Botany
O.S.U.E.MasterGardener
MahoningCounty
Classof2017
BillSnyder
March14,2017
PlantSciences
Agriculture-studyofplantsinrelaEontofield
cropproducEon.
Agronomy-scienceofcropmanagementand
includesthestudyofsoils.
HorEculture-scienceofgrowingfruits,
vegetables,flowers,andotherornamentalplants.
Botany-scienceinvolvingthestudyofallphases
ofplantlifeandgrowth.
DivisionsofBotany
PlantTaxonomy-classificaEonandnaming
PlantAnatomy-structure
PlantMorphology-originandfuncEonofplantparts
PlantPhysiology-processesofplants.
PlantPathology-diseasesofplants
PlantEcologyandGeography-relaEonshipsof
plantsinbio-communiEesandphysicaldistribuEon
PlantClassificaEon
Teminology
PlantClassificaEon
BasedonWoodyorHerbaceous
Lilac
Peony
AWoodyplantisaperennialtree Herbaceousperennialplantshave
orshrub.Thestemremainsabove stemsthatdiebacktotheground
groundduringthewinter.
eachyear.
PlantClassificaEon
BasedonLifeCycle(Herbaceous)
Annuals
Biennials
Perennials
PlantClassificaEon
BasedonLifeCycle
Annualscompleteafulllifecycleinoneyear.
Marigolds
Snapdragons
Zinnias
NoteforLawns:
Summerannualweedscompletegrowingseasonduringspringandsummer.
e.g.crabgrassandspurge(SpringpreemergenceapplicaEon)
Winterannualweedscompletegrowingseasonduringfallandwinter.
e.g.annualbluegrassandhenbit(FallpreemergenceapplicaEon)
PlantClassificaEon
BasedonLifeCycle
Biennialscompleteafulllifecycleintwoyears.
SweetWilliam
SwissChard
Hollyhocks
PlantClassificaEon
BasedonLifeCycle
Perennialsliveformanyyears,formingflowersandseedseachyear.
Theabove-groundpartsmaydiebackinwinter,butre-growinSpring.
Hosta
Dahlia
HerbaceousPerennials
Forsythia
WoodyPerennial
PlantClassificaEon
BasedonWinterLeafandNeedleLoss
WoodyPerennialareclassifiedaseitherDeciduousorEvergreen.
Deciduous–lose
leavesorneedlesinwinter
Maple
Evergreen–keep
leavesorneedlesyear-around
LarchSpruce
Rhododendron
PlantClassificaEon
BasedonSeedProtecEon
SeedPlantsareclassifiedaseitherangiospermsorgymnosperms.
Gymnospermsarewoody,perennial,andwithfewexcepEons
evergreen.Theirleavesmaybefern-like,scale-like,strap-shaped,or
needleshaped.Thisgroupisrepresentedprimarilybyconebearing
trees(conifers)andpalm-likeplants.Membersofthisgroupare
cypress,pine,cedarsandyews.
Angiospermsareaclassofplantsinwhichthematureseedis
surroundedbyfruit.Angiospermsaretreesthathavebroadleaves
thatusuallychangecoloranddieeveryautumn(e.g.oaks,maples
anddogwoods).Someangiospermsholdtheirleavesduringwinter
(e.g.rhododendron).
EvergreenAngiosperms(rhododendron)
EvergreenAngiosperms(rhododendron)
DeciduousGymnosperms
Europeanlarch
Larixdecidua
Europeanlarch
Larixdecidua
PlantClassificaEon
BasedonPlantGrowthPaZerns
(angiospermsclassified)
Cotyledons=seedleaves
Monocotyledonousplants
Dicotyledonousplants
Monocots
Dicots
PlantClassificaEon
BasedonPlantGrowthPaZerns
PlantCell
PlantStructure/Anatomy
Roots
RootTypes
RootStructure
(celldifferenEaEon)
(cellgrowth)
(celldivision)
Xylem-carrywaterdissolvedminerals.
Phloem-carryfoodsuchassugars.
cellsbecomespecificEssuessuchas
epidermis,cortex,orvascularEssue.
undifferenEated
cells
cellsincreaseinsizethroughfoodand
waterabsorpEon.Astheygrow,theypush
therootthroughthesoil.
areaofcelldivisionandgrowth
RootCrossSecEon
RootGrowth
Thefollowingfactorsareimportantinrootgrowth:
Rootsinwater-saturatedsoildonotgrowwellandulEmatelymay
dieduetolackofoxygen.
Rootspenetratemuchdeeperinloose,well-drainedsoilthanin
heavy,poorlydrainedsoil.
Adense,compactedsoillayercanrestrictorterminaterootgrowth
InaddiEontogrowingdownward,rootsgrowlaterallyandocen
extendwellbeyondaplant'sdripline.
Keepthisextensiverootsysteminmindwhendisturbingthesoil
aroundexisEngtreesandshrubs.
RootHairwithMycelia
MycorrhizaisasymbioEcassociaEonbetween
afungusandtherootsofavascularplant.
Mycorrhizae
ThefungimyceliaconnecttotheEnytreeroothairs
anddelivernutrientstothetreesroots.Sincefungiare
excepEonallygoodatbreakingdowncomplex
moleculesintosimpleones,theyincreasethetrees
abilitytogathernutrients.
FortreesthisisespeciallycriEcalduringthefirstfew
yearsoflife.Whentheseedlingtreefirstgets
established,itsneedforwaterandnutrientsisocen
greaterthanitsEnyrootsystemcanproduce
GarlicMustard
Garlicmustardisabiennial,
growingitsfirstyearasa
seedlingandfloweringthe
subsequentyear.Itmostocen
growsintheforestunderstoryor
alongforestedgesbutisalso
abletoinvadeundisturbedforest
habitats.Ittolerateslowlight
levelsandisadaptedtotake
advantageofdisturbedhabitats
suchastrails,roadsidesand
areaswheretreeshavebeen
removed.
Garlicmustardreproducesonlybyseed.Mostseedsgerminate
withinthefirstorsecondyearacerbeingproducedbutcan
remainviableinthesoilseedbankforuptofiveyears.
Individualplantsproduceupupto7,900seedsandgrowto3to4
feetinheight.
GarlicMustardproduceschemicalswhichsuppressmycorrhizal
fungithatmostplants,includingnaEveforesttrees,requirefor
opEmumgrowth.Becauseseedscontainedinthesoilcan
germinateuptofiveyearsacerbeingproduced,long-term
removalisrequiredtodepletetheseedbankandallow
recoveryofmycorrhizae.
RootsasFood
SweetPotatoesareswollentuberousroots.
Carrots,ParsnipsandRadishesareelongatedtaproots.
PlantStructure/Anatomy
Stems
Stems
Terminology
Shoot:Ayoungstem(1yearoldorless)withleaves.
Twig:Ayoungstem(1yearoldorless)thatisinthe
dormantwinterstage(hasnoleaves).
Branch:Astemthatismorethan1yearold,
typicallywithlateralstemsradiaEngfromit.
Trunk:Awoodyplant’smainstem.
StemStructure
StemsasVascularTissue
Stemssupportbudsandleavesandserveasconduitsfor
carryingwater,minerals,andfood(productof
photosynthesis).
ThevascularsysteminsidethestemformsaconEnuouspathway
fromtheroot,throughthestem,andfinallytotheleaves.
Waterandfoodproductsmovethroughthisvascularsystem.
StemStructure
StemPlumbing
Xylemtubescarrywaterdissolvedminerals.
Phloemtubescarryfoodsuchassugars.
CambiumisalayerofacEvelydividingcells
thatseparatesthexylemandphloem,
producingnewxylemandphloemcells.
TreeTrunkBasics
Bark
Sugars /
Carbohydrates flow
down and up the
tree through the
Phloem
Cambium cells
divide to become
Phloem and Xylem
Phloem
Cambium
Xylem
Water and nutrients
flow up the tree
through the Xylem
GraphicbyJoeBoggs,OSUExtension
RingPorousTrees
Water is transported
only through the
current annual ring
Bark
Phloem
Cambium
Ash
AshTrees
BlackLocust
Elm
Hickory
Honeylocust
Oak
Xylem
GraphicbyJoeBoggs,OSUExtension
DiffusePorousTrees
Water is transported
through several
annual rings
Birch
Beech
Dogwood
Maple
Poplar
Sycamore
Spruces,Pines,
Firs,Hemlock
MapleTrees
Bark
Phloem
Cambium
Xylem
GraphicbyJoeBoggs,OSUExtension
StemStructure
MonocotStem(disconEnuous)
WoodyDicotStem(conEnuous)
Resistantto2,4-DHerbicide
HerbaceousDicotStem(conEnuous)
Killedby2,4-DHerbicide
Auxin(PlantGrowthHormone)
2,4-DHerbicide
StemStructure
NoVascularCambium
MonocotStem(disconEnuous)
WoodyDicotStem(conEnuous)
Resistantto2,4-DHerbicide
HerbaceousDicotStem(conEnuous)
Killedby2,4-DHerbicide
StemNodes
Anodeisanareaonastem
ofgreatcellularacEvityand
growth,wheresmallbuds
developintoleaves,stems,
orflowers.
StemModificaEons
AboveGround:Crowns,SpursandStolons(runners)
Stolonsarefleshyorsemiwoody,elongated,
horizontalstemsthatocenliealongthesoil
surface.Strawberryrunnersarestolons.
Crowns(e.g.strawberries)arecompressed
stemswithleavesandflowersonshort
internodes.
Spurareshort,stubby,sidestemsthatarise
fromamainstem.Theyarethefruit-bearing
stemsonpear,apple,andcherrytrees.
StemModificaEons
BelowGround:Bulbs,Corms,RhizomesandTubers
DaffodilBulbs
Tunicatebulbs(e.g.,daffodilsandtulips)
haveathin,paperycovering,which
actuallyisamodifiedleaf.Thecovering
helpsprotectthebulbfromdamage
duringdiggingandfromdryingoutonce
itisoutofthesoil.
LilyBulb
Nontunicatebulbs(e.g.,lilies)do
nothavethispaperycovering.They
areverysuscepEbletodamageand
dryingout.
StemModificaEons
BelowGround:Bulbs,Corms,RhizomesandTubers
CrocusCorm
Cormslikebulbsarecomposedof
stemEssue,buttheyarenotthesame.
Cormsareshapedlikebulbs,butdo
notcontainfleshyscales.Acormisa
solid,swollenstemwithdry,scale-like
leaves.Gladiolusandcrocusesproduce
corms.
Whenacorm
iscutinhalfit
issolid,but
whenatrue
bulbiscutin
halfitismade
upoflayers.
GladiolusCorm
StemModificaEons
BelowGround:Bulbs,Corms,RhizomesandTubers
IrisRhizomes
Rhizomesresemblestolons
becausetheygrow
horizontallyfromplantto
plant,butundergroundin
thecaseofrhizomes.
Inpotatotubers,the“eyes”
areactuallythestem’s
nodes,andeacheye
containsaclusterofbuds.
PotatoTubers
StemsasFood
Potatotubersarefleshy
undergroundstems.
Gingerrhizomesare
fleshystems.
PlantStructure/Anatomy
Leaves
LeafStructure
Terminology
IfpeOoleisabsent,
theleafbladeis
sessileorstalkless.
Dependingon
condiEons,
axillarybudscan
developinto
stemsorleaves.
node
or
leafaxil
AbsorbsunlightforsugarproducEonthroughPhotosynthesis
LeafStructure
Protectagainst
dehydraOon
anddisease
LeafBladeLayers
waxycuOn
Amount
increaseswith
increasedlight
intensity–preventsunscald
LeafStructure
LeafBladeCuEnLayer
LeafStructure
LeafBladeLayers
palisademesophyll
palisadeparenchyma
groundEssue
photosynthesis
Phloem–dissolvedsugar
Xylem–waterandminerals
photosynthesis
(gate)
(pore)
LeafFuncEon
Stomata–regulatepassageofCO2,O2andH2O
PreventdehydraEonandresulEngsunscald
Moststomataonlowerepidermis
TomatoLeaf–“colorized”electronmicrograph
LightInducedPotassiumPump
CO2entersforphotosynthesis
LeafVenaEon
LeafType
LeafArrangement
LeafModificaEon
Spinesaremodifiedleaves,sEpules,orpartsofleaves.
(Thornsaremodifiedbranchesorstems.)
(Pricklesaremorecomparabletohairs)
BullThistle
Spines
nosOpules=exsOpulate
Spinesaremodifiedleaves,sEpules,orpartsofleaves.
(Thornsaremodifiedbranchesorstems.)
(Pricklesaremorecomparabletohairs)
CitrusThorn
RosePrickles
LeafModificaEon
Atendrilisaspecializedstem,leaforpeEolewithathreadlike
shapethatisusedbyclimbingplantsforsupportand
aZachment,generallybytwiningaroundwhateverittouches.
LeafModificaEon
Bractsaremodifiedorspecializedleaves,especiallyones
associatedwithareproducEvestructuresuchasaflower.
SomebractsarebrightlycoloredandservethefuncEon
ofaZracEngpollinators.Examplesofthistypeofbract
includePoinselaandBougainvillea.
Euphorbiapulcherrima(poinsela)
Bougainvilleaglabra