Memecylon is a plant group in Melastomataceae. It consists of 350-400 species of small to medium-sized trees and shrubs occurring in the Old World tropics.[1][2][3] Memecylon is a monophyletic group basal to the Melastomataceae clade.[4] Memecylon taxa have more than 600 published basionyms.[1][4] Diversity of this group is concentrated in tropical Africa, Madagascar, Sri Lanka, India and Malaysia.[5]
The name Memecylon is derived from 'memaecylon' as used by ancient Greek philosophers Dioscorides and Pliny to describe the red fruits of Arbutus unedo (oriental strawberry tree), an unrelated plant group, alluding to the pink to reddish berries often produced by Memecylon.[4] Some vernacular names in different regions of the world are given below. English: "Blue mist plant", Hindi: Anjan; Malayalam: Aattukanala [ആറ്റുകനല], Kaasaavu: [കാശാവ്], Kaayaampoo: [കായാമ്പൂ]; Odia: Neymaru; Sinhala: Korakaha, Welikaha; Tamil: Kaya.[6]
Memecylon sensu lato can be diagnosed by exstipulate leaves, four-merous bisexual flowers, anthers opening by slits, enlarged connectives bearing terpenoid secreting glands and berries.[7] Memecylon sensu stricto can be distinguished from other Memecyloids by obscure nervation on leaves, non-glandular roughened leaf surface having branched sclerids, imbricate calyx, unilocular ovary and large embryo with thick and convoluted cotyledons.[5]
Species of larger stature have a characteristic brown bark with narrow and sharp furrows, most are small single stemmed trees. However, the bark of many species of smaller stature is varied and may be papery white or smooth dark red-black.[3][7]
Leaves are opposite, short-stalked, elliptic or ovate, mostly with widely spaced pinnate nerves either visible or obscure. Leaves along the twig are all the same size, shiny, glabrous, with entire margins, the node has a characteristic scar between the leaves, the twig bark is typically red, striated and flaky.[3]
The inflorescence is typically dense and axillary. The florets are small (usually less than 5 mm) compared to the other taxa in Melastomataceae, with short fleshy corolla parts. Cymes are bracteate, usually thyrsoid to umbel shaped, often condensed to sessile fascicles of flowers or a few-flowered heads at tips of peduncles. The florets are white or violet, the stamens blue or violet, usually obvious in aggregates, from axillary clusters. Flowers are bisexual, have inferior ovaries, but the parts are otherwise free. The calyx is valvate and there are twice as many stamens as petals.[3][7]