|Madagascar rosy periwinkle|
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Catharanthus roseus, commonly known as the Madagascar rosy periwinkle, is a species of Catharanthus native andendemic to Madagascar. Other English names occasionally used include Cape periwinkle, rose periwinkle, rosy periwinkle, and “old-maid”.
Two varieties are recognized
- Catharanthus roseus var. roseus
- Synonymy for this variety
- Catharanthus roseus var. angustus (Steenis) Bakh. f.
- Synonymy for this variety
It is an evergreen subshrub or herbaceous plant growing 1 m tall. The leaves are oval to oblong, 2.5–9 cm long and 1–3.5 cm broad, glossy green, hairless, with a pale midrib and a short petiole 1–1.8 cm long; they are arranged in opposite pairs. The flowers are white to dark pink with a darker red centre, with a basal tube 2.5–3 cm long and a corolla 2–5 cm diameter with five petal-like lobes. The fruit is a pair of follicles 2–4 cm long and 3 mm broad.
In the wild, it is an endangered plant; the main cause of decline is habitat destruction by slash and burn agriculture. It is also however widely cultivated and isnaturalised in subtropical and tropical areas of the world.
Cultivation and uses
The species has long been cultivated for herbal medicine and as an ornamental plant. In Ayurveda (Indian traditional medicine) the extracts of its roots and shoots, though poisonous, is used against several diseases. Intraditional Chinese medicine, extracts from it have been used against numerous diseases, including diabetes, malaria, and Hodgkin’s lymphoma. The substances vinblastine and vincristine extracted from the plant are used in the treatment of leukemia  and Hodgkin’s lymphoma.
As an ornamental plant, it is appreciated for its hardiness in dry and nutritionally deficient conditions, popular in subtropical gardens where temperatures never fall below 5 °C to 7 °C, and as a warm-season bedding plant in temperate gardens. It is noted for its long flowering period, throughout the year in tropical conditions, and from spring to late autumn, in warm temperate climates. Full sun and well-drained soil are preferred. Numerous cultivars have been selected, for variation in flower colour (white, mauve, peach, scarlet and reddish-orange), and also for tolerance of cooler growing conditions in temperate regions. Notable cultivars include ‘Albus’ (white flowers), ‘Grape Cooler’ (rose-pink; cool-tolerant), the Ocellatus Group (various colours), and ‘Peppermint Cooler’ (white with a red centre; cool-tolerant).
C. roseus is used in plant pathology as an experimental host for phytoplasmas. This is because it is easy to infect with a large majority of phytoplasmas, and also often has very distinctive symptoms such as phyllody and significantly reduced leaf size.
C. roseus is known as “Noyon Tora”(Assamese:নয়নতৰা)in Assamese,”noyontara” (Bengali: নয়নতারা) in Bengali, sadaphuli (Marathi: सदाफुली) in Marathi, boa-noite(“good night”) and maria-sem-vergonha (“shameless maria”, name shared with Impatiens and Thunbergia alata) in Portuguese (American), vinca-de-madagáscar,vinca-de-gato (“cats’ vinca”), vinca-branca (white vinca), vinca or boa-noite in Portuguese (European), vinca del Cabo, vinca rosa (“pink vinca”) or vinca rosada(“roseous vinca”) in Spanish, putica (“little whore”) in Venezuela and nityhakalyani in Tamil (Tamil: நித்யகல்யாணி பூ).