Periwinkle (Vinca minor)
This ornamental ground cover has made itself at home all over the city. It persists indefinitely once it establishes itself, and spreads in shady areas too dim for other flowers. It also goes by the common names Myrtle and Cemetery Vine—the latter because its sober habits, dark leaves, and general indestructibility made it a favorite planting at cemeteries. This patch grew in the woods in West End Park, where it was blooming in the middle of April.
Gray describes the genus and the species:
VÍNCA L. PERIWINKLE.. Calyx-lobes acuminate. Corolla-tube funnel-form; the limb salver-form. Stamens inserted below the throat; filaments short. Style slender. Pods short-cylindric. Seeds rough. —Smooth trailing hardy plants (or in the Tropics tender annuals) with evergreen firm leaves and axillary flowers. (Ancient Latin name of uncertain derivation.)
V. minor L. (COMMON P., “MYRTLE.”) Spreading by creeping stems; leaves glossy, ovate to oblong, 1.5-3 cm. long, flowers peduncled; corolla blue, with truncate lobes. —Roadsides, etc., escaped from cultivation. Apr.-Juue. (Introd. from Eu.)