Most Singaporeans would be familiar with the grass jelly that is served as a chilled dessert, served commonly either in strips soaked in soybean milk or in cube form bathed in sugar syrup. In Chinese, this foodstuff is referred to as ‘xiancao’ (仙草, literal translation means ‘fairy herb’) and ‘cincao’ in Malay.
Whilst most of us are familiar with the foodstuff itself, not many would be familiar with the plant. The plant that produces the black grass jelly in part of the world is a species from the genus Mesona and is a member of the mint family (Lamiaceae). Two species of Mesona, namely, M. chinensis and M. parviflora, have been reported to be used to make grass jelly. From what I have researched, M. chinensis appears to be the one used in southeast China and Taiwan while M. parviflora seems to be more popular in Indonesia. Chinese refer to M. chinensis as ‘凉粉草’ (liang fen cao).
Plant Resources of South East Asia states that the two species may be conspecific, meaning they may be similar. A check with Flora of China database yields slightly differing foliage characteristics given below. It is well known in the Plant Kingdom that a single species of plants with a widespread distribution can be variable in appearance. From the description below, I believe the one I showed in this post is M. chinensis.
Mesona chinensis (syn. M. procumbens) - Leaves narrowly or broadly ovate to subcircular, apex acute to obtuse, base cuneate to sometimes rounded . (Cruneate – a leaf with a wedge-shaped base with edges that form an angle less than 90 degrees, but greater than 45 degrees.)
Mesona parviflora (syn. M. palustris) - Leaves narrowly elliptic or ovate-lanceolate, apex short acuminate, base attenuate (Attenuate – a leaf with a tapering base with concave edges that form an angle less than 45 degrees.)
Leaf characteristics reference - http://www.northernontarioflora.ca/leaf_bases.cfm
The aerial parts of Mesona are picked and dried. During the drying process, leaves are allowed to oxidise where they also turn dark. To make the jelly, leaves are boiled in water with the addition of an alkaline substance such as potassium carbonate (ash from burned rice culms is also said to be used). The resultant solution is filtered through cloth and then cooled where it then solidifies to give the familiar gelatinous solid. Leaves of Mesona are believed to have ‘cooling’ properties in Chinese medicine .
In the garden, both species of Mesona make great groundcover plants for a herbal garden. Their sprawling and dense growing habit ensures any bare patches of ground are covered green and prevents soil eroson. Their leaf surfaces are shiny and the serrated foliage margins add interesting texture to the landscape. These plants produce numerous small flowers on erect spikes which are coloured blue – a rare floral colour in the tropics.