BOTANY

Carol Brouwer, Ph.D.Horticulturist

http://www.flourishandbits.com

Botanical Studies

Taxonomy: classification and naming of plants

Morphology: study of plant structures

Physiology: study of plant functions

Genetics: study of heredity

TAXONOMYClassification of Plants

Classification Systems

2 million living things Organize into groups Improves 

communication Different groups for 

different reasons Habitat Physical similarities

Hierarchical Classification 

Taxonomy employs a hierarchical system of classification

Binomial System of Nomenclature

All species are named according to this system, which includes the authority for the name. Genus – noun Species – adjective  Spearmint:  Mentha spicata L.

History: Aristotle (384 BCE –322 BCE)

1st to classify organisms

All plant essays lost

History: Theophratus (370‐285 BCE)

Classified 500 species of plants on the basis of leaf characteristics.

History: Pedanius Dioscorides (40‐90 CE)

Materia Medica Five‐volumes in Greek One of the most 

influential herbal books in history

Remained in use until about CE 1600

History: Leonhart Fuchs (1501‐1566)

German physician  Baccalaureus Artium

(BA) 1524 ‐Magister Artium

(MA) 1524 ‐ doctor of 

medicine (MD)

History: Leonhart Fuchs (1501‐1566)

Fuchs’s History of Plants –1542

Offered botanical field days for the students

Demonstrated the use of medicinal plants in situ

Founded one of the first German botanical gardens

Plant and color Fuchsia are named for him by Charles Plumier

History: John Gerard (1545‐1611 or 12)

Gerard’s Herbal or General Histoire of Plantes ‐ 1597

English herbalist

History: Andrea Cesalpino (1519‐1603)

De plantis libri XVI ‐ 1583 Foundation for the 

morphology and physiology of plants 

First scientific classification of flowering plants

Used the fruit as the foundation of his botanical system

Made original, acute observations on flowers, fruits, and seeds before the discovery of the microscope

Genus Cesalpinia

History: Gaspard Bauhin (1560 – 1624 )

Pinax theatri botanici(1596)

Classified thousands of plants

Used a precursor to binomial nomenclature

Bauhinia sp. is named for him

History: John Ray (1627‐1705)

English naturalist Catalogus plantarum 626 plants listed Historia Plantarum Used system similar to 

Bauhin First to use term 

“species”

History: Carl von Linne’ (1707‐1778)

Classify all known plants and animals according to their genera 

Based on flower parts Used Latin phrases to 

reflect relationships  Placing one to many 

kinds of species in each genus

SystemaNaturae – 1735

Limited Latin phrase to 12 words

Abbreviated names to two parts (binomials).

Organized all known plants into 24 classes  based mainly on the 

number of stamens in flowers

Kingdoms over time

Linnaeus1735[56]

Haeckel1866[57]

Chatton1925[58]

Copeland1938[59]

Whittaker1969[60]

Woese et al.

1990[61]

Cavalier‐Smith1998[54]

2 kingdoms 3 kingdoms 2 empires 4 kingdoms 5 kingdoms 3 domains 6 kingdoms

(not treated) Protista

Prokaryota Monera MoneraBacteria

BacteriaArchaea

Eukaryota

Protoctista Protista

Eucarya

Protozoa

Chromista

Vegetabilia Plantae PlantaePlantae Plantae

Fungi Fungi

Animalia Animalia Animalia Animalia Animalia

Phylogenetic Tree of Life

Taxonomy Today

Lumpers phenetics – classification of organisms based on overall similarity

Linneaus’s classification based on resemblances between organisms (not evolutionary relationships)

Splitters Phylogenetics (systematics, cladograms) ‐ study of evolutionary relatedness among various groups of organisms

CLASSIFICATIONSConvenient groupings of plants

Plant DivisionsInformal group Division name Common name

No. of living species

Green algaeChlorophyta

green algae(chlorophytes)

3,800

Charophytagreen algae(desmids & charophytes)

4,000 ‐ 6,000

Bryophytes Marchantiophyta liverworts 6,000 ‐ 8,000

Anthocerotophyta hornworts 100 ‐ 200

Bryophyta mosses 12,000

Pteridophytes Lycopodiophyta club mosses 1,200

Pteridophytaferns, whisk ferns & horsetails

11,000

Seed plants Cycadophyta cycads 160

Ginkgophyta ginkgo 1

Pinophyta conifers 630

Gnetophyta gnetophytes 70

Magnoliophyta flowering plants 258,650

https://en.wikipedia.org/wiki/Plant

Plant Categories

Angiosperms (Magnoliophyta)

Monocots Dicots

Gymnosperms (Pinophyta) Conifers

Classes

Grasses Grass‐like plants Sedges Bullrushes Rushes

Forbs Herbaceous flowering 

plants

Woody plants

Grasses

Jointed, hollow stems Leaves in 2 rows and 

flattened Parallel venation Poaeaceae family Texas – 545 native 

species Monocots

Grass‐like Plants

Sometimes confused with grasses

Parallel venation No nodes Sedges  triangular stems Flattened leaves in 3 rows

Ruses  hollow or pithy Rounded and not branched Leaves near base of plant 

are round or flattened

Forbs

Broad‐leaf plants Herbaceous 

flowering plant that is not a graminoid (grasses, sedges and rushes). 

Not a tree, shrub Not always 

wildflowers Alfalfa Soybean

Woody Plants

Shrubs, sub‐shrubs and trees

Perennial Trees have a trunk ‘Brush’

Life Cycles

Annuals Biennials Perennials herbaceous woody

Seasonal Classification

Warm season Grow during frost‐free 

months Spring, summer, fall

Cool season  Tolerate frost Fall, winter, spring

MORPHOLOGY AND PHYSIOLOGYPlant Parts and Functions

Plant Parts & Functions

Sexual flower

Asexual leaves stems roots

Meristems

Primary Growth  apical 

meristem or apex

Secondary Growth Vascular 

cambium or cambium 

Roots

Primary Roots

Taproot Lateral 

Roots Fibrous

Roots

Knees Buttressed Aerial

Tuberous Roots

No Nodes Begonias Beets Dahlias Peonies

Root Structure

Dicot Root

Monocot Root

Monocot Root

Tree Roots

Most trees do not have tap roots

Roots grow beyond the edge of the branches

Most roots are in the top 3 feet of soil

Finer roots in top 12”.  Damaging roots may 

cause dieback

Stems

Support Vascular System Buds Leaf Bud Flower Bud Terminal Lateral/Axillary Adventitious

Leaves 

Stems

Support Vascular System Buds Leaf Bud Flower Bud Terminal Lateral/Axillary Adventitious

Leaves 

Primary Growth ‐Monocot

Primary Growth – dicot or gymnosperm

Secondary Growth ‐ dicots

periderm

phloem

cambium

xylem

ray

crushed cortex and past year’s phloem

32 1 pith

Section of a Yew (Taxus sp.)

Modified Stems ‐ Crowns & Stolon

Modified Stems

Bulb

Tuber

Rhizome

Bulb

Corm

Types of Leaves

Simple

Types of Leaves

Seed Leaves(Cotyledons)

Types of Leaves

Tendrils

Types of Leaves

Scale

Types of Leaves

Needles

Types of Leaves

Spines

Types of Leaves

Prickle

Types of Leaves

Bracts Poinsettia Bougainvillea Abelia

Types of Leaves

Thorns

Leaves

Absorb sunlight for photosynthesis

Leaf Layers

Leaf Cross‐section

Leaf Cross‐Section

Stomata

Leaf Venation

Reticulate

Leaf Venation

Pinnate

Leaf Venation

Palmate

Leaf Venation

Parallel

Leaf Types

Simple

Leaf Types

Pinnate Compound

Leaf Types

Double Pinnate Compound

Leaf Types

Palmate Compound

Leaf ShapesAcicularCordateDeltoidPeltateEllipticEnsiformFalcateHastateLanceolateLinearLigulateOblanceolateOblongObovateOrbicularOvalSagittateSpatulateSubulateTendril

Leaf MarginsCiliateCrenateCrenulateDentateDenticulateEntireIncisedLobedPalmately lobedPinnately lobedPinnatisectSerrateSerrulateSinuateSpinseUndulate

Leaf ApicesAcuminateAcuteApiculateAristateCaudateCirrhoseCleftCuspidateEmarginateMucronateMucronulateObcordateObtuseRetuseRoundedTruncate

Leaf BasesAcute

Attenuate

Auriculate

Cordate

Cuneate

Oblique

Rounded

Truncate

PubescenceGlabrousPiloseVillousStrigoseHispidHirsuleScabrousPuberulentTomentoseStellateStipitate GlandularSessile Glandular

Leave Arrangement 

Alternate 

Leave Arrangement 

Opposite

Leave Arrangement 

Whorled

Leaf Arrangement

Fasicled

Leaf Arrangement

Basal

Leaf Arrangement

Equitant

SEXUAL PLANT PARTS & FUNCTIONS

(Flowers)

Parts of the Flower

Types of Flowering Plants

Monoecious = 1 House Corn Pecan

Dioecious = 2 Houses Holly Junipers

Types of Flowering Plants

Monoecious = 1 House Corn Pecan

Dioecious = 2 Houses Holly Junipers

Flowers

Complete = Pistil, Stamen, Petal, Sepals

Incomplete = Missing One

Perfect = Pistil & Stamen

How Seeds Form

Pollination Pollen tube Fertilization

Types of Flowers

Solitary ‐ one flower per stem Inflorescence ‐ a cluster of flowers racemous ‐ indeterminate (flower from the bottom up)

Racemous Flowers

Spike ‐ flowers attached to peduncle ‐gladiolus

Racemous Flowers

Raceme ‐ individual flowers attached by tiny stems to the peduncle Bluebonnet

Racemous Flowers

Catkin  Mulberry birch

Racemous Flowers

Corymb  yarrow

Racemous Flowers

Umbel dill onion queen anne’s lace

Racemous Flowers

Head sunflower  daisy

Flower Types

cyme ‐ determinate ‐flower from the top down ‐ top florets open first dischasium cyme ‐

baby’s breath helicoid cyme ‐ freesia scorpioid ‐ tomato 

(alternate)

Types of Inflorescence

Fruit

Fruit consists of the fertilized and mature ovules (seeds) and the ovary wall.

Parts of the Fruit

seed

dry fruit(corn) fleshy fruit (peach)

exocarp

mesocarp

endocarp

pericarp

Types of Fruit

berry

pepo

pome

hesperidium

drupe

pod

aggregate

multiple

Parts of the Seed

testa (seed coat)

hilum

micropyle

dicot seed (bean)

plumule

epicotyl

cotyledon

hypocotyl

radicle

embryo

Bean Seed Germination

Water Light Heat Oxygen

Corn Seed Germination

PLANT PROCESSES

Photosynthesis

Produces food Stores Energy Occurs only in cells 

containing chloroplasts

Releases Oxygen Uses water Uses carbon dioxide Occurs in sunlight

Light Cycle (Photolysis, Hill Reaction)

Light reacts with pigments in the leaf causing the splitting of water molecules. 

Three products: Electrons from the 

hydrogen molecules

H+ ions ‐ used to form two separate energy storage molecules. 

Oxygen

Dark Cycle (Calvin Cycle)

Carbon dioxide molecules are transformed into sugars using the energy that was formed during the light reaction.

C3 ‐ efficient C4 ‐more efficient (grasses) CAM ‐most efficient (succulents)

Respiration

Uses food for plant energy Releases energy  Occurs in all cells Uses oxygen Produces water Produces carbon dioxide Occurs in darkness as well as light

Net Reaction

6 CO2 + 6H2O  C6H12O6 + 6 O2

light

carbon dioxide

water Carbohydrate(sugar)

oxygen

energy for growth (ATP)

Photosynthesis

Respiration

Transpiration

Process of water loss Occurs through the 

stomata Uses 90% of water taken 

up Necessary for cooling 

and mineral transport Depends on: temperature wind humidity

FACTORS AFFECTING PLANT GROWTH

Light

Quality Quantity Duration Necessary for photosynthesis

Light Quality

Light Quantity

Intensity Summer vs. Winter Shade vs. Sun Equator vs Arctic Indoors vs Outdoors

Light Duration

Photoperiod induces flowering, bud break etc.

Short Day = > 12 hours dark chrysanthemum, poinsettia

Long Day = < 12 hours dark California Poppy, beet, radish, lettuce

Day Neutral = doesn’t care

Temperature

Productivity  High Temperature  increased respiration, transpiration

Low Temperature  poor growth

Temperature

Flowering ‐ Mums, Christmas Cactus, Daffodils, Tulips

Chilling Hours Peaches, Apples

Winter Injury USDA Zone Map

Water

Photosynthesis Cohesion Theory Wilt (PWP) Managing Stress

Plant Nutrition

Nutrition vsFertilization

Macro = N, P, K, Mg, Ca, S

Micro = Fe, B, Zn, Cu, Mn, Mo, Cl, Co

Absorbed as ions pH Foliar Absorption

BOTANY

Carol Brouwer, Ph.D.Horticulturist