Vinca minor is a perennial, evergreen vine. The stems are smooth, green, round, sometimes pubescent, and often hollow, although it does produce woody rhizomes. The plant forms thick sprawling mats with the flowering stems more or less erect. Its leaves are simple and arranged oppositely on the stem, though sometimes the nodes are so close together that two pairs of leaves seem to form a whorl.

The leaves are oblong-ovate to elliptical, approximately 2-5 cm long and 1-2.5cm wide, with petioles 1-3mm long. They are glossy, pinnately veined, entire, and have margins that curl away from the sun. The veins are usually white, and latex can be found in the stems and leaves.

The flower is perfect and without odor. It is showy, purple to blue and occasionally white, borne singly in an axillary position on a 1-1.5cm pedicel. The calyx is five-lobed, green, and glabrous. The petals radiate from the center in an almost pinwheel-like shape forming an 8-12mm long tube with a white crest that is finely pubescent near the base. The corolla is approximately 2.5 cm in diameter. The flower has five stamens; the anthers are yellow and their tips are finely pubescent. The superior green gynoecium is two-carpellate. The style is green; the stigma is densely pubescent and white.

Source: http://climbers.lsa.umich.edu/?p=170