Depending on your point of view, this is either an invasive weed or a cheery harbinger of spring. It comes from Europe, and it makes itself at home in our lawns, where it politely refuses to exceed the height of the grass around it. There are people who eat it as a salad herb, so it can’t be all bad. It’s one of the first things to bloom in the spring, appearing along with the crocuses and persisting through daffodil season. This patch was blooming in a lawn in Beechview in early April.

Gray describes the genus and the species:

CARDÂMINE [Tourn.] L. Bitter Cress. Pod linear, flattened, usually opening elastically from the base; the valves nerveless and veinlees, or nearly so; placentae and partition thick. Seeds in a single row in each cell, wingless; the funiculus slender. Cotyledons accumbent, flattened, equal or nearly so, petiolate.— Mostly glabrous perennials, leafy-stemmed, growing along watercourses and in wet places. Flowers white or purple. (A Greek name, used by Dioscorides for some cress, from its cordial or cardiacal qualities.)

Root mostly biennial or annual; leaves pinnately 5-11-foliolate, flowers small, white.

Stamens 4; leaflets strigose-hispid upon the upper surface.

С. hirsuta L. Leaves chiefly radical, with short and broad leaflets, but those on the erect stem reduced and with narrow leaflets; pods erect, on ascending or appressed pedicels. — Moist places, s. l’a. to N. C, and “Mich.” (Eu.) Perhaps introduced. A doubtful specimen from w. Mass. (Miss Vail).

An unimposing little weed, but it delights children by producing round, flat seedpods that look like coins. This one grew in a meadow near Cranberry, where it was blooming and already seeding in the middle of June.

Gray describes the genus and the species:

THLASPI [Tourn.] L. PENNY CRESS
Pod orbicular, obovate, or obcordate, flattened contrary to the narrow partition, the midrib or keel of the boat-shaped valves extended into a wing. Seeds 2-8 in each cell. Cotyledons accumbent. Petals equal.—Low plants, with root-leaves undivided, stem-leaves arrow-shaped and clasping, and small white or purplish flowers. (Name from thlaein, to crush, from the flattened pod.)

T. arvense L. (FIELD P. or MITHRIDATE MUSTARD.) Smooth annual; lower leaves wing-petioled, the upper sagittate-clasping; broadly winged pod 1.2 cm. in diameter, deeply notched at top; style minute. Waste places; not common, except along our northern borders, where too abundant and called “FRENCHWEED.” (Nat. from Eu.)

Now known as Sinapis arvensis; also formerly called Brassica kaber. A common weed along roadsides and in fields. The larger flowers easily distinguish it from the other wlid mustards.

Gray describes the genus and the species:

BRASSICA [Tourn.] L. MUSTARD. TURNIP
Annuals or biennials, with yellow flowers. Lower leaves mostly lyrate, incised, or pinnatifid. (The Latin name of the Cabbage.)

B. ARVENSIS (L.) Ktze. (CHARLOCK.) Knotty pods fully one third occupied by a stout 2-cdged beak; upper leaves rhombic, scarcely petioled, merely toothed; fruiting pedicels short, thick; pods smooth or rarely bristly. 4 cm. long. (B. Sinapistrum Boiss.; Sinapis arvensis L.) Noxious weed in grainfields, etc. (Nat. from Eu.)

Cut-Leaf Toothworts are common in rich open woods; this one was blooming on a wooded hillside in Mount Lebanon in late April. The leaves are distinctive: they grow in whorls of three, and they are narrow and deeply divided, with jagged teeth on each lobe. The flowers of Broadleaf Toothwort (Cardamine diphylla) are similar, but the leaves are very different.

Gray puts the Toothworts in the genus Dentaria, and lists this one as Dentaria laciniata.

DENTARIA [Tourn.] L. TOOTHWORT. PEPPER-ROOT
Pod lanceolate, flat. Style elongated. Seeds in one row, wingless, the funiculus broad and flat. Cotyledons petioled, thick, very unequal, their margins somewhat infolding each other. —Perennials, of damp woodlands, with long fleshy sometimes interrupted scaly or toothed rootstocks, of a pleasant pungent taste; stems leafless below, bearing 2 or 3 petioled compound leaves about or above the middle, and terminated by a corymb or short raceme of large white or purple flowers. (Name from dens, a tooth.)

D. laciniata Muhl. Tubers deep-seated; stems pubescent above; cauline leaves 3, whorled or nearly so, the lateral leaflets deeply cleft, glabrous or pubescent, the segments linear to narrowly oblong, conspicuously gash-toothed; basal leaves, when present, similar; flowers white or purplish; calyx 6-9 mm. long; petals 1-2 cm. long. Rich damp woods, w. Que. and Vt. to Minn., and southw. Apr., early May.

Pittsburghers usualy call it “phlox,” but this ubiquitous late-spring flower is really a member of the mustard or crucifer family, as you can tell by the four-petaled flowers (real Phlox flowers have five petals). It came from Europe as a garden flower and quickly made itself at home. It would be hard to conjure up any inhospitable feelings toward this welcome guest, whose bright flowers decorate roadsides and back yards everywhere (these flowers were blooming in Mount Lebanon in late May). Each colony blooms in a mixture of colors from deep magenta to white, and many plants grow flowers with splashes or stripes of contrasting colors.

Gray describes the genus and the species:

HESPERIS [Tourn.] L. ROCKET
Pod linear, nearly cylindrical; stigma lobed, erect. Seeds in 1 row in each cell, oblong, marginless. Cotyledons incumbent. Biennial or perennial, with serrate sessile or petiolate leaves, and large purple flowers. (Name from hespera, evening, from the evening fragrance of the flowers.)

H. MATRONALIS L. (DAME’S VIOLET.) Tall: leaves lanceolate, acuminate; pods 5-10 cm. long, spreading. Sometimes cultivated, and spreading to roadsides, etc. (Introd. from Eu.)