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Scale bar 10mm. Copyright CSIRO
Leaves and Flowers. Copyright CSIRO
10th leaf stage. Copyright CSIRO
Cotyledon stage, epigeal germination. Copyright CSIRO
Catharanthus roseus (L.) G.Don
Don, G. (1837) A General History of Dichlamydeous Plants 4: 95. Type: ?.
Ammocallis rosea (L.) Small, Fl. S. E. United States: 935(1903), Type: ?. Lochnera rosea (L.) K.Schum., Die Naturlichen Pflanzenfamilien 4(2): 145(1895), Type: ?. Pervinca rosea (L.) Moench, Methodus: 463(1794), Type: ?. Vinca rosea L., Systema Naturae ed. 10, 2: 944(1759), Type: (not cited). Catharanthus roseus var. albus G.Don, Gen. Hist. 4: 95(1837), Type: Not designated. Catharanthus roseus var. occellatus G.Don, Gen. Hist. 4: 95(1837), Type: Not designated. Vinca rosea var. occellatus (G.Don) F.M.Bailey, The Queensland Flora 3: 984(1900), Type: ?. Vinca rosea L. var. rosea, The Queensland Flora 3: 984(1900), Type: ?.
Periwinkle, Madagascar; Periwinkle, Pink; Periwinkle, Rose; Periwinkle, Rosey; Rosy Periwinkle; Rose Periwinkle; Pink Periwinkle; Old Maid Flower; Madagascar Periwinkle; Bright-eyes; Graveyard Plant
Usually flowers and fruits as a shrub about 1 m tall but also flowers when smaller.
Leaves, petioles and twigs produce a milky exudate. Leaf blades about 3.5-7 x 1.9-3.5 cm, obovate with a small point at the apex. Veins regularly spaced but not forming definite loops inside the blade margin.
Flowers usually paired in the leaf axils. Calyx lobes +/- linear, pubescent. A ring of white hairs at the base of the corolla lobes surround the orifice of the corolla tube. Lobes about 22 mm long, tube about 27 mm long. Pollen white. Two comparatively large, narrowly triangular glands present at the base of the pubescent carpels. Carpels united only by the style at the apex. Stigma +/- tower shaped like the tower of a mosque.
Fruits cylindrical, about 25-35 mm long, pubescent on the outer surface, hairs erect. Fruits may fall from the plant when they are still green. Funicle attached in the middle of a saucer-shaped depression in the side of the seed. Testa rugose. Embryo green. Cotyledons slightly wider than the radicle.
Cotyledons spathulate, about 10-12 x 5-6 mm, glabrous. First pair of leaves elliptic, opposite. At the tenth leaf stage: leaf blade elliptic, about 30-40 x 10-15 mm. Stipules small, about 1 mm long, more than two per leaf. Stems longitudinally grooved and producing a milky exudate when cut. Reticulate veins run at right angles to the midrib.
Distribution and Ecology
An introduced species originally from Madagascar, now naturalized in Australia in WA, NT, CYP(?), NEQ and southwards as far as south-eastern Queensland. Altitudinal range from near sea level to 750 m. Usually grows in disturbed areas near habitation or close to the sea.
Suspected of being poisonous to stock but the evidence is not conclusive. Everist (1974).
This species is a rich source of alkaloids and is generally regarded as toxic, although it is seldom eaten by domestic animals.
Commonly cultivated and will survive hot dry conditions.
This species is probably one of the most thoroughly investigated plants in the world. So far it has been shown to contain 75 distinct alkaloids, most of which were previously unknown. Cribb (1981).
Shrub (woody or herbaceous, 1-6 m tall)