Edible pennywort refers to several low-growing species, primarily those within the Hydrocotyle and Centella genera, which have been consumed across various global cultures. These plants have been utilized as a wild edible and vegetable for centuries, particularly in Asian and tropical regions. Well-known species include Centella asiatica (Gotu Kola or Asiatic Pennywort) and various Hydrocotyle species (commonly known as Dollarweed). Accurate identification is necessary before considering the culinary applications of this plant.
Visual Keys for Accurate Identification
The structure of the pennywort leaf is the most telling feature, characterized by its rounded, somewhat fleshy appearance, resembling a small coin or dollar. These leaves typically range from 5 to 10 centimeters across and exhibit a distinct, scalloped or slightly toothed margin. The leaf surface is generally smooth and light to medium green, though the exact size can vary.
A defining characteristic that differentiates many pennywort species is the attachment of the stem to the leaf blade. In many Hydrocotyle species, the slender petiole, or leaf stalk, attaches directly to the center of the leaf, creating a peltate or umbrella-like structure. The plant maintains a low-growing habit, spreading horizontally by sending out thin, creeping stolons that root at the nodes as they travel along the ground.
Centella asiatica shows a slight variation in leaf morphology, often presenting a more kidney-shaped or semicircular leaf. In this species, the stem typically attaches to the leaf at the indentation near the base, rather than the dead center. The stems themselves are thin and green to reddish-green, creating dense mats in wet, swampy, or marshy environments.
Crucial Distinctions from Toxic Look-alikes
Foraging for pennywort demands caution, as several poisonous plants, particularly those in the Apiaceae family, can be mistaken for it. The most dangerous imposters are Water Hemlock (Cicuta) and Poison Hemlock (Conium maculatum), both of which are acutely toxic. The primary safety measure involves recognizing that all edible pennywort species are low-growing, creeping plants with simple, round leaves, a trait that sharply contrasts with the taller, segmented look-alikes.
Water Hemlock and Poison Hemlock grow as tall, upright herbaceous perennials, reaching heights up to 3 meters, which is a significant difference from the ground-hugging pennywort. Their leaves are not round but are highly compound and lacy, divided into numerous small segments, giving them a fern-like appearance.
Water Hemlock exhibits a hollow stem that is chambered at the base and a root system often described as bundles of “dead man’s fingers.” Poison Hemlock is distinguished by its hollow, hairless stems that are characteristically marked with purple spots or streaks. Pennywort, in contrast, features slender, solid, and creeping stolons that root at the nodes.
Harvesting, Preparation, and Culinary Applications
Once a positive identification has been made, the process of harvesting and preparing edible pennywort can begin, focusing on sustainable collection and proper cleaning. The leaves and stems are the parts most commonly used, and they should be collected from clean, unpolluted water sources or soil, as the plant can absorb contaminants. To ensure the plant patch remains viable, only take a few leaves from each rosette, avoiding the removal of the entire plant.
After harvesting, the collected pennywort must be thoroughly washed to remove any mud, debris, or small insects, which is particularly important for plants growing in marshy conditions. Pennywort can be consumed fresh, dried, or cooked, offering versatility in the kitchen. The flavor profile is generally mild and slightly herbaceous, often described as having a slight bitterness or a subtle cucumber-like taste that becomes more pronounced in older leaves.
The fresh leaves are excellent when used raw, adding a slightly crisp texture to salads or mixed green dishes. A popular application in Southeast Asian cuisine is blending the leaves into a refreshing, slightly sweetened beverage known as Rau-ma or Pennywort Drink. For those who prefer a less bitter profile, the leaves can be lightly cooked, such as being stir-fried or incorporated into warm dishes like the Sri Lankan dish malluma, which mixes the greens with grated coconut. The culinary use of pennywort provides a nutritious, mineral-rich green.