The flowering structure has a broad petal-like modified leaf called the spathe that partially clasps a short golden spadix. The edges of the spathe are often folded. It is green on the outside and white on the inside. The close to one-inch spadix is covered with tiny yellow flowers. The dark green leaves are heart-shaped and about 6 inches long. The fruit is a cluster of red berries that forms in late summer. These resemble the berries formed by the Jack-in-the-pulpit plant. Wild calla grows in cool bogs, and on the edges of ponds. It often grows out of the muck at the bottom of shallow bodies of water.

The plant grows 5 to 12 inches tall with the leaves held out of the water on long petioles. Wild calla is a northern species found from Alaska and across southern Canada and the northern United States as far south as Maryland. It is also found in northern Eurasia. In Pennsylvania it is more common in the northern counties, but has also been historically documented in Butler and Somerset Counties.

The blooming period is May to August. The plant used to be abundant in the United States but many populations have suffered from swamp drainage and other habitat degradation. The roots are edible but must be prepared by drying, grinding and heating to remove the acrid chemicals. In early America the root powder was used to make herb cookies when food was scarce. Other common names for this plant are the water arum and bog arum.