elegans and Madia radiata). Other taxa in TJM (1993) moved to Anisocarpus, Harmonia, Hemizonella, Jensia, Kyhosia.
Unabridged disk flower: anther base acute to cordate or sagittate.
Unabridged references: [Carlquist et al. 2003 Tarweeds and silverswords: evolution of the Madiinae (Asteraceae)]

Key to Madia

1. Paleae readily falling; ray fruit beaked, beak adaxially offset, curved; ray 6–19 mm; anthers yellow to ± brown ..... M. radiata

1' Paleae mostly persistent; ray fruit generally beakless or beak indistinct (if beaked, then ray <= 1 mm); ray 0.7–20 mm or rays 0; anthers ± dark purple or yellow to ± brown

2. Heads showy or not; disk flowers staminate, fruit 0, ovary wall remaining pale, membranous

3. Ray green-yellow, 4–11 mm; anthers ± dark purple; ray fruit ± widely 3-angled, abaxially broadly rounded, adaxially 2-faced, angles between those faces ± 70°, faces glossy ..... M. citriodora

3' Ray bright yellow, often maroon at base, 4–20 mm; anthers yellow to ± brown or ± dark purple; ray fruit compressed, abaxially slightly rounded, adaxially 2-faced, angles between those faces 15–45°, faces dull or glossy ..... M. elegans

2' Heads not showy; disk flower bisexual, forming fruit, ovary wall becoming dark, rigid

4. Heads generally tightly grouped, occasionally in flat-topped or panicle-like clusters; involucre narrowly ovoid or ellipsoid; ray flowers 0 or 1–3 ..... M. glomerata

4' Heads in crowded or open, flat-topped, panicle-, raceme-, or spike-like clusters; involucre ± spheric, (ob)ovoid, or urn-shaped; ray flowers (1)3–13(14)

5. Anthers yellow to ± brown; stem 1–30(60) cm; phyllary glands ± yellow; phyllary tips ± erect, often grooved along midvein

6. Heads in open, flat-topped or raceme- or panicle-like clusters; peduncle ± thread-like; involucre 2.5–5 mm, depressed-spheric; disk flowers 1(2), corolla glabrous; ray fruit black or brown, beaked, beak adaxially offset, curved ..... M. exigua

6' Heads in narrow raceme- or spike-like clusters; peduncle 0 or length generally < 2 × head; involucre 6–8 mm, spheric or ovoid; disk flowers 5–15, corolla hairy; ray fruit occasionally purple-mottled, beak 0 ..... M. subspicata

5' Anthers ± dark purple; stem (0.3)6–100(240) cm; phyllary glands black, purple, or yellow; phyllary tips erect or reflexed, flat

7. Ray fruit black or purple, round in ×-section, glossy ..... M. anomala

7' Ray fruit black, brown, purple, or mottled, compressed, dull or glossy

8. Stem glandular-hairy throughout; heads in raceme-, panicle-, or spike-like clusters; involucre 6–16 mm; often coastal ..... M. sativa

8' Stem distally glandular-hairy; heads in flat-topped, raceme-, or panicle-like clusters; involucre 5–10 mm; mostly away from immediate coast

9. Lateral branches often exceeding main stem in large plants; ray 6–8 mm ..... M. citrigracilis

9' Lateral branches seldom exceeding main stem; ray 1.5–8 mm ..... M. gracilis

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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