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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
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ASTERACEAE

SUNFLOWER FAMILY

David J. Keil, Family Editor and author, except as specified

Annual to tree
Leaves basal or cauline, alternate to whorled, simple to compound
Inflorescence: 1° inflorescence a head, each resembling a flower, 1–many, generally arrayed in cymes, generally subtended by ± calyx-like involucre; flowers 1–many per head
Flowers bisexual, unisexual, or sterile, ± small, of several types; calyx 0 or modified into pappus of bristles, scales, or awns, which is generally persistent in fruit; corolla radial or bilateral (rarely 0), lobes generally (0)4–5; stamens 4–5, anthers generally fused into cylinder around style, often appendaged at tips, bases, or both, filaments generally free, generally attached to corolla near throat; pistil 1, ovary inferior, 1-chambered, 1-seeded, style 1, branches 2, generally hair-tufted at tip, stigmas 2, generally on inside of style branches
Fruit: achene, cylindric to ovoid, generally deciduous with pappus attached
Genera in family: ± 1300 genera, 21,000 species (largest family of dicots): worldwide. Largest family in CA. Also see tribal key to CA genera: Strother 1997 Madroño 44(1):1–28. See glossary p. 25 for illustrations of general family characteristics.

LACTUCA

LETTUCE

G. Ledyard Stebbins

Annual to perennial herb; sap milky
Stems erect, 0.5–1.5+ m
Leaves basal and cauline, alternate, entire to pinnately lobed
Inflorescence: heads ligulate, many, in panicles; involucre cylindric; phyllaries in 2–several series; receptacle naked
Flowers few–many; ligules yellow or cream to blue, readily withering
Fruit flattened, short- or long-beaked; pappus of many bristles, falling separately
Species in genus: ± 100 species: ± worldwide temp
Etymology: (Latin: milky)

Introduced

L. ludoviciana (Nutt.) DC.

Biennial 1–2 m
Leaves lanceolate in outline, lobed; lobes widely lanceolate, dentate
Inflorescence open, heads in flower 4–5 mm wide; involucre in fruit 15–22 mm
Flowers 20–56; corolla blue to ± yellow
Fruit 3–4 mm, elliptic, mottled gray and black, transversely roughened, 1-ribbed on each face, unwinged; beak slender, ± = body; pappus 7–12 mm, white
Chromosomes: 2n=34
Ecology: Waste places
Elevation: < 300 m.
Bioregional distribution: Cascade Range Foothills, South Coast
Distribution outside California: native to c US

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bioregional map for LACTUCA%20ludoviciana being generated
 
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Retrieve Jepson Interchange Index to Plant Names entry for Lactuca ludoviciana
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