Calla

Calla is a genus of flowering plant in the family Araceae, containing the single species Calla palustris (bog arum, marsh calla, wild calla, squaw claw, and water-arum ).

Description
It is a rhizomatous herbaceous perennial plant growing in bogs and ponds. The leaves are rounded to heart-shaped, 6 – long on a 10 – petiole, and 4 – broad. The greenish-yellow inflorescence is produced on a spadix about 4 – long, enclosed in a white spathe. The fruit is a cluster of red berries, each berry containing several seeds.

The plant is very poisonous when fresh due to its high oxalic acid content, but the rhizome (like that of Caladium, Colocasia, and Arum) is edible after drying, grinding, leaching and boiling.

Taxonomy
The genus formerly also included a number of other species, which have now been transferred to the separate genus Zantedeschia. These plants from tropical Africa, however, are still often termed "calla lilies" but should not be confused with C. palustris.

Distribution
It is native to cool temperate regions of the Northern Hemisphere, in central, eastern and northern Europe (France and Norway eastward), northern Asia and northern North America (Alaska, Canada, and northeastern contiguous United States).