This week, I’m featuring Wild Calla (Calla palustris) as one of our local wildflowers that begins to bloom at this time.
In botany, there is a scale called the “Coefficient of Conservatism.” The scale represents how tolerant a plant is to human disturbances and how representative it is to a pre-settlement natural community of plants. Coefficients of conservatism (“C” or CoC values) are increasingly being used to prioritize natural areas for conservation as well as for the monitoring of outcomes of habitat restoration projects. Species least tolerant of human disturbance and with an affinity for high-quality native habitats are placed in category “10.” Wild Calla is placed in category “10.”
Description:
Wild Calla is a native erect perennial that is semi-aquatic typically growing 5 to 10 inches high. The leaves emerge first and are all basal, rising from the rhizome. They are 2–4½” long and a little less across, green, toothless, somewhat waxy and heart shaped with a sharp pointed tip that is often curved upward and inward (involute). Each leaf has a central vein that extends to about one-third of its length, from which there develops numerous parallel lateral veins that curve upward toward the leaf tip. The upper side of each leaf stem (petiole) is shallowly concave, while its lower side is round.
The flower stalk is a separate stem that is usually shorter than the upright leaves. It has a knob shaped 1 to 2 inch spadix that is densely covered with numerous tiny greenish white flowers across its entire surface. Directly behind the spadix and partly surrounding it is a broad white spathe that is oval to elliptical in shape, hairless, and 1½–2½” in length that tapers abruptly into a narrow linear tip up to 1/3″ long and strongly involute (rolled tightly inward). Occasionally plants have been found with two or three spathes. Sometimes the back of the spathe is light green while it is in bloom; afterwards, the spadix and spathe turn green.
The fertilized flowers are replaced by globelike-ovoid berries with short tapered beaks. As the berries develop, the spadix swells in size. Immature berries are green or greenish yellow, but they become bright red and 1/3–1/2″ across at maturity. Each pear-shaped berry contains gelatinous flesh and 2-14 seeds. The mature seeds are ¼” long, cylindric and somewhat flattened in shape, brown to dark brown, and minutely pitted in regular horizontal rows.
Culinary and Medicinal Uses:
CAUTION! – All parts of this plant are poisonous due to the toxin calcium oxalate. Causes severe pain in mouth if ingested including burning and swelling of lips, mouth, tongue, and throat.
The rhizome is edible after it is dried, processed and then the resulting meal is boiled. It can then be used as flour, but not by itself – it should be mixed with regular wheat flour. Accounts of this go back to Linnaeus where the resulting product was called ‘Missen bread.’ Linnaeus stated that the resulting bread “proves as tough as rye bread, but is perfectly sweet and white. It is really, when new, extremely well-flavored.” (SOURCE: Fernald, Merritt L. & Alfred C. Kinsey. Edible Wild Plants of Eastern North America. Harper & Row. 1958)
American Indians traditionally used this plant for limited medicinal purposes. For example, a tea made from the dried root has been used in the treatment of flu and shortness of breath, and as a poultice on swellings and snakebites.
Wildlife Value:
The flowers are visited primarily by flies, including Syrphid flies and carrion flies, and beetles (leaf beetles – Chrysomelidae and sap-feeding beetles – Nitidulidae). However, this is one of the very few plants known to be pollinated by snails as they are attracted by the flower’s scent.
The foliage is toxic because it contains calcium oxalate; this substance is highly irritating to the gastrointestinal tract of animals and, as such, they avoid browsing it.
Where Found Locally:
Wild Calla is found in bogs and marshes as it is a plant of shallows, cold water, and wet soils.
- Dyken Pond Environmental Center (east of Koch Trail)
- Veterans Memorial Park
Curious By Nature 