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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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

ARACEAE

ARUM FAMILY

Elizabeth McClintock

In CA perennial herb, terrestrial or aquatic, from short, generally erect caudex, often monoecious; elsewhere shrub, vine, or growing on other plant
Stems sometimes above ground in addition to caudex
Leaves simple or compound, basal (or cauline and 2-ranked)
Inflorescence: generally spike, fleshy, generally ill-smelling; flowers generally many, bisexual or pistillate below, staminate above; bract subtending spike 1, generally showy (petal-like), generally > spike, sometimes sheathing
Flower: perianth parts 4 or 6, free or fused; stamens generally 0, 4, or 6, free or fused; ovary superior to half-inferior and sunken in inflorescence axis, chambers 1–3, stigma ± sessile
Fruit: berry
Seeds 1–many
Genera in family: ± 110 genera, 1800 species: generally tropical, subtropical. Some cultivated for food (Colocasia , taro) or ornamental (Philodendron, Anthurium )
Reference: [Wilson 1960 J Arnold Arbor 41:47–63]
Needle-like crystals in most tissues cause intense irritation when chewed; those of Dieffenbachia, dumb-cane, may induce temporary speechlessness.

PISTIA

WATER-LETTUCE


Species in genus: 1 sp
Etymology: (Greek: liquid, from aquatic habitat)

Introduced

P. stratiotes L.

Perennial, aquatic, floating, monoecious, spreading from stolons; roots many
Stem short, corm-like
Leaves basal, whorled, sessile; blade < 20 cm, < 7 cm wide, widely wedge-shaped, tip truncate or notched, velvety-hairy
Inflorescence: spike < bract, fused to bract (except tip); bract ± 1.5 cm, hairy outside, upper half open, ± flared, reflexed, lower half closed
Flowers: perianth 0
Staminate flowers several, whorled, sessile; stamens 2–8
Pistillate flower 1; ovary ± superior, chamber 1, style stout, curved, persistent
Fruit green
Seeds many
Ecology: Ditches
Elevation: < 50 m.
Bioregional distribution: e Sonoran Desert (Colorado River), expected elsewhere
Distribution outside California: to se US, tropical worldwide

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