Common Name: ARUM FAMILY Habit: Perennial herb, [shrub, vine], terrestrial [growing on other plants or not], or aquatic, sometimes free-floating, then sometimes much reduced, in dense, clonal populations, 0.4--10 mm, flat and tongue-shaped to spheric, not differentiated into stems and leaves, new plants produced in budding pouch at base or along margins, sometimes overwintering on bottom as dense, rootless, starch-filled daughter plant (winter bud); often from short, generally erect caudex; roots 0--many; often monoecious. Stem: sometimes above ground in addition to caudex, or not differentiated from plant body. Leaf: simple or compound, basal (or cauline, 2-ranked), or not differentiated from plant body. Inflorescence: generally spike, fleshy, generally ill-smelling, or flower 1, rarely seen, minute, appearing like 2--3 unisexual flowers, often sheathed by minute membrane; flowers bisexual or pistillate below, staminate above; bract subtending spike 1, generally showy (petal-like), generally > spike, sheathing or not. Flower: perianth parts 0, 4, 6, free or fused; stamens 0--4, 6, free or fused; ovary superior to 1/2-inferior and sunken in inflorescence axis, chambers 1--3, stigma +- sessile. Fruit: berry or achene-like, winged or not. Seed: 1--many, often ribbed. Genera In Family: +- 114 genera, 1850 species: generally tropics, subtropics some cultivated for food, ornamental in ponds, aquaria (Colocasia, taro) or ornamental (Philodendron, Anthurium). Note: Since TJM (1993), including Lemnaceae, and except Acorus, now in Acoraceae (the sole member in California, Acorus calamus L., is an historical waif). Pistia stratiotes L. is a waif. Pinellia ternata (Thunb.) Breitenbach possibly naturalized in California. In taxa once included in Lemnaceae, vein number per plant body best determined using backlight. Unabridged Note: Since TJM (1993), including Lemnaceae, except Acorus, now in Acoraceae (the sole representative of the family in California, Acorus calamus, judged to be an historical waif in California and therefore here except). Incl smallest of all known angiosperms (Wolffia globosa) as well as world's most massive inflorescence (spike of Amorphophallus titanum, Titan Arum, to 4 m in circumference). Needle-like crystals in most tissues cause intense irritation when chewed; those of Dieffenbachia, dumb-cane, may induce temporary speechlessness. Incl of fossil evidence in cladistic analyses indicate Lemnaceae and Pistia form a monophyletic group within Araceae (Stockey et al.), a position now generally accepted (see Les et al.). Pinellia ternata (Thunb.) Makino ex Breitenbach introduced, possibly naturalized in California. Taxa formerly included in Lemnaceae may be very invasive. In taxa formerly included in Lemnaceae, vein number per plant body best determined using backlight. Peltandra virginica (L.) Schott & Endl., included in TJM (1993), reportedly spread from ornamental pool introduction in 1970 to nearby reserviors, but degree of reproduction or even persistence there unknown. eFlora Treatment Author: Thomas J. Rosatti, except as noted Scientific Editor: Bruce G. Baldwin, Thomas J. Rosatti.
Etymology: (Greek: liquid trough, from aquatic habitat)
Pistia stratiotes L.
WAIF Habit: Perennial herb, aquatic, floating, monoecious, spreading from stolons; roots many, +- plumose. Stem: short, corm-like. Leaf: basal, sessile; blade < 20 cm, < 7 cm wide, widely wedge-shaped, grooved lengthwise, velvety-hairy, tip +- truncate, notched or toothed. Inflorescence: exceeded by bract; peduncle +- 0; bract +- 1.5 cm, hairy abaxially, +- ciliate, proximally +- closed, distally open. Flower: perianth 0. Staminate Flower: several, whorled, sessile; stamens 2--8. Pistillate Flower: 1; ovary +- superior, chamber 1, style stout, curved, persistent. Fruit: green. Seed: many. Chromosomes: 2n=28. Ecology: Ditches; Elevation: < 50 m. Bioregional Distribution: DSon (near Salton Sea, Colorado River); Distribution Outside California: to southeastern United States, tropics worldwide. Flowering Time: May--Oct Unabridged Note: Whether native to any part of United States unresolved; see ICPN for reasons to treat as waif in California; a serious aquatic weed outside US. Great variation has resulted in many names, but is mostly environmental. Jepson eFlora Author: Thomas J. Rosatti Index of California Plant Names (ICPN; linked via the Jepson Online Interchange) Noxious Weed listed on the CDFA Weed Pest Ratings table View the CDFA Pest Rating page for Pistia stratiotes Weed listed by Cal-IPC Previous taxon: Pistia Next taxon: Spirodela
Citation for this treatment: Thomas J. Rosatti 2012, Pistia stratiotes, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=38415, accessed on December 02, 2024.
Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on December 02, 2024.
No expert verified images found for Pistia stratiotes.
MAP CONTROLS 1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurrence).
MAP LEGEND View all CCH records All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
READ ABOUT YELLOW FLAGS
CCH collections by month
Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).