Oak
Reference: Plant perception
No limbs, no eyes, no nerves — and still responsive to light direction, colour, duration, gravity, touch and injury. The plant answer to every axis is a different answer, not an absent one.
Scored on every axis
Sensing without organs
Plants have no eyes and detect light in more dimensions than we assume. Phytochromes read the red-to-far-red ratio, which tells a plant whether it is being shaded by another plant — leaves absorb red and pass far-red, so a shifted ratio means competition rather than cloud, and the plant responds by growing taller. Cryptochromes and phototropins handle blue light and direction. Photoperiod sensing measures night length precisely enough to time flowering to the season.
Add gravity sensing in the root tip, touch responses, and volatile chemical signalling that neighbouring plants alter their defences in response to. None of it requires a nervous system, and calling it “seeing” or “communicating” overstates it — but calling the plant unresponsive is simply wrong.
Breathing and standing up
Gas exchange runs through stomata, adjustable pores mostly on the leaf underside, which open for carbon dioxide and close to limit water loss — the central trade of plant life, made continuously.
Support comes from lignin stiffening cellulose cell walls: not a skeleton in the animal sense but a structural material, laid down cell by cell, holding a canopy up for centuries. The tallest trees exceed a hundred metres on it.