A Comprehensive Botanical, Ecological, and Conservation Study
Centella asiatica, widely known as Thankuni, Indian Pennywort, or Gotu Kola, is a creeping perennial herb of exceptional biological and ecological importance. Recognized for its distinctive morphology and adaptability to moist environments, this plant occupies a unique niche in wetland and semi-wetland ecosystems across tropical and subtropical regions. Beyond its traditional familiarity in rural landscapes, Centella asiatica represents a key species for understanding ground-layer vegetation dynamics, soil stabilization, and microhabitat formation.
In eastern India and the Sundarbans deltaic region, Thankuni is a familiar component of damp fields, pond edges, and village commons. Its ability to thrive in fluctuating moisture regimes, coupled with its vegetative propagation strategy, allows it to persist even under moderate ecological disturbance. This article presents an in-depth, research-oriented exploration of Centella asiatica, covering its taxonomy, morphology, habitat preferences, global distribution, ecological role, and conservation considerations, with particular emphasis on its presence in the Sundarbans region.
Taxonomy & Classification
Systematic Position
Centella asiatica belongs to the family Apiaceae, a family characterized by herbaceous plants with compound inflorescences and aromatic properties. Unlike many erect members of the family, Centella exhibits a prostrate growth form, highlighting the morphological diversity within Apiaceae.
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Apiales
Family: Apiaceae
Genus: Centella
Species:Centella asiatica (L.) Urb.
The species epithet asiatica reflects its early recognition from Asian regions, although its present distribution is nearly pantropical.
Morphology & Field Identification
Growth Habit
Centella asiatica is a low-growing, stoloniferous perennial herb. It spreads horizontally through creeping stems that root at the nodes, forming dense mats over moist ground. This growth habit enables rapid colonization and effective ground coverage.
Stem and Stolons
The stems are slender, green to reddish, and glabrous, running close to the soil surface. Nodes along the stem give rise to adventitious roots, anchoring the plant securely while facilitating vegetative reproduction.
Leaves
Leaves are simple, orbicular to reniform, with crenate margins and long petioles arising from the nodes. The leaf blade typically measures 2–6 centimeters in diameter. The venation is palmately radiating, a useful diagnostic feature in field identification.
Flowers
Flowers are small, inconspicuous, and borne in simple umbels arising from the leaf axils. Each umbel usually contains three to five flowers, which are white, pinkish, or light purple in color. Flowering occurs intermittently throughout the year under favorable moisture conditions.
Fruits and Seeds
The fruit is a small, laterally compressed schizocarp that splits into two mericarps upon maturity. Seeds are minute and primarily dispersed by water movement, contributing to the species’ affinity for wet habitats.
Habitat & Distribution
General Habitat
Centella asiatica is strongly associated with moist to wet environments. It commonly occurs in paddy fields, pond margins, irrigation channels, damp grasslands, and shaded forest clearings. The species favors habitats with consistent soil moisture but avoids prolonged deep inundation.
Soil Preferences
The plant grows best in loamy to clayey soils rich in organic matter. Slightly acidic to neutral soil conditions favor vigorous growth. Its tolerance to periodic flooding allows survival in seasonally waterlogged areas.
Global Range
Centella asiatica exhibits a broad pantropical distribution. It is native to South and Southeast Asia but is now found across Africa, Australia, the Pacific Islands, and parts of the Americas. Its global spread has been facilitated by water dispersal, agricultural activities, and intentional cultivation.
In many regions, the species has become naturalized beyond its native range, forming stable populations in wetland and agricultural landscapes.
Preferred Habitat
Moisture Regime
Consistent soil moisture is the most critical requirement for Centella asiatica. While it tolerates short dry spells, prolonged drought severely limits growth and survival.
Light Conditions
The species thrives under partial shade to full sunlight. Shaded conditions often result in larger, softer leaves, whereas plants in open sunlight develop more compact growth forms.
Occurrence
Across the Indian subcontinent, Centella asiatica is widely distributed in rural and peri-urban landscapes. It commonly appears in agricultural fields, village wetlands, roadside ditches, and fallow lands during the monsoon and post-monsoon seasons.
The plant often forms mixed communities with other hydrophilic herbs, contributing to low-growing wetland vegetation layers.
Preferred Habitat in the Sundarbans Region
Deltaic Freshwater Zones
In the Sundarbans, Centella asiatica is primarily found in freshwater-influenced zones such as inland villages, freshwater ponds, canals, and agricultural fields. It is absent from core mangrove forests due to high salinity and tidal inundation.
Seasonal Dynamics
Monsoon rainfall significantly enhances population expansion in the Sundarbans periphery. During the dry season, populations retreat to shaded, moisture-retaining microhabitats.
Wetland herbs like Thankuni form the green carpet of village landscapes in the delta. Experience these living ecosystems through a well-designed Sundarban Tour Package that blends nature and culture.
Ecological Role
Soil Stabilization
The creeping growth habit and dense root network of Centella asiatica help bind surface soil, reducing erosion along pond edges and irrigated fields. This function is particularly valuable in flood-prone deltaic landscapes.
Microhabitat Formation
Dense mats of Thankuni create humid microenvironments that support invertebrates, soil microbes, and other small organisms. These microhabitats contribute to overall ecosystem productivity.
Primary Productivity
As a fast-growing herb, Centella asiatica contributes significantly to ground-level primary productivity in wetland ecosystems, supporting nutrient cycling.
Habitat Alteration
Drainage of wetlands, conversion of agricultural land, and excessive use of agrochemicals pose challenges to Centella asiatica populations. Reduced freshwater availability directly impacts its growth and reproductive success.
In the Sundarbans, increasing soil salinity and embankment construction may restrict suitable habitats in certain areas.
Conservation Efforts
Conservation Status
Centella asiatica is not globally threatened due to its wide distribution and adaptability. However, localized declines may occur where wetland habitats are degraded.
Habitat-Based Conservation
Protecting freshwater wetlands, maintaining traditional agricultural practices, and minimizing chemical runoff are essential for sustaining healthy populations.
For travelers interested in freshwater biodiversity alongside mangroves, a customized Sundarban Private Tour offers deeper ecological interpretation.
Did You Know?
Thankuni spreads more effectively through vegetative growth than through seeds.
The plant can regenerate rapidly after flooding events.
Its leaf shape resembles a small kidney, aiding quick identification.
Centella mats help maintain soil moisture during dry periods.
