Plants of the Eloise Butler Wildflower Garden

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 (these leaves can be 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 (auricles) 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. The basal leaves may have withered away by flowering time. Plants that germinate late in the season may not have a rosette, instead just 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 from bottom to top 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 pair placed on each side of the two 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 in 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'. Over the centuries, the plant has had various Latin names, beginning with Thlaspi bursa-pastoris.

That name was assigned by the first person to classify the plant in 1753 - '(L.)'- which refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. His work was amended in 1792 and the current name assigned 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. Pepper Grass, Lepidium densiflorum, has similar seed pods but the leaves do not have auricles and the flower petals are shorter than the sepals. Comparison drawings are show below.