The common periwinkle, Vinca major (also known as myrtle in the USA) also produces toxic alkaloids, but these don't play any major role in evidence-based medicine. Mabberley (2008) mentions vincamine is used for cerebral vascular disorders, although it's now synthesised from a different plant extract. Locally in its native range, Vinca is used in herbal medicine for treating cuts, toothache, and as a sedative. Five species are known, ranging from Europe to N. Africa to C. Asia (Mabberley 2008).
|Periwinkle, Vinca major. Karori.|
It is however a common weed or wildflower in New Zealand. We have two species, V. major and V. minor. V. minor has sessile leaves, or at least very short petioles, and smaller flowers.
|Periwinkle, Vinca major, Karori. A shoot with a bud and opposite leaves; an opening bud, enlarged; leaves, upper and lower surfaces; and a flower. All line scales 10 mm.|
Mabberley, D.J. 2008. Mabberley's Plant Book. Cambridge.
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. 1988. Flora of New Zealand Vol. 4. Botany Division, DSIR.