TREES, LEAVES, FLOWER

smithsonian

TREES, LEAVES,

FLOWERS & SEEDS

A VISUAL ENCYCLOPEDIA OF THE PLANT KINGDOM

WRITTEN BY DR. SARAH JOSE
CONSULTANT DR. CHRIS CLENNETT

CONTENTS FOREWORD 6

DK DELHI THE WORLD 8
Senior Editors Anita Kakar, Bharti Bedi, Rupa Rao OF PLANTS
10
Senior Art Editor Shreya Anand The plant kingdom 12
Editorial team Arpita Dasgupta, Bipasha Roy What is a plant? 14
Art Editors Baibhav Parida, Debjyoti Mukherjee How do roots work? 16
Assistant Art Editors Sifat Fatima, Sanya Jain What is a stem? 18
Living bridges 20
Jacket Designer Tanya Mehrotra How do seeds grow? 22
Jackets Editorial Coordinator Priyanka Sharma Seed shapes 24
Scattering seeds 26
Senior DTP Designer Harish Aggarwal Spreading without seeds 28
DTP Designers Jaypal Chauhan, Ashok Kumar, Vijay Kandwal, The life cycle of a plant 30
What is a leaf ? 32
Mohammad Rizwan, Vikram Singh, Rakesh Kumar Simple leaves 34
Senior Picture Researcher Sumedha Chopra Compound leaves 36
Picture Researchers Aditya Katyal, Vishal Ghavri Plants with patterns 38
Picture Research Manager Taiyaba Khatoon Symmetrical swirls 40
Self-defense 42
Managing Jackets Editor Saloni Singh Plants and nitrogen
Pre-production Manager Balwant Singh
NONFLOWERING 44
Production Manager Pankaj Sharma PLANTS
Managing Editor Kingshuk Ghoshal 46
Managing Art Editor Govind Mittal Nonflowering plants 48
Ancient plants 50
DK LONDON What is a fern? 52
Senior Editor Ashwin Khurana Fern fronds 54
Senior Art Editor Rachael Grady Dinosaur diet 56
US Editor Jennette ElNaggar What is a conifer cone? 58
US Executive Editor Lori Cates Hand Pines and needles 60
Jacket Designer Surabhi Wadhwa-Gandhi Conifer cones
Jacket Editor Emma Dawson
Jacket Design Development Manager Sophia MTT
Producer, Pre-production Andy Hilliard
Senior Producers Jude Crozier, Mary Slater
Managing Editor Francesca Baines
Managing Art Editor Philip Letsu
Publisher Andrew Macintyre

Art Director Karen Self
Associate Publishing Director Liz Wheeler

Publishing Director Jonathan Metcalf
First American Edition, 2019

Published in the United States by DK Publishing
1450 Broadway, Suite 801, New York, NY 10018
Copyright © 2019 Dorling Kindersley Limited
DK, a Division of Penguin Random House LLC

19 20 21 22 23 10 9 8 7 6 5 4 3 2 1
001–310149–Sept/2019
All rights reserved.

Without limiting the rights under the copyright reserved above, no
part of this publication may be reproduced, stored in or introduced
into a retrieval system, or transmitted, in any form, or by any means

(electronic, mechanical, photocopying, recording, or otherwise),
without the prior written permission of the copyright owner.
Published in Great Britain by Dorling Kindersley Limited

A catalog record for this book is available from the Library of Congress.
ISBN 978-1-4654-8242-6

DK books are available at special discounts when purchased
in bulk for sales promotions, premiums, fund-raising, or educational

use. For details, contact: DK Publishing Special Markets,
1450 Broadway, Suite 801, New York, NY 10018
[email protected]
Printed and bound in China
A WORLD OF IDEAS:
SEE ALL THERE IS TO KNOW

www.dk.com

Established in 1846, the Smithsonian—the world’s largest museum
and research complex—includes 19 museums and galleries and
the National Zoological Park. The Smithsonian is a renowned
research center, dedicated to public education, national service,

and scholarship in the arts, sciences, and natural history. Smithsonian
Gardens, an accredited museum and Public Garden, engages people
with plants and gardens, informs on the roles both play in our cultural

and natural worlds, and inspires appreciation and stewardship of
living and archival collections and horticultural artifacts.

FLOWERING Going underground 136
PLANTS Soft fruits 138
62 Volcanic vineyard 140
What is a flower?
Flower forms 64 Stone fruits 142
Pollinators 66 Juicy fruits 144
Looks familiar Tropical fruits 146
River of blossom 68 Magnificent melons 148
A garden of roses 70 A bit nutty 150
Crazy for daisies 72 Eat your greens! 152
Ingenious orchids 74 Peas and beans 154
Blossoms and bulbs 76 All squashed up! 156
What’s that smell? 78 Pumpkin boat race 158
Living in water 80 Bulbs, stems, and stalks 160
Along the river 82
Flooded forest 84
What is a cactus? 86
Cool cacti 88
Desert survivors 90 LIVING WITH 162
Desert bloom 92 PLANTS
Meat-eating plants
Poisonous plants 94
Parasitic plants 96 Plants and people
Mountain life 98 The spices of life 164
Creepers and climbers 166
What is a tree? 100 Helpful herbs 168
Types of trees 102 Plant products 170
Barking up the tree 104 Shrinking forest 172
Standing tall 106 Natural beauty 174
Blossom time 108 Plants of the world 176
Living on air 110 Plant science 178
Strangler fig 112 Space garden 180
The forest floor 114
Bonsai 116
What is a grass? 118
Types of grasses 120
Grasses and grains 122
Rice terraces 124 GLOSSARY 182
Fruit or vegetable? 126 PLANT INDEX 184
128 INDEX 188
130 ACKNOWLEDGMENTS 192

132
134

Austrian pine Forget

-me-not

Star fruit

FOREWORD

Plants are essential for life. They make our This amalgamation of disciplines is what first
planet’s atmosphere breathable, their decaying attracted me to the profession and has held my
bodies create the soil under our feet, and they interest for more than 40 years. This volume
transform light energy into consumable nutrients brought me back to Hort Studies 101, with each
that keep us alive. They also inspire artists; think chapter examining different plants, their parts,
of Georgia O’Keeffe’s Poppies, Claude Monet’s and how they interact with the world around
Water Lilies, and Vincent van Gogh’s Sunflowers. them. Thankfully, the photographs used reveal
details—ranging from tangled roots to distinctive
Trees, Leaves, Flowers & Seeds combines the seed and flower shapes—that surpass the old
art and science of plants, revealing complex transparency sheets used by my professors.
botanical details in beautiful photographs and
simple graphics. While previewing this book, Similar to Trees, Leaves, Flowers & Seeds,
I wondered where it was when I was a child Smithsonian Gardens combines art and science
interested in learning more about plants. in its many diverse garden and landscape
exhibits. While their beauty is often what initially
It reminded me why I began my career in attracts visitors, the science they embody
horticulture. At its most basic level, horticulture showcases our living collections and provides
is the science and art of growing plants.

rnflower ropical pitcher p il
T lant
Thai bas

Co

Ech

everia

Angel wings Dwarf pomegranate

depths of engagement with our audiences. Throughout this book, you will find scale boxes that
Our gardens are delightful examples of show the sizes of plants compared to either a child,
performative art. They change every season, a school bus, or a human hand.
indeed every day, of their existence. Smithsonian
Gardens’ staff horticulturists and gardeners are Child = 4 3⁄4 ft
extraordinarily knowledgeable when it comes to (1.45 m) tall
plant science, yet so much of their work evolves
into genuine artistry thanks to their natural skill School bus = 36 ft
in combining living collections. (11 m) wide

Perhaps the fascinating information and Hand = 6 in
engaging photographs in Trees, Leaves, Flowers (16 cm) long
& Seeds will launch an inquisitive child’s journey
into the mesmerizing world of plants.

Cynthia Brown

Smithsonian Gardens Education and Collections Manager

Dragon fruit

Holly Radicchio



THE WORLD
OF PLANTS

The world of plants Nonflowering plants

These are the oldest plants and include ferns
and mosses, which reproduce using spores.
Conifers, which produce naked (not enclosed)

seeds, also belong to this group.

Liverworts Mosses Hornworts Lycopods

ommon liverwort mooth hornwort
Stif clubmoss
S
Grasses
C
Star moss Little bluestem

The plant Daisies
kingdom
Figaro dahlia
There are around 400,000 different types of plants,
and botanists—scientists specializing in plants—
discover new ones all the time. Hundreds of millions
of years ago, the first plants were small and did
not flower. Over time, the process of evolution
has created a fantastic range of plants, from simple
ferns to stunning cherry blossoms and spiky cacti.
To bring order to this incredible variety, botanists
divide up plants into nonflowering and flowering
plants. Within these categories, there are many
10 species, and some of them are shown here.

PLANT KINGDOM

Flowering plants

Angiosperms, or flowering plants, make
up more than 90 percent of all plants.
They produce seeds that are protected
by a hard casing.

Angiosperms
The plant kingdomFernsGymnosperms

Lo
S
oft tree fern dgepole pine
Lupine
Monocots
Dicots
Monocots have just one seed leaf, which
grows into a new plant. They often have Dicots have two seed leaves, which appear
together when a new plant starts to grow.
long, narrow leaves. Grasses, orchids,
and palms are examples of monocots. They mostly have broad leaves. Dicots
include daisies, roses, cacti, and legumes.
Orchids
Palms

Vanda Coconut palm Legumes

Roses Cacti

Chinese rose Old man of the Andes Snow pea

11

The world of plants What is Flower ❯ This colorful part of the plant
a plant?
contains the male and female cells that
Plants come in all shapes and sizes—from are responsible for producing seeds.
tiny green mosses to giant trees—but almost
all plants contain a green pigment called
chlorophyll. This chemical harnesses
the energy of sunlight to make the food
(a sugar called glucose) that the plant
needs to grow. As part of this process,
called photosynthesis, plants take carbon
dioxide gas from the air and turn it into
food, while releasing oxygen, which all
animals need to breathe.

Tendril ❯ This plant has a special

stem, called a tendril, which
wraps around nearby objects,

helping support the plant.

Not a plant

Lichens Corals Algae Fungi
A lichen is made up of algae Corals are tiny, underwater animals Many algae are green, like Unlike plants, fungi get their
and fungi living together. The with hard skeletons. To grow, they plants, but do not have true food from the soil, or from
algae help make food, while depend on algae in their tissues to roots, stems, and leaves. Algae other plants and animals on

the fungi provide shade. make energy from sunlight. can live only in water. which they grow.

12

Stem ❯ The stem supports Leaf ❯ This is the power

the plant. It can be short or station of a plant. Leaves use
tall, woody or nonwoody. sunlight to make the energy
the plant needs to grow.
Cucumber
plant

Fruit ❯ A fruit contains

the plant’s seeds, protecting
them from harm. Colorful
fruits attract animals to eat
them and then spread the
seeds in their droppings.

Flowering plant Root ❯ Plants use their roots

This cucumber plant uses flowers to to anchor themselves to the
reproduce and make seeds for new ground. Roots also draw water
plants. However, not all plants have and nutrients from the soil to
flowers—simple plants, such as mosses keep the plant alive.
and conifers, reproduce in other ways.
It is sometimes difficult to tell what is
a plant and what is not—seaweed and
fungi, for example, are not plants.

How do Leaf ❯ A plant’s leaves use the energy
roots
work? from sunlight to make sugar. Water
is drawn up through the roots and
Most plants have roots, which anchor sugary sap moves down from the
the plant in the ground. Roots soak up leaves, powering the plant’s growth.
vital water from the soil, along with the
dissolved minerals that the plant uses to Burdock
grow. Grasses have tufts of fibrous roots, root
but most other plants grow at least one
taproot, which then sprouts smaller lateral
(side) roots that spread outward.

Taproot ❯ As a seed starts to grow, one

or more strong roots push down into the
soil. This is the plant’s taproot, and it grows
only at its tip, forcing soil particles aside
with a tough root cap as it grows deeper
into the ground.

Lateral root ❯ These spindly roots branch out

from the main taproots to form a complex,
tangled network of roots.

Root hair ❯ Tiny root hairs sprout from

just above the growing tip of each
root. They grow between soil particles
and absorb the water and minerals
that the plant needs to grow.

Root hairs grow from
the root’s skin cells
(seen here in pink).

Types of roots

Aerial Some plants, typically in tropical forests, Buttress Many tropical rain forest trees are Pneumatophore Rooted in waterlogged, Stilt Mangroves growing on muddy tidal
grow in the treetops with roots that cling to supported by roots that spread out partly airless mud, these mangrove trees grow in seashores are swept by waves at high tide.
above the ground. This is because most swampy, subtropical brackish (salty) water. Many mangrove trees have stiltlike roots
the tree bark for support. The American pearl rain forest soil is not very deep and these Some have roots that grow upwards into that arch down from their trunks to help
laceleaf grows roots that hang in the moist air
surface roots help anchor the tree. the air to gather oxygen. support them in the moving water.
to absorb essential water.

What is
a stem?

A stem is like a plant’s backbone, holding it up and
connecting its roots, leaves, flowers, and fruits. It raises
the leaves toward the sunlight so they can make food,
which is then transported by the stem to the rest of
the plant. It also carries water and nutrients up from the
roots. There are many different types of stems, from soft,
green stems to hard tree trunks.

Creeper stem ❯ Young English

ivy stems are soft and flexible,
with tiny anchoring roots to
help it climb. As the plant

grows, the stems grow thicker
and harder, sending out side

shoots to explore new spaces.

Sugarcane

Tough stem ❯ This tall grass supports English ivy

itself with a tough stem. Special tissues
running down the stem transport the sugar

made in its leaves to other parts of the
plant. Sugarcane stems hold a lot of

sugar, which can be harvested and dried
to produce the sugar that we eat.

Woody stem ❯ Trunks and branches are woody stems, Types of stems

which are stiff and strong to provide support for tall There are many types of stem. Woody stems
trees. The live tissue (cambium) is protected by an outer contain two layers of tissue—one transports
covering of dead bark. These stems expand by producing water, and the other food in the form of sugar. In
new layers of woody tissue each year—the growth rings nonwoody stems, these tissues are combined into
tubes. Woody stems are protected by thickened
that can be seen in cut tree trunks. bark, while nonwoody stems are covered by a thin,
protective tissue layer.
Soft stem ❯ The nonwoody
Tissue
stems of many smaller plants transporting
are soft and green. They support
the plant, while transporting water
water and nutrients.
Tissue
transporting

sugar

Corhkaszcerel w Soft, Nonwoody stem
spongy layer

Thin outer
layer

Tissue Woody stem
transporting

sugar

Tissue
transporting

water

Core of
woody stem

Tough,
strong bark

Sun rose Sweet sap suckers

Small bugs called aphids puncture
stems to suck out the sweet, nutrient-
rich liquid transported inside it. These
insects don’t usually kill the plant but
can often slow down its growth and carry
diseases that might harm it.

LIVING BRIDGES The state of Meghalaya in northeast India is one of the
wettest regions in the world, with almost 39 ft (12 m) of
rainfall each year. The rains flood the rivers, making travel difficult, but the local Khasi Tribe came
up with a clever way to stay connected with other villages. Using the roots of the rubber fig tree,
they built strong, living bridges that can hold up to 50 people at once.

This type of bridge is made by twisting the aerial roots 15–20 years to build a living bridge, which can grow to more
(roots that grow above ground) of rubber fig trees around than 164 ft (50 m) in length. The strongest living bridges are
temporary bridges made of bamboo or tree trunks, which more than 100 years old, with some believed to be more
then rot away over time. Once the tree roots reach the than 500 years old. This double-decker bridge in Cherrapunji
other side of the river, they are planted into the ground is more than 180 years old, and the local people are now
so they can grow thicker and stronger. It can take about adding a third level to it to attract more tourists.

The world of plants How do The right conditions
seeds
grow? Seeds need ideal conditions—warmth, air,
and water—to germinate. Some need
Plants are rooted to the spot, so to reproduce and darkness to sense they are properly
spread, flowering plants make seeds from which buried. Others need light to know they
new plants grow. A seed contains a tiny young are not buried too deep.
plant called an embryo, which lies dormant
(inactive) until it senses the perfect conditions Young shoot ❯ Next, a young
to germinate and grow into a new plant.
shoot emerges from the seed,
growing upward until it breaks
out of the soil. It quickly
begins to make food
using sunlight.

Germination ❯ A seed lies First root ❯ Most seeds begin

dormant until it detects germination by sending a root
moisture and warmth. It then downward into the soil. The root
absorbs water from the soil, absorbs water and nutrients
and the seed springs to life, in a from the soil and passes them
process known as germination. on to the developing shoot.

Inside a seed

A seed is a perfectly packaged baby plant, called an embryo,
protected by a hard outer coat. The embryo has a root and a
shoot, and the first true leaves. It also has a food store for
the embryo in “seed leaves.”

Seed leaves ❯ The first leaf, A hard seed coat The first true leaves
protects the embryo will grow from this
or pair of leaves, in a flowering growing shoot point.
plant often looks very different from damage.
to the true leaves the seedling
will grow later. This is because The root of the
the seed leaves were part of the embryo grows first.
embryo that lived inside the seed.

Seed leaves take up
much of the space
inside the seed.

Inside a seed

One leaf or two?

The seed case There are two main types of flowering Two broad seed
still clings to plants—monocots and dicots—named leaves grow out
the young plant for the number of seed leaves they of a dicot seed.
as it emerges have. Monocot seeds contain one seed
from the ground. leaf, while dicot seeds have two.

New leaves will A single seed leaf
form at the top emerges from the
tip of the shoot.
of the stem.

Corn seed Germinating Bean Germinating
(monocot) monocot seed (dicot) dicot seed

The root has fine Early germination
hairs to help it absorb

even more water.

Sometimes seeds germinate before they have parted from
their parent plant. This early germination may take the form of
shoots growing on the outside of a fruit, as on this strawberry.
In other fruits, shoots may even burst through the fruit wall
from the seeds held inside.

Germinating seed

Seed shapes

Tiny, kidney-shaped Magnified view Almost all the grain is Hundreds of
seeds are less than filled with starchy tissue. seedlike fruits
1 mm in length. are produced
per flower head.

This curved, bumpy Sunflower Bright red
fruit is filled by a wings grow
single, curved seed. up to 4 in
(10 cm) long.
Pot
Poppy Barley marigold fegd

Coriander Small, dry fruits Haaiprity-olnea
are used as a spice.

Odd-shaped Beet Love in Black seeds have
seeds are a puff a heart-shaped
white patch.
about 2–3 mm Yellow kernels Wide, thin wings
across. are rich in vitamins. Wrinkled, oval help this seed glide for
seeds are known
Coffee as stones or pits. hundreds of feet.

Peach

Corn

Two coffee seeds, or Avocado
beans, are produced
in each red fruit of
the coffee plant.

A juicy, red Kiaat
coat surrounds
This round seed grows A circular, papery
each seed. up to 2½ in (6.5 cm) long. wing surrounds this
spiky seed pod.
Pomegranate

A seed is a small package that protects a The giant coco de mer seed is able to hold
young plant and contains all the nutrients a lot of nutrients so that the new plant has
the plant will need to germinate. Although enough energy to grow out of its mother’s
all seeds do the same job, they come in a shadow. The poppy has another survival
wide range of shapes and sizes, to help strategy—rather than one big seed, it produces
each one survive in its particular tens of thousands of tiny seeds to maximize
environment and spread without being its chances. The spiky coats of the horse
22 eaten by hungry animals. chestnut seed and the kiaat seed pod

Coco de mer These massive seeds
are the largest and heaviest

in the world, weighing up
to 39 ½ lb (18 kg) each.

These glossy
seeds are protected
by a spiky shell.

Horse
chestnut

Flat, circular seeds are
a good source of protein.

Lentils

Javan cucumber
deter hungry animals, while other seeds,
such as those of the avocado and peach,
are too hard for most plant eaters to munch.
Sometimes, what we think of as seeds are, in
fact, fruits with seeds inside, including those of
the sunflower, coriander, and pot marigold.

The world of plants Blackberry Dandelion

Juicy berries are
eaten by harvest
mice, which pass the
seeds in their poo.

Scattering
seeds

When shaken, lotus
seeds fall from the
dried seed pod and
into the lake or pond in
which the plant grows.

Lotus

Spiky burdock seeds can
grow up to 1 in (3 cm) across.

Burdock Between 90 and 110 feathery
bristles radiate outward to

form a parachute on every seed.

Plants are anchored by roots and can’t move from one
place to another. If they dropped their seeds where they
stood, the new plants would be in competition for nutrients
and sunlight. So plants have developed many ways to make
sure their seeds scatter far and wide to take advantage of new
places in which to grow. They use exploding seed pods,
animals, the wind, or even water to spread their seeds.

Single-winged Up to 200 seeds
seeds spin like can be produced
helicopter rotors. by a single flower.

Norway maple Alder

Coconut fruits When the flower head thiMstillek
are salt-proof and dries out, it releases seeds
float on seawater. with silvery parachutes.

Woody scales of the
female catkin (flower spike)
open up to release seeds.

Cuipo seeds
have five wings,
which make them
spin as they fall.

Cuipo plants
sprout as soon as

their seeds land
on the forest floor.

Coconut

Acorns are essential Cu ipo
fall food for many

animals, from squirrels
and woodpeckers to
deer, pigs, and bears.

Acorn

Wind and water carry seeds farthest. Dandelion When animals eat fruit, the undigested seeds 25
and milk thistle seeds have parachutes that inside the fruit pass through their droppings.
carry them on the breeze, while maple and Burdock seeds are covered in hooks that get
cuipo seeds catch the wind as they fall from caught in animal fur and transported. Squirrels
the tree canopy. Amazingly, coconut seeds can bury hundreds of acorns each fall to eat in
travel hundreds of miles on ocean currents. winter. The ones they forget about germinate
Animals are also important seed spreaders. into new oak trees.

Spreading
without seeds

Tiny plantlets with roots
form along the fleshy leaves.
The world of plants Iris
Mint

Underground Spreading underground
stems can send out stems are partially visible
new shoots around through a thin layer of soil.
the mother plant.
Plantlet

Stems grow
from the base
of the old tree.

Mother of thousa Beech

nds

Each leaf can
produce dozens
of tiny plantlets.

Some plants have evolved ways to Plants such as mint, strawberry, and bamboo
spread quickly over an area without send out long stems, either just below or on top
seeds. To do this, they make perfect of the soil, which can put down roots and grow
copies of themselves using modified into whole new plants. The creeping underground
stems, forming underground storage stems, or rhizomes, of some irises also send up
organs, or growing baby plants on the new plants as they spread. Other plants, such as
26 margins of their leaves. sweet potatoes, produce underground storage

Spider p These stems grow Parent plant sends
roots and then out horizontal stems
along the soil.
leaves to become
independent plants. New bamboo shoots
can grow up to 35 in
(90 cm) in a day.

Plantlets grow BambooStrawberry
on dangling stems.lant
STEM RUNNERS

The strawberry plant produces long stems called
runners that run along or just under the soil. New
strawberry plants grow at the knots, or nodes, on the
runners, quickly colonizing an area with good soil.

Runners lay down roots
before new plants can grow.

New shoots Parent plant New plant
grow from marks
called “eyes.” Fleshy root
tubers are popular
Sweet potato starchy foods.

Underground
stems spread

quickly, sending
up new shoots.

organs called tubers. If harsh weather are touching the ground. The
kills off their leaves, new plants can mother of thousands plant takes
regrow from the starchy tuber, using this even further, producing tiny
it for food. Spider plants grow new plantlets, complete with roots,
leaves at the tips of their hanging along the edges of its leaves. These
flower stems, which quickly grow eventually drop off the mother
roots when they detect that they plant and grow around its base.

The world of plants The life 8 The fruit
cycle of develops and
a plant
Seeds lie dormant ripens. New seeds
Flowering plants may have a (inactive) waiting
life span of just months, or many 1 are dispersed by the
years. A poppy will germinate,
flower, set seed, and die within for the right conditions wind, and the cycle
a year and is known as an annual
plant. Other flowering plants live to germinate. starts again.
for several years, building up the
food reserves they need and storing 2 Germination begins
it. These are called perennial plants. when there is enough
The harsher the climate, the longer
it can take for a plant to complete water, warmth, and light for
its life cycle.
the seeds to sprout their first

root and then a shoot.

Late bloomer 3 Seedlings begin to
produce leaves to gather
High in the cold Andes
Mountains of South America, light and more roots to absorb
the queen of the Andes plant
grows very slowly. It takes over water from the soil to help
80 years to bloom and grows a
spike nearly 30 ft (10 m) tall, them grow.
with up to 30,000 flowers,
dwarfing the surrounding 4 Flower buds develop. In plants
plants. After shedding that flower every year (annuals)
millions of seeds, it dies.
such as poppies, the bud can form
28
within a few weeks of germination.

Po ppy

7 As soon as a flower
is pollinated, it

sheds its petals. Seeds

form inside the fruit.

5 Protected within the green sepals 6 Once the petals open
(leaf-shaped, and sometimes hairy, up, insects, such as

structures at the base of a flower), the bud

grows colorful petals. When the flower is bees, are attracted to the

ready to open, the petals burst out. sweet nectar inside and

pollinate the flower.

29

What is Small netted veins ❯ Networks of
a leaf?
tiny veins connect the green tissues
Leaves are usually flat, green structures that of the leaf to the main vein inside
grow from plant stems. Although they come the midrib and the stem beyond.
in many shapes and sizes, almost all of them
The world of plants capture sunlight and produce food for the
plant. Leaves get their green color from
a pigment called chlorophyll that uses
sunlight to produce food from the plant
in a process called photosynthesis.

Stomata ❯ Tiny pores on the

underside of the leaf, called
stomata, open during the day to take

in carbon dioxide but close at night
to avoid losing too much water.

ple leaf
Underside of ap
Blade ❯ The flat part of the leaf is
Petiole ❯ This is the stiff stalk connecting
called the leaf blade. It is the green
the leaf to the plant stem. In some plants, tissue that absorbs sunlight to make
these stalks can help leaves move and
the sugar the plant needs to grow.
follow the sun in order to absorb more light.
30

Midrib ❯ Running along the center of the Photosynthesis

leaf, this thickened area contains the central Plants make their own food in a process called
vein. It also provides support to the leaf to photosynthesis. Their leaves contain a light-
prevent it from bending and breaking. harvesting pigment called chlorophyll. This green
chemical uses the sun’s energy to convert carbon
dioxide from the air and water from the soil into
food (in the form of sugars) and oxygen.

Sunlight provides
the energy needed
for photosynthesis.

Carbon dioxide Oxygen is
enters the leaf. released as a

by-product.

Apple leaf Sugar is produced in
green leaf tissues.
Vein ❯ Plant veins have two types of tubes
Water and minerals are
running through them. One type, called absorbed through the
xylem, carries water from the roots to the roots and transported
shoots. The other type, known as phloem, up the stem.
transports sugars around the plant.
Fall leaves

As fall approaches, the green pigment chlorophyll is
replaced at a slower rate than it is used up. The
reduced chlorophyll levels mean other leaf pigments,
including orange-yellow ones, become more
obvious. At the same time, plants start producing
red-purple pigments. These changes result in the
beautiful fall displays of leaf colors.

Maple leaves in fall

The world of plants Simple
leaves

Young leaves have five Dandelion
sharp points, while older
Spear- leaves are rounder. These jagged Amazonian water lily
shaped leaves contain
Einvgylish a bitter milky
sap called latex.

Sugar maple leaves
turn red before falling

in autumn.

Divided Palm-shaped Circular

Leaves develop large Sugar maple
holes as the plant ages,
and can grow up to
35 in (90 cm) long.

Swiss-c

heese plant

Veins grow from Oval-shaped
the stalk at the
center of the leaf.

Spiky edges protect
the leaves from

grazing animals.

Heart-shaped Nasturtium Circular Holly

A leaf typically consists of a flat surface Simple leaves come in many shapes and sizes,
called a blade, which carries a network of and those best suited to their habitat are the most
veins. These veins support the leaves and likely to thrive. In wet rain forest conditions plants
transport the water and minerals to them have big leaves, while plants in drier locations
from the rest of the plant. A simple leaf usually have small leaves. Some plants, such as
32 has a single, undivided blade. English ivy and ginkgo, change their leaf shape

Ginkgo Fan-shaped Arrow-
shaped

Veins branch out
like a fan instead of
forming a network.

These giant leaves grow
up to 9 ft (3 m) across.

Engli
sh oak

Divided English oak leaves, Eucalyptus
which can grow up to 4 in
(10 cm) long, turn brown
and fall off in the autumn.

Jagged edges
are more common
in leaves from
colder countries.

Waxy leaves repel
water, so rainwater
flows quickly off this
rain forest plant.

h
ear
Silver birc ElephantT’shin, bladelike
leaves are common Linear
This leaf contains a in grass plants.
Triangular toxic oil to avoid being

eaten by predators. Lance-shaped Wheat

as they grow and get more access to sunlight. as possible. Although the reasons 33
The Swiss-cheese plant and elephant’s ear remain unclear, scientists believe the
grow in rain forests so have waxy, pointy leaves jagged leaf edges of sugar maple and
to help rainwater run off. Another rain forest plant, silver birch may help keep them slightly
the Amazonian water lily, has giant leaves that warmer than smooth edges would, allowing
spread across lakes to capture as much sunlight the plants to grow faster in cool spring weather.

Compound
leaves

Sensitive plant

Leaflets fold shut
in about three
seconds if touched.
The world of plants
TamarindFeathery leaves
turn a golden yellow

in the fall.

Divided Stinking toe
twice

Two Shiny green leaflets
leaflets look like a cow’s toes, but
this plant gets its name
from its stinky fruit.

Lupine Arranged

like a closed
fan when young;

Rounded lupine the lupine’s leaves Oval leaflets
leaves have up fold up at
to 17 leaflets. unfold as
night and open
it grows. Divided into an during the day.

Multiple leaflets even number of leaflets

A compound leaf is one that is divided into A compound leaf has separate leaflets with
two or more parts called leaflets. These less individual surface area than a simple leaf.
leaflets grow either along the stalk like In a dry region, this helps the plant to reduce
a feather or from a single point like a fan. the amount of water lost through evaporation.
Compound leaves come in a wide range Compound leaves, like that of the lupine, flutter
34 of shapes and sizes. less in windy conditions than simple leaves,

Honey locust Veins from
the main leaf
stalk run through

each leaflet.

Divided into an odd
number of leaflets

Four heart-shaped
leaflets grow
from a single stalk.

Five leaflets

Horse chestnut

Four-leaved Four
pink sorrel leaflets

Flat leaf stalk
looks like a second
leaf below the true leaf.

Silve r fern Silvery undersides Leaf stalk (bottom)
of the leaves give this looks like true leaf
fern its name. Pomelo
LONGEST LEAF

A whitish, V-shaped Raffia palm 82 ft (25 m) long
band is typical in leaves grow Raffia palm leaf
a whopping
white clover leaflets. 82 ft (25 m)
long—more
than twice
as long as a
school bus.

Divided twice White
clover Three leaflets

making them less likely to break off. Having Some compound leaves grow very quickly, 35
compound leaves can also help the plants avoid which helps trees, such as the honey locust,
being eaten. Leaflets of the sensitive plant harness as much sunlight as possible before losing
quickly fold up if touched by hungry animals, their leaves in the fall. The pomelo has a rare type
while tamarind leaflets close up at night to of compound leaf with a flat stalk that looks like
appear smaller and less tasty to plant eaters. a second leaf, which also helps capture sunlight.

The world of plants Plants with
patterns

The lighter patches cannot
make energy from sunlight,

slowing the growth of this plant.

These light pink
flowers have deeper
blotches of color on the
upper two petals.

Geranium Areas over the veins Butterfly agave
do not make the red
coloring, or pigment, White marks look
so they look white. like damage done by
a leaf-mining insect.

Angel wings

White spots mimic water
damage to protect the leaf

against being eaten.

The color-breaking
stripes are caused by
a viral infection.

o lily
p
Flaming Tuli
Multicolored plants—also known as Virginia waterleaf
variegated plants—are popular with
gardeners but are rare in nature. It’s the Gardeners have cultivated plants with
green parts of the leaves that trap sunlight patterned leaves and flowers because
to harvest its energy, so white or yellow they look beautiful. The outlined leaves
36 patches slow plant growth down. of the butterfly agave and holly and
the attractive flowers of geranium,
flamingo lily, and dahlia are very rare

onia Beg White patches do
Rose not have the ability
The silvery patches can to make color.
produce food, too, helping Prayer pl
ant
this plant grow.
Begonias
These spiky leaves produce seeds
are very hardy. The so small they

holly plant can grow up look like
to 50 ft (15 m) in height.
dust.

Holly Prayer plant leaves
come in many patterns,
from mosaic to striped.

Purple-blue flowers
are marked with white
spots of different sizes
and resemble a starry

night sky.

Dahlia Only the tips of Petunia
this flower make
the pink pigment.

in wild plants. In the 17th century, striped Virginia waterleaf are among the few 37
tulip flowers were very fashionable in the plants that have naturally patterned leaves.
Netherlands and sold for huge amounts of Both have white spots on their leaves,
money. It was later found that the delicate which make them appear damaged and
markings on the tulips were actually the less appetizing. This greatly reduces the
result of a viral infection. Angel wings and chance of insects eating their leaves.

SYMMETRICAL SWIRLS Twirl a sunflower around in your
fingers and the pattern at the center
of the flower head looks the same from every side. This is because the sunflower head is radially
symmetrical—the florets form two sets of spirals starting at the same point somewhere in the center
of the flower, before turning in opposite directions, one clockwise and the other counterclockwise.

Radial symmetry appears throughout the plant world, from in nature is because this is the best way to pack the most
daisies to pine cones. The spirals follow a pattern known as flowers, leaves, or seeds into a tight space. A sunflower head
the Fibonacci sequence, named after the Italian mathematician is made up of many tiny florets—the dark rods in the picture
who discovered it. In this sequence, each number is the sum are opened florets, while those in the center are unopened
of the previous two. The pattern starts 1, 1, 2, 3, 5, 8, 13, 21, ones. Each new floret grows at an angle to the previous one,
and so on. The reason why Fibonacci numbers are common leaving no gaps and maximizing its exposure to pollinators.

The world of plants Self- Animals can run from their predators, but
defense plants have no way of escaping hungry
plant eaters. Instead, they have developed
Needlelike crystals some clever ways of making themselves
line the blue agave’s look and taste as unappealing or dangerous
as possible, encouraging animals to look
leaves, making them an elsewhere for a meal. Plant defenses range
unpleasant mouthful. from spiky thorns to toxic chemicals.

Spiky leaf edges protect
these succulent leaves.

Camel Silver-gray crystals

thorn Tea leaves contain tannin, Blue agave
a bitter-tasting chemical that
deters animals from eating them.

Fully developed
thorns may
grow up to 2 1⁄4 in

(6 cm) long.

Spines on the stem Tea
protect the plant from
hungry animals.

These woolly
leaves are difficult
for insects to munch.

These swollen parts
provide hollow homes
for ants that help
ward off predators,
protecting the plant.

40 Ant fern
Thistle
Lamb’s ear

To deter predators, some plants, including blue agave, produce nasty-tasting or irritating
the camel thorn, produce sharp branches chemicals to put off any animal that takes a
called thorns, while others, such as gorse, bite. The spots on passion flower leaves are
make sharp leaves known as spines. a clever defense called mimicry—the
Prickles are extensions of the stems of plant’s leaves pretend to be infested
plants such as roses. Another plant defense by butterfly eggs, which deters
strategy is the use of chemicals. Plants, real butterflies from looking
such as tea, common milkweed, and for a “healthy” leaf.

Thorns grow up Passion flower
to 3 in (7 cm) long.

The gummy Leaf spots resemble
white sap of this yellow butterfly eggs.
flowering plant is
Common toxic to many Whistling Ants live inside Small
milkweed plant-eating thorn acacia these swollen thorns,
mammals. protecting the plant birds nest
The stiff spines that cover from herbivores. in spiky
the plant can be up to gorse bushes to
2½ in (6.5 cm) long. Gorse
protect themselves

from predators.

Stems and leaves Buds contain yellow
are covered in tiny flowers with a
stinging hairs. coconut scent.

Stinngeitntlge Rose

Needlelike Downward-
hairs can inject pointing prickles

a painful mix grow on the
of chemicals. stems of roses to
deter predators
from climbing up.

Stinging hairs 41

The world of plants Plants and
nitrogen

Plants use the energy of sunlight to turn
carbon dioxide and water into the sugars
they need to help them grow. To do this,
they also need proteins that contain
nitrogen. Although this vital gas makes
up two-thirds of the air we breathe,
plants cannot absorb nitrogen from the
air. Instead, they rely on tiny organisms
in the soil to make nitrates both from
the nitrogen in the air and from the
decaying remains of living things.

Nitrogen cycle 1 Nitrogen gas enters the soil
from the air. Lightning can
All plants, animals, and other living things contain
nitrogen. When they die, their remains are broken also change nitrogen gas into nitrates.
down by fungi and bacteria. This eventually forms
nitrates, which plants can use to make proteins that
can be eaten by animals. Nitrogen is recycled
continuously between the air, soil, and living things
in this way—a process called the nitrogen cycle.

2 Some bacteria in the soil 3 Plants absorb nitrates
can change nitrogen gas into
dissolved in the water that
ammonia, which can be turned their roots soak up from the soil.
They use the nitrates to make the
into nitrates. Similar bacteria, proteins essential for growth.

called nitrogen-fixing bacteria, live Nitrogen-fixing bacteria

in the roots of plants such as peas.

Nitrogen deficiency Plants and nitrogen

If a plant is short of nitrogen, it
cannot make enough protein and
does not grow properly. It also cannot
make enough of the chlorophyll
that makes its leaves green, and
the edges of its leaves turn pale
or even yellow.

Nitrogen-deficient grape leaf

4 Animals, such as cows, eat plants.
They digest the plant proteins to make

the animal proteins their bodies need.

5 Animal waste, such as

dung and urine, returns
nitrogen-containing compounds
that can be turned into nitrates
to the soil.

7 Some kinds of
bacteria in the soil

turn nitrates back into

nitrogen gas, which is

6 Some fungi and released into the air.
bacteria living in

the soil feed on animal

waste, or on the decaying

remains of dead animals

and plants. They break

down nitrogen-containing

compounds to release

Decomposing fungi nitrates into the soil.



NONFLOWERING
PLANTS

Nonflowering plants Nonflowering
plants

The most ancient land plants on Earth are the nonflowering plants
that evolved hundreds of millions of years ago. The earliest were
simple plants such as liverworts, mosses, and hornworts, which grow
in damp places to avoid drying out. Ferns are more complex but still
have to live in moist environments. Instead of producing seeds, almost
all nonflowering plants reproduce using tiny spores, which are carried
away by wind or water. Only the gymnosperms, a group of nonflowering
plants that includes conifers, produce seed-bearing cones instead.

Moss life cycle Food factory ❯ The green

A moss’s spore capsule releases spores into the wind. leaflike part of this moss,
When they land, they grow into leafy shoots with tiny sex called the gametophyte,
organs. When it rains, male sperm cells are able to reach produces food using energy
eggs and fertilize them. Each fertilized egg grows a new from sunlight. It does not
shoot, and the cycle continues. contain veins to transport
water and nutrients, but its
Spore capsule surface is so thin that these
simply soak through.
Male Female

1. Scattering spores 2. Sex organs develop

Raindrops allow male sperm

cells to swim over to the eggs.

Spore-producing
shoot

4. Spore capsule grows 3. Fertilization

Capsule ❯ A spore-producing capsule forms at Nonflowering plants

the tip of each threadlike sporophyte. When the Liverwort
spores are mature, the lid of the capsule breaks The first land
off to reveal an opening, through which the plants were the tiny
spores are released. Every capsule contains liverworts, which
hundreds of thousands of tiny spores, which appeared around
are carried off on the wind. 470 million years ago.
Around 9,000 liverwort
Brown sporophytes do not species exist today.
make their own food, relying on
the green gametophyte instead. Moss
Mosses grow in fluffy
Capillary thread moss clumps, often in shady
areas. Although they
may look similar,
12,000 different
types of mosses exist
around the world.

Hornwort
These humidity-
loving plants,
which are named
for their horn-shaped
sporophytes, can
even grow under water.

Club moss
The spore-producing
brown spikes of club
mosses are held on
mosslike stems, but
unlike mosses, the
green parts are
the sporophytes.

Horsetails
Horsetails have thin,
hairlike leaves that
run up their stems
like a bottlebrush,
and produce spores
in conelike structures
at the stem tip.

Sporophyte ❯ The spore-

producing, columnlike structure
rising from the green body of
the moss is a sporophyte.

It starts to grow when a female
egg cell is fertilized by a
male sperm cell.

47

Ancient The first animals lived in a world filled with
plants plants, but this vegetation looked different to
what we see around us today. The earliest
dinosaurs would not have seen flowers, and
the plant eaters would have chewed mosses
and horsetails instead of grasses. Many of
these ancient plants have disappeared, but
some continue to thrive today.
Nonflowering plants
woGolidttemroisnsgCommon tamarisk mossStar-shaped shootsSpore-producing
range from a yellow-green stems grow upright,
to a reddish brown color. allowing the spores to fly
over a greater distance.

These feathery
shoots look like
tiny fern fronds.

Forest star moss

Twisted
moss

Mosses absorb This tiny, leafy
water and nutrients liverwort grows
from rain and dust.
on damp soil.

Marsh
clubmoss

Glossy shoots Common
give this plant kettlewort
its name.

The first land plants appeared around the same complex, leaflike shoots, like those of the Ancient plants
time as the first insects. The earliest liverworts, modern tamarisk moss and the glittering
relatives of the common kettlewort and wood moss. Without veins to carry water
common liverwort, evolved about 470 million and nutrients from the soil to the shoots, these
years ago. They did not have roots, stems, or plants remain small. However, club mosses and
flowers but lived in damp places and simply horsetails, such as the marsh clubmoss, fir
absorbed water through their surface. Later came clubmoss, and meadow horsetail, have veins
hornworts and mosses, many of which had more running up their stems and so grow taller.

Spongelike moss HEALING MOSS
can store huge
Sphagnum moss is absorbent and very acidic,
amounts of water. so it prevents the growth of bacteria and fungi.
During World War I (1914–1918), bandages
um were sometimes wrapped around sphagnum
Common haircap Sphagn moss and used as dressings for soldiers. This
This unusually tall stopped their wounds from becoming infected
Scientists moss can grow up and helped them heal faster.
to 15 3⁄4 in (40 cm).
study the Dressing made of
sphagnum moss
common liverwort
to learn how Sphagnum bandage roll

plants These tiny upright
evolved. stems look like
little conifers.

The young plants Common
growing inside these liverwort

cups are splashed Each capsule
out by raindrops. produces thousands

hMoresaedtoaw of tiny spores.

Cuplike structure Velvmetofsesat

Spore-producing
cones grow at the
tips of fertile stems.
her- Fir clubmoss
il

Frond ❯ Fern leaves are called fronds. Male fern

Nonflowering plants These are usually divided into smaller
sections, which increases the leaf ’s
surface area so it can capture more
sunlight. Fronds not only carry out
photosynthesis, using the energy
from sunlight to make food
for the fern, but they are also
important for reproduction.

Pinna ❯ Each small segment Fiddlehead ❯ New

of a fern frond growing fronds develop as
from the central stalk, or tightly curled spirals
rachis, is called a pinna. called fiddleheads, which
unfurl as the leaf grows.
What is
a fern? Root ❯ The roots of ferns

Ferns are nonflowering plants that are very similar to those of
do not produce seeds. Instead, they flowering plants. They absorb
reproduce using tiny spores, which water and nutrients from the
are carried on the wind. Fern leaves soil and help anchor the fern
are known as fronds, and they grow into the ground.
from underground stems. Spores are
50 made on the underside of fronds.