Calla palustris L.
Wild Calla, Water Arum, Wild-calla
These North American native plants inhabit swamps, seasonally flooded bogs, stream banks, ditches, quagmires, and muddy lake shores.
Plants: 4-16" (10-40 cm) in size, partially submerged. They have a weak odor that is unpleasant to people, but that flies and beetles and even snails find appealing. Plants can form thick colonies.
Leaves: Leaves emerge on stalks up to 16" (40 cm), above a submersed rootstalk. Leaves are heart-shaped (ovate), waxy, smooth, and smooth-edged, with edges tending to curl inward. There is a single leaf, 1¾-4½" (5-12 cm) long, atop each stalk.
Flowers: A single white, waxy, heart-shaped “petal,” attached to the stalk at its base, appears to be the flower, but this is really a spathe, a specialized protective leaf. The actual flowerhead, called the spadix, is about 1" (2.5 cm) long and ½" (1.3 cm) around, also whitish, and covered with tiny white/green flowers that lack petals. The upper part of the flowerhead has unisexual staminate flowers, while the lower part is bisexual. The flower is supported on a stem 3-12" (7.6-30 cm) above the water line. They appear from June to July.
Fruits: Irregular, angled, but roughly pear-shaped berries up to ½" (1.3 cm) around, and bright red.
Edibility: Poisonous. . All parts of the plant are toxic. Calcium oxalate is probably the single most toxic component. Nevertheless, in times of poverty, some peoples processed the plant in a way that reduced its toxicity, and mixed it with other foods.
Calla palustris at the Central Yukon Species Inventory Project
Calla palustris on www.luontoportti.com
Calla palustris at Minnesota Wildflowers
Calla palustris on gobotany.nativeplanttrust.org
Calla palustris description by Thomas H. Kent, last updated 11 Jul 2019.
Range: Zones 2-6: