Range: Northern Australia north to Indochina, China, and Philippines
One of the most widespread species in the “indica complex” and perhaps second only in horticultural presence to D. finlaysoniana, this species is known from populations ranging from the northern half of Australia through Indonesia, the Philippines, Indochina, and southern China, and may perhaps share range with D. indica all the way up to Japan. It may be found growing anywhere with moist, open conditions, from flooded fields to rock seeps or ditches and even rice paddies. Large plants may exceed 30 cm tall, with a thick central stem supporting first erect and then falling horizontally oriented leaves, each filiform to linear-lanceolate with a distinct eglandular petiole section and up to 15 cm or more in length. Color is highly variable and may present as distinct forms alongside each other in habitat, from pure yellow-green in all parts to bearing scarlet tentacles, or even the entire plant flushing crimson. Helicoid inflorescences bear multiple blooms on distinct 1.5 cm pedicels, each flower up to 1.5 cm in diameter with ovular or egg-shaped to narrow obovate petals, often with semi-serrate tips, and colored any shade between pure white to pale or bright pink and even purple, with white, triangular stamens. Distinct traits of this species include petioles longer than that of D. indica, stems and leaf undersurfaces bearing few to many distinct red translucent glands and yellow mushroom-shaped glands, and the petiole upper surfaces bear y-shaped trichomes.
Cultivation: grow in any peat-sand soil mix, kept moist to even flooded and moderately humid with warm temperatures throughout the year. Sow seeds on soil surface, and grow in strong artificial light to full sun.
Lifespan and reproduction: annual. Reproduces through seeds only; stem cuttings may be possible to prolong plant life, but not for propagation.
If you happen to grow something labeled as D. indica, chances are it's probably actually a form of D. serpens. Among the sect. Arachnopus plants this is one of the most widespread and easiest to grow, performing leagues above D. finlaysoniana for me and capable of getting fairly large for a sundew. This does depend on the particular form though; some locales may only get a few centimeters tall, others may even push nearly half a meter. One thing they all share though: lanky, spreading serpentine leaves (hence the name, though ironic as the trait fits all species in the complex) and a penchant for blooming nonstop once they start.