Ferns, pines and flowering plants

Pteridophyta (ferns) (pteron = feather, after their feathery leaves) have true roots, stems and leaves, and vascular tissue: pipes for transport.

• Xylem carries water.
• Phloem carries food.

But they still need water to reproduce, and they make no seeds.

Cut a stem across and compare: in a fern, the pipes form one central strand, xylem wrapped in phloem; in a sunflower, separate bundles sit in a ring.

Gymnosperms (pines, cycads) (gymnos = naked, spermos = seed) suit cold, dry places. Their needle-like or scale-like leaves lose little water. They make seeds, which protect the baby plant and store its food, and they need no water for fertilisation. But the seeds are not inside a fruit: they sit uncovered on cones. Many homes have a pine cone from a hill station; that is where the seeds sat.

Angiosperms (flowering plants) (angeion = vessel, a container) keep their seeds inside fruits. Eat an apple or a mango, and the seeds are inside. They have the most complex bodies. Flowers attract pollinators and fruits help spread seeds, so they can live almost anywhere. They are the most varied plant group.

The big picture: from algae to flowering plants, plants evolved transport pipes, then seeds, then flowers and fruits: each new feature solved a problem of living on land.

An Indian treasure. *Hortus Malabaricus*, written in the 17th century by Hendrik van Rheede with the Indian herbalist Itty Achudan and other local experts, describes hundreds of plants of Kerala and their medicinal uses. It was one of the earliest scientific books on Indian plants.