Regions: East India

A floating rosette that shades a tub and starves the algae — but a weed if it escapes.

A tiny creeping mat for the wet edge of a tub — the softest possible ground cover.

The wild ancestor of cultivated rice, still standing in eastern wetlands.

Half the country’s calories — and a bucket of it on a terrace teaches more than any book.

Flame-red reflexed petals on a climbing lily — the state flower of Tamil Nadu.

Pale crisp fruit that smells of rose water, on a small spreading evergreen.

The slender betel-nut palm of the wet coasts, grown in dense shaded gardens.

Small upright fruit on a woody perennial that crops for years in the hills.

Spokes of leaf on a green stem — the marginal plant that makes a tub read as a pond.

The world’s most stubborn weed, and an aromatic tuber used for centuries.