Shepherd's Purse is an introduced and widely naturalized erect annual forb growing from 4 to 24 inches tall, sparsely branching. In rich soils it reaches maximum height, in very poor soils it may only be 2 inches tall. The stems are angled and green to reddish green and may have fine appressed hair in the inflorescence.
The leaves are of two types: Basal leaves that are oblong and pinnately lobed (although these leaves are very irregular and may be simply toothed), tufted into a rosette form; and stem leaves that are much smaller, mostly linear, tapering to a pointed tip, stalkless with heart-shaped bases or with two pointed lobes that clasp part way around the stem. Stem leaves are alternate, widely spaced and may be without hair or densely hairy. Basal leaves have both short and white hair on the underside. Plants that germinate late in the season may not have a rosette, instead the flower stalk rises directly from the root.
The inflorescence is a dense raceme of many stalked flowers, appearing first as a tight cluster and then elongating as flowers open while the lower mature flowers form seed pods - a typical arrangement in the Mustard family.
Flowers: Each flower is very small, about 1/8 to 1/4 inch wide, 4-parted, with 4 greenish oblong sepals that become pinkish at flower maturity and 4 white rounded petals which are longer than the sepals. Sepals and calyx are hairy on the outer surface. There are 6 stamens, 4 long inner ones and two short outer ones. This is typical Mustard family arrangement and is known as being "tetradynamous". There are 4 nectar glands - one on each side of the outer stamens. There is a single style with a blunt tip. The flowers can self-fertilize.
Seed: The fruit is a heart-shaped to triangular flat but strongly keeled 2-celled pod known as a "silicle" [length less than 3x the width, otherwise it would be called a "silique"], green initially, turning dull yellow at maturity. These are held horizontally outward to ascending, from the raceme. The remains of the style is seen exerted from the notch at the top of the pod. Individual seeds are oblong, brown and not winged and each cell of the silicle produces about 10 seeds, which have a long vitality in the soil.
Habitat: Shepherd's Purse is found in almost any soil type in untended areas, roadsides, waste areas, even lawns and gardens. It is tolerant of varying moisture levels but needs sun. It spreads by re-seeding and develops a taproot. It is said to be the second most common weed on earth, the first being Chickweed.
Names: The genus Capsella is derived from the Latin capsa, meaning box or case, referring to the flat seed pod shape that resembles the medieval shepherd's wallet or purse, and hence the common name also. The species bursa-pastoris is from the Latin and with bursa meaning 'a purse', the 2-part species name is the Latin for a 'shepherd's purse'. The author name for the plant classification is first - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. His work was amended by ‘Medik’ which refers to Friedrich Kasimir Medikus (1738-1808) German botanist, director of the University of Heidelberg and curator of the botanical garden at Mannheim.
Comparisons: The plant may resemble Field Pennycress, Thlaspi arvense L., in appearance, before and during flowering but the purse-shaped seed pods of Shepherd's Purse are distinctly different from the more oval pods of Pennycress.
Above: The inflorescence of Shepherd's Purse elongates as new flowers open at the top and the seed pods in the distinctive purse shape, open below - a typical mustard family arrangement. The 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. Vol. 2: 158, courtesy USDA-NRCS Plants Database.
Below: The tiny individual flowers are 4-parted with 6 stamens and a single pistil/style. The 2 shorter outer stamens have a pair of nectar glands at their base. Seeds form in a heart-shaped capsule which has the remains of the style at the notch.
Below: The flower calyx has 4 pointed sepals that are hairy on the outside and turn pinkish at flower maturity. 2nd photo is on the long-stalked basal leaf. 3rd photo shows the pale underside of the leaf with both long and short surface hair.
Below: The stem leaves are linear with two pointed lobes that partially clasp the angled stem. Those shown here are hairy on both surfaces.
Below: The basal rosette. Mature seed pod with seeds
Shepherd's Purse was not listed by Eloise Butler as indigenous to the Garden but it was present at the time of Martha Crone's 1951 Garden Census. Later reports do not list it as the curators probable eradicated it when found. In North America there is no area not reporting it. Shepherd's Purse is found in most counties of Minnesota with only widely scattered exceptions. It is the only distinct species of Capsella found in North America.
It is a native of Europe and spread wherever Europeans went, unknown in the New World until the pilgrim fathers arrived. It has an unpleasant odor and a biting taste. Young leaves have been used as potherbs.
Fernald (Ref.#6) reports that in the early 19th Century in the eastern states it was used as a potherb, salad and breadstuff with the leaves gathered in late winter or early spring before they became tough. In Philadelphia in the 1820s it was brought to market in large quantities in the early season. When boiled it approached cabbage in taste, but softer and milder.
Medicinal use: Shepherd's Purse has a long history in folk medicine and modern herbal medicine. The entire plant is used - dried and given in infusions and fluid extracts. A dried infusion will yield a tea which is considered superb for stopping hemorrhages of all kinds. Mrs. Grieve provides many details (Ref. #7).
In The English Physician Enlarged, Culpeper writes " It is too well known to need any description. It helps all fluxes of blood, either caused by inward or outward wounds; as also flux of the belly, and bloody flux, spitting blood, and bloody urine, and stops the terms in women; being bound to the wrists of the hands, and the soles of the feet, it helps the yellow jaundice. The herb being made into a poultice, helps inflammations and St. Anthony's fire. The juice being dropped into the ears heals the pains, noise and matterings thereof. A good ointment may be made of it for all wounds, especially wounds in the head." (Ref. #4b, pg. 298)
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.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"