Clammy Ground Cherry is an native perennial forb growing 1 to 2-1/2 feet high on stems where the upper part is covered with dense soft hair. Stems branch frequently, are erect initially but when later in fruit are generally decumbent.
The leaves are larger, broadly ovate, with a pointed tip and a rounded to heart-shaped base leading to a stalk. The margins have irregular wavy teeth or may be entire. Both surfaces are densely hairy with fine white hair, some of which may be glandular.
The inflorescence consists of solitary stalked flowers that rise from the junction of two divergent stems.
Flowers: The green calyx and flower stalk is glandular-hairy, the calyx with 5 triangular lobes. The corolla is funnel shaped, greenish-yellow with 5 shallow lobes. Inside the corolla there is a brownish to purplish spotted area in the center. The five stamens have purple filaments with yellow-ish purple anthers which form around the central ovary.
Seed: Fertile flowers form an inflated calyx slightly longer than wide, that contains a single 1/3 to 1/2 inch diameter round berry, green initially, turning yellow at maturity and containing a number of seeds. The outer husk of the calyx is hairy, closed at the tip and turns brown at maturity.
Habitat: Clammy Ground Cherry grows in dry areas, prairies, woods, in rich to disturbed soils. Full sun to partial sun with moderate moisture. The plants have flowers, buds forming, husks and maturing berries all at the same time. It grows from a rhizomatous root system and can spread vegetatively to form colonies.
Names: The genus Physalis is derived from the Greek word physa, meaning 'a bladder' and referring to the inflated calyx at seed time. The species heterophylla (and the variety name) is a compound word from the Greek with hetero signifying 'diverse' or 'varies' and phylla for 'leaves', thus 'varied leaves'. The author name for the plant classification, ‘Nees’ is for Christian Gottfried Daniel Nees von Esenbeck (1778-1858) German botanist who described around 7000 plant species, authored a number of monographs and was a Professor at Erlangen, Bonn and Breslau. The common name of 'clammy' refers to the touch of the downy leaves. More notes on the species at bottom of the page.
Comparisons: While this species is the most frequently found, there are two others that are only slightly different. P. virginiana the Virginia Ground Cherry, has more lance-like leaves that can be hairy but not as densely so as P. heterophylla. P. longifolia, the Long-leaved Ground Cherry has lance-like leaves that are mostly hairless, as is the stem and the calyx. The flowers have the same structure and color.
Above: The inflorescence consists of solitary stalked flowers that rise from the junction of two divergent stems. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: 1st photo - The flower stalk, calyx and outer surface of the corolla are very hairy. 2nd photo - The inside of the corolla is brownish to purplish spotted. The stamens form around the central ovary.
Below: 1st photo - Leaf margins may be with irregular wavy teeth or entire. Surfaces, especially the underside (2nd photo) are very hairy.
Below: The calyx inflates as the berry forms. The outside is very hairy.
Below 1st photo - The berry, shown here the green stage, turns yellow at maturity and contains many seeds. 2nd photo - the stems have dense hair and usually become decumbent as the season progresses.
Notes: Clammy Ground Cherry is indigenous to the Garden area but not to the Garden itself. Eloise Butler brought in the first plants in Sept. 1920 which see obtained from J. W. Babcocks garden, just east of the Garden itself. Eloise was renting quarters there each summer. Martha Crone noted it in bloom in 1939. In Minnesota, P. heterophylla is found in most counties south of a line between St. Louis and Clay counties. In North America it is found throughout the U.S. and Ontario and Quebec in Canada.
The MN DNR lists three species of Physalis native and found in Minnesota: P heterophylla var heterophylla, Clammy Ground Cherry; P. pubescens var. grisea, Hairy Ground Cherry; and P. virginiana, the Virginia Ground Cherry. The first and the last are rather widespread. The University of Minnesota Herbarium also reports two other species that have been reported but without specimens ever collected. These are P. longifolia, Long-leaf Ground Cherry; and P. philadelphica, Mexican Ground-cherry. The latter is known in Iowa and Wisconsin. Two other species from the Nightshade family in Minnesota are found in the Garden - Black Nightshade and Climbing Nightshade.
The Genus Physalis: An alternate name for these species is "husk-tomato" - the small fruit resembles a tomato and is said to taste like one, although strongly, and it ripens within the inflated calyx - thus a "husk". Some species are annuals and some grow from rhizomatous roots and are perennial. They are widespread. As members of the Nightshade family, they have been sought out for medicinal purposes. One of the species not reported to be in Minnesota, P. longifolia, the Long-leaved Ground Cherry, also known as the Wild Tomatillo, is of particular interest in cancer research. This article from the University of Kansas explains that. Domesticated tomatillos have long been used as foodstuff by Native American peoples. Harrington (Ref.#9) and others report that most fecal samples from archaeological sites in the southwest contain seeds of the species.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"