Plants
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166 free Plants trivia questions with answers — nature quiz, new questions added Oct 2026.
50 free plants trivia questions with answers. Did you know that plants produce about 80% of the oxygen we breathe? Test your botanical knowledge with our comprehensive 166-question Plants quiz covering everything from photosynthesis to rare species. You'll learn surprising facts about the green world around you while challenging yourself against trivia questions that span beginner to expert levels.
30 of 166 questions with answers and explanations. Play the quiz
Q 01What pigment gives most plants their green color?
Chlorophyll
Chlorophyll looks green because it soaks up red and blue light for energy and reflects the green wavelengths it barely uses.
Q 02What gas do plants absorb from the atmosphere during photosynthesis?
Carbon dioxide
Carbon dioxide is the raw material of wood, which is about half carbon by weight; that is why van Helmont's potted tree could grow heavy in the 1600s while its soil barely lost weight.
Q 03In which part of a plant cell does photosynthesis primarily occur?
Chloroplast
Chloroplasts began as free-living cyanobacteria engulfed by an ancestral cell, which is why they still carry their own DNA and multiply by dividing in two.
Q 04What is the main product plants create through photosynthesis?
Glucose
Glucose rarely stays as glucose: the plant ships it around as sucrose, stores it as starch and strings it into cellulose, the stuff of cotton and wood.
Q 05What are the tiny pores on the surface of leaves called that allow gas exchange?
Stomata
Stomata are each flanked by two guard cells that swell with water to open the pore and go limp to shut it, which lets a thirsty plant seal its leaves.
Q 06What part of a flower produces pollen?
Anther
Anthers of tomatoes and blueberries hold their pollen tight, so bumblebees grip the flower and buzz their flight muscles to shake it loose, a trick now used in commercial greenhouses.
Q 07By what process do plants lose water vapour through their leaves, drawing more up from the roots?
Transpiration
Transpiration lifts water without a pump: as vapour escapes the leaves, each molecule tugs on the next, hauling an unbroken thread of water up from the roots.
Q 08What type of plant tissue transports water from roots to leaves?
Xylem
Xylem is what wood is made of: its water-carrying cells die as they mature, leaving the empty, stiffened tubes that both carry sap upward and hold the tree up.
Q 09What is the female reproductive part of a flower called?
Pistil
The pistil is named for the pestle it resembles; once its ovules are fertilised, its swollen base, the ovary, ripens into the fruit.
Q 10What is the point on a plant stem where a leaf attaches called?
Node
Node is also the botanist's word for a potato's 'eye': the tuber is a swollen stem, and each eye is a node whose bud can sprout a new plant.
Q 11What is the tallest species of tree in the world?
Coast redwood
Coast redwood holds the record through Hyperion, about 116 metres tall; the park has since closed the ground around it because visitors seeking it out were trampling its base.
Q 12What is the largest tree by volume in the world?
Giant sequoia
Giant sequoia cones can stay green and shut for twenty years; the heat of a fire dries them open, raining seed onto freshly cleared ground.
Q 13What makes a Venus flytrap's trap snap shut?
Two touches
Two touches in a row, within about twenty seconds, tell the trap that something alive is walking inside; it then counts several more before it starts to digest.
Q 21Which climbing plant's cone-like flowers give beer its bitter flavour?
Hops
Hops replaced 'gruit', the mix of bitter herbs that earlier brewers relied on, and they do more than flavour beer: they also help it keep.
Q 22Which insect is shipped across America in rented hives each February to pollinate California's almond orchards?
Honeybee
Honeybee hives are rented because the vast almond orchards need far more pollinating insects than live nearby; it is the biggest managed pollination event in the world.
Q 23What is a plant that completes its entire life cycle in one growing season called?
Annual
Annual plants live on only as seed: the field poppy dies each year, but its long-lived buried seeds sprout when the soil is turned, which is why poppies flare up in ploughed fields.
Q 14Which carnivorous plant uses a pitfall trap filled with digestive fluids?
Pitcher plant
Pitcher plants are not always killers: one mountain species feeds tree shrews at its lid and collects their droppings, which supply most of the nitrogen in its leaves.
Q 15What is the part of a seed that develops into the new plant?
Embryo
The embryo is a complete miniature plant held dry and dormant; when the seed soaks up water it swells, splits its coat and the embryo's root pushes out first.
Q 16White flour is milled from which starchy part of the wheat grain?
Endosperm
Endosperm is the grain's own food store for the sprouting plant; millers strip away the bran and the oily germ, which would turn flour rancid, and keep the starchy white core.
Q 17Monocots are named for having a single what?
Seed leaf
Seed leaf is the plain name for a cotyledon: monocots have one and dicots two, which is why a bean or peanut splits so neatly into halves.
Q 18What do we call trees that drop all their leaves each year, usually in autumn?
Deciduous
Deciduous trees such as oaks, maples and birches shed all their leaves in autumn to cut water loss in the cold or dry season; the word comes from Latin decidere, 'to fall off'.
Q 19What is the largest individual flower by diameter in the world?
Rafflesia arnoldii
Rafflesia arnoldii has no leaves, stem or roots of its own: it lives hidden inside a vine and shows itself only as a metre-wide bloom that reeks of rotting meat to draw flies.
Q 20What type of plant reproduces via spores rather than seeds?
Fern
Ferns shed dust-fine spores from the brown dots under their fronds: each dot is a cluster of spore cases, and a ring of cells around each case flings the spores into the air.
Q 24What ecological role do plants play as the base of most food chains?
Producers
Producers trap the sun's energy, but only about a tenth of it passes up each link of a food chain, which is why food chains are so short.
Q 25What is the symbiotic relationship between fungi and plant roots called?
Mycorrhiza
Mycorrhiza is a trade: the fungus's fine threads reach soil that roots cannot, bringing back water and phosphorus, and the plant pays with a share of the food it makes.
Q 26Which growing method, used for greenhouse lettuce and tomatoes, raises plants with their roots in nutrient-rich water instead of soil?
Hydroponics
Hydroponics was coined in 1937 from the Greek for water and toil, after its promoter William Gericke found his first choice of name, aquiculture, was already in use for raising aquatic life.
Q 27Cinnamon sticks are made from which part of a tree?
Inner bark
Inner bark is peeled from young shoots that sprout after the tree is cut back to a stump; as the strips dry they curl by themselves into the familiar quills.
Q 28What is the process of growing a new plant from a cutting of an existing plant?
Vegetative propagation
Vegetative propagation keeps a variety true: apple pips grow into something different from the parent, so every Granny Smith tree is a copy descended from one chance seedling found in 1868.
Q 29Which biome has the greatest diversity of plant species?
Tropical rainforest
Tropical rainforest grows on surprisingly poor soil: heavy rain leaches the nutrients away, so the forest lives on fast recycling of its own litter, and cleared plots are often farmed out within a few years.
Q 30Which common herb is a member of the mint family and is widely used in Italian cuisine?
Basil
Basil is the heart of Genoa's pesto, a sauce named for how it was made: 'pestare' is Italian for pounding, since the leaves were crushed by hand in a mortar.