in C. G. D. Nees, Horae Phys. Berol., 73. 1820.
Herbs, annual or perennial, scapose or caulescent, from taproots; sap colorless or clear orange. Stems leafy. Leaves alternate, basal and sometimes cauline, petiolate; blade 1-4× pinnately deeply lobed, lobes of each order usually 3; ultimate lobes narrow. Inflorescences terminal, cymose with bracts present, or 1-flowered. Flowers: receptacle dilated, forming cup beneath calyx, sometimes with free rim; perianth and androecium perigynous; sepals 2, connate, calyptrate, deciduous as unit; petals 4, rarely more (doubled flowers), obovate to obcuneate, with satin sheen from microscopic linear grooves; stamens 12-many; pistil 2-carpellate; ovary 1-locular; style absent; stigmas 4-8, spreading, linear. Fruits capsular, cylindric, 2-valved, dehiscing from base along placentas, often explosively. Seeds many, tan, brown, or black, spheric to ovoid, reticulate, ridged and burlike, or pitted, aril absent. x = 6, 7.
w North America (United States), nw Mexico.
Species 12 (10 in the flora).
Eschscholzia species are introduced from cultivation elsewhere in warm-temperate regions worldwide.
Clark, C. and J. A. Jernstedt. 1978. Systematic studies of Eschscholzia (Papaveraceae). II. Seed coat microsculpturing. Syst. Bot. 3: 386-402.
Ernst, W. R. 1964b. The genus Eschscholzia in the south Coast Ranges of California. Madroño 17: 281-294.
|1||Receptacular cup with spreading free rim.||Eschscholzia californica|
|1||Receptacular cup without spreading free rim.||> 2|
|2||Plants scapose; ultimate leaf lobes acute; petals yellow; calyx glabrous.||> 3|
|2||Plants caulescent, with flowers borne on leafy stems (not readily apparent in young plants); ultimate leaf lobes acute or obtuse; petals yellow or orange; calyx glabrous or pubescent.||> 4|
|3||Seeds burlike with raised ridges; petals 12 mm or shorter; California (Great Central Valley, Sierra Nevada foothills).||Eschscholzia lobbii|
|3||Seeds minutely pitted, not burlike; petals usually 12 mm or longer; California, Arizona, Nevada, and Utah (Mojave and Sonoran deserts).||Eschscholzia glyptosperma|
|4||Calyx pubescent; buds nodding; leaf blades sparsely pubescent.||> 5|
|4||Calyx glabrous; buds nodding or erect; leaf blades essentially glabrous, never consistently pubescent.||> 6|
|5||Petals orange or deep yellow throughout, 15–40 mm; receptacles broader than 1.5 mm.||Eschscholzia lemmonii|
|5||Petals yellow, sometimes with orange spot at base, 10–20 mm; receptacles narrower than 1.5 mm.||Eschscholzia hypecoides|
|6||Older buds nodding.||> 7|
|6||Older buds erect.||> 8|
|7||Leaf blades bright green or yellow-green, terminal lobes slender, acute.||Eschscholzia parishii|
|7||Leaf blades grayish or bluish green, terminal lobes broadened at apex, usually obtuse.||Eschscholzia minutiflora|
|8||Receptacle somewhat swollen and translucent distally, usually broader than 2 mm.||> 9|
|8||Receptacle strictly obconic, not translucent distally, narrower than 2.5 mm.||> 10|
|9||Petals (15–)20 mm or more, orange or deep yellow; California (Kern County).||Eschscholzia lemmonii|
|9||Petals 15 mm or less, yellow; inland California Coast Ranges.||Eschscholzia rhombipetala|
|10||Flower buds blunt or rounded short-acuminate, tip less than 1/4 length of bud; ultimate leaf lobes elongate, giving diffuse appearance; California Channel Islands.||Eschscholzia ramosa|
|10||Flower buds apiculate-acuminate, tip usually more than 1/4 length of bud; ultimate leaf lobes short, giving compact appearance; California and Oregon mainland foothills.||Eschscholzia caespitosa|