Jepson Flora Project: Jepson Interchange    

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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
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Robert L. Schlising

Annual, perennial herb, generally monoecious; hairs often hardened by calcium deposits
Stems trailing or climbing, 1–many; tendril generally 1 per node, often branched
Leaves generally simple, alternate, generally palmately lobed, veined, petioled; stipule 0
Inflorescences at nodes; staminate flowers in racemes, panicles, small clusters, rarely solitary; pistillate flowers generally solitary
Flower unisexual in CA, radial; hypanthium > ovary; calyx (apparently 0 or) generally 5-lobed; corolla rotate or cup-shaped, generally 5-lobed; stamens 3–5 (or appearing 1–3 from fusion), anthers often > filaments, twisted together; ovary ± inferior, chambers generally 5, placentas parietal, ± growing into chambers, styles 1–3, stigmas generally lobed, large
Fruit: berry (sometimes drying) or capsule (irregularly dehiscent), generally gourd- or melon-like
Seeds 1–many
Genera in family: 100 genera, 700 species: especially tropical; some cultivated (Citrullus ; Cucumis ; Cucurbita ; Sechium , chayote). Citrullus colocynthis var. lanatus has been reported as a weed in DSon.



Perennial, sometimes temporarily dioecious; tuber large
Stem ± scabrous or hairy, becoming glabrous; tendril branched
Leaf ± round, cordate, ± 5–7-lobed
Inflorescences: staminate flowers in racemes or panicles with nonglandular axes (or 1 flower per axil early in season); pistillate flower 1 per axil (generally same axil as staminate)
Flower: sepals 0; corolla 3–15 mm wide (wider in pistillate), cup-shaped to rotate, white or cream to yellowish green; stamens fused, anthers twisted together; stigma 1, ± hemispheric
Fruit: capsule, irregularly dehiscent, ± symmetric, 3–20 cm, round, ovate, or oblong, sometimes tapered to a beak, ± prickly
Seed generally > 1 cm
Species in genus: 7 species: w North America
Etymology: (Hebrew: bitter, from taste of all parts)
Reference: [Schlising 1969 Amer J Bot 56:552–561]
Extremely variable in habit, leaves, sexual expression; presumed hybrids occur where species overlap. Sometimes included in Echinocystis.


M. watsonii (Cogn.) Greene

Herbage glaucous
Flower: corolla deeply cup-shaped, white
Fruit 2–3.5 cm, ± round, often striped dark green; prickles ± 0 to dense, flexible, often hooked
Seeds 1–4, 11–14 mm, ± round
Ecology: Shrubby areas, forest edges
Elevation: < 1200 m.
Bioregional distribution: Inner North Coast Ranges, Cascade Range Foothills, n Sierra Nevada Foothills, Sacramento Valley.

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bioregional map for MARAH%20watsonii being generated
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Retrieve Jepson Interchange Index to Plant Names entry for Marah watsonii
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