Lactuca indica aka Indian Lettuce

Lactuca indica is also known as Indian lettuce. It belongs to the Asteraceae family. Its native range spans southeastern Siberia, Japan, and Malesia. Useful Tropical Plants lists more places in its range. These include Korea and northeastern India, plus Vietnam, Laos, and Thailand. It also lists eastern and southern China. Kew links this plant with temperate climates. Useful Tropical Plants says it grows in the moist tropics. These accounts give it a broad range across Asia.

The plant grows upright from a taproot. Its leaves form a rosette at the plant's base. A stem grows above them, with few side branches. Useful Tropical Plants gives its height as about 4 feet [1.2 metres]. The sources differ on how long it lives. Kew calls it biennial. Useful Tropical Plants calls it perennial. The account for this species says insects pollinate it. Its photo captions say wind blows the ripe seeds away.

The account says this species grows best in sun. It gives 22–34°C as the best range for daytime warmth. It gives a wider range of tolerance, from 10–40°C. It says the plant prefers 1,500–2,500 millimetres of rain each year. It can also cope with 1,000–3,000 millimetres each year. In the tropics, people grow it up to 6,562 feet [2,000 metres]. These climate figures do not show how much frost it can take. The supplied evidence gives no lowest winter temperature for garden use.

People gather Indian lettuce from the wild for food and medicine. Growers in several Asian countries also raise it for its leaves. These include Malaysia, Indonesia, the Philippines, Taiwan, and Japan. People sometimes sell the leaves at local food markets. This supports its use as a leaf crop. The species evidence does not say when to harvest it. Nor does it show a tested use for garden display. Facts about named forms alone do not show care needs for the whole species.

Read the safety evidence with care. Useful Tropical Plants reports no specific finding of toxicity for this species. It warns that some related lettuces have compounds with narcotic effects. This does not prove that Indian lettuce has the same risk. Its use as food does not prove all uses are safe. The supplied species evidence names no pests or diseases. It gives no firm basis to rate its safety for pets.