Monocots, Dicots, Gymnosperms & Ferns

Plant Classification & Basic Plant Groups

for the Landscape

Classification of Plants

Taxonomic classification starts with the least specific – “it’s a plant”And ends with the most specific – “the individual plant by name”Kingdom

DivisionClass

OrderFamilyGenusSpecies

Classification of Plants

It all begins with the Plant Kingdom Kingdom PlantaeSimilarities They all photosynthesize

See Handouts:

Classifications of Living Organisms Traditionally Regarded as PlantsPlant Morphology: A Summary

Division

Division (synonymous with phylum)Suffix –phyta Divided into three (3) groups

Division

Seedless, nonvascular plantsBryophyta – the bryophytesMosses & liverworts

Division

Seedless vascular plantsSphenophyta – horsetailsPterophyta – fernsBoth used in landscaping

Division

Seed bearing vascular plantsCycadophyta – cycadsGinkgophyta – ginkgo or maidenhairConiferophyta – conifer Gnetophyta – gnetophytes All fall into the group “Gymnosperms” – naked seed

Division

Anthophyta – angiosperms Flowering plantsDivided into two (2) classesMonocotyledons – monocotsDicotyledons - dicots

Order

Groups of related families based on phylogenetic unity (fossil records, comparative anatomy, etc.)Suffix –alesRosales

Family

Grouped by similar generaSimilarities in floweringLarge families split into tribesSimilar tribes split into sub-familiesSimilarities in foliage are NOT reliable for identificationSuffix –aceaeRosaceae

GenusAlways italicized OR underlinedGeneric name formFirst part of Latin binomial naming systemComprises a group of obviously similar species

Genus

Usually related by reproductive organs and methodsCan be further broken down into sub-genera

species

In most cases it’s lowercase, italicized OR underlinedIn some cases it may be capitalized and in ‘Single Quotes’

species

Specific epithetSecond part of the Latin binomial naming systemRefers to an individual group

species

Groups typically do not cross sexuallySexual crosses are usually sterileSub-species are species separated by environmental factors

Varieties (var.)

Usually in ‘single quotes’Tends to be a variation in the speciesTypically naturally occurringMaybe only represented by something as simple as foliage color or growth habit

Cultivars (Cv.)

Often Capitalized and in ‘Single Quotes’Cultivated variety produced by horticultural techniques and breeding

Classification of Plants

Genus x speciesx = hybrid cross between two different speciesCan be naturally occurring or man-made

Classification of Plants

x Genus speciesx = hybrid cross between two different generaCan be naturally occurring or man-made

Horsetails

Division Sphenophyta Equisetum is the only genus in the divisionScouring rushAbout 35 species of Equisetum

Horsetails

Fossil recordsSeedless vascular plantsSpores not seedsJointed, tubular stemsStems grooved

Horsetails

RhizomatousInvasive in the landscape

Ferns

Division Pterophyta Primitive plant groupFossil records12,000 speciesSeedless vascular plantsSpores not seedSporophytesRhizomatous, clumping, single stem

Polystichum mandersonii

Ferns (cont.)

Adventitious rootsLeaves = frondsCompound pinnate frondsPinnae on rachis held up by petioleNew fronds = “fiddleheads”

Fiddleheads

Ferns (cont.)

HomosporusSori on underside of fronds Sporangia clustered in sori

Ferns (cont.)

Osmunda sp.

Pteridium sp.

Fern Life Cycle

Ferns (cont.)

Spores in the sporangium

Ferns (cont.)

Indusia covers the sori

Ferns (cont.)

Meiosis in sporangiumIndusium ruptures

SporangiumIndusium

Ferns (cont.)

Annulus cells contractLip cells ruptureSpores ejected

Ferns (cont.)

Spore germinates into filamentous gametophyteProtonema develops into prothallus

Filamentous Gametophyte

Ferns (cont.)

Rhizoids developAntheridium formsArchegonia formsFree water is necessaryFertilization occurs Zygote forms

Ferns (cont.)

Prothallus used as food sourceFirst leaf and rootsThe new sporophyte

Ferns (cont.)

Ferns (cont.)

GymnospermsDivisions Cycadophyta, Ginkgophyta, Coniferophyta & Gnetophyta“Naked Seeds”Primitive plantsFossil recordsNo flowersAbout 800 species

Gymnosperms (cont.)

Up to 15 cotyledonsNo endospermFood stored in female (1n) gametophyte tissue in seed

Gymnosperms (cont.)

Woody cones or leathery berries

Gymnosperms (cont.)

Gymnosperms (cont.)“Leaves” have one or two vascular bundlesNo cambium in foliage

Gymnosperms (cont.)

Woody and branchingRoot system also woody and branchingWind pollinatedVascular tissue in stems in discrete rings

See Handouts:

Principles of Horticulture: Plant Structures and Pruning by G.B. Smith

Gymnosperms (cont.)

NeedlesNeedle-likeOverlapping scalesFused overlapping scalesPines in fascicles

Cycadophyta

Cycas sp.

Ginkgophyta

Coniferophyta

Gnetophyta

Welwitschia

Welwitschia

Ephedra

Gnetum

The Flowering Plants

Division AnthophytaAngiospermsFlowering plantsAngiosperms divided into two

groups1. Monocotyledones – the monocots2. Dicotyledones – the dicots

Monocots vs. Dicots

About 235,000 species of flowering plantsAbout 170,000 species of dicotsAbout 65,000 species of monocots

Flower Parts

Monocot flower parts in 3s

Flower Parts

Dicot parts in 4s and 5s

Flower Parts

See Handouts:

The Flower SummaryOverall Flower Morphology

Flower Morphology

Morphology refers to shapea : branch of biology that deals with the form and structure of animals and plants

b : the form and structure of an organism or any of its parts

Merriam Webster online dictionary

Flower Morphology

Stigma, style and ovaryCollectively referred to as the pistilFemale parts of the flower

Flower Morphology

Anther and filamentCollectively referred to as the stamenPollen occurs on the antherMale parts of the flower

Flower MorphologyPetals – modified leavesOften large and scented in insect pollenated plants Small and dull in wind pollinated plantsCorolla – the collective term for flower petals

Flower Morphology

Not all flowers have separate petalsHence the term corolla

Flower Morphology

Sepals – modified leavesSome green, some coloredCalyx – the collective term for sepals

Flower Morphology

Monoecious both sexes occurring on the same plant . . . in separate male and female flowers

Flower Morphology

Dioecioussexes occurring in separate plantsin separate male and female flowers

Flower Morphology

Hermaphrodite (bisexual)

both sexes occur in same flower

Flower Morphology

Complete flowerscontains all four main flower partscorolla, calyx, pistil & stamen

Incomplete flowersmissing any one or more of the four parts

Flower Morphology

Perfect flowerscontains both pistil and stamen in the same flower

Imperfect flowersmissing either pistil or stamen

Symmetry

Bilateral symmetryRight mirrors leftTop does not mirror bottom

Pelargonium peltatum

Ivy Geranium

Symmetry

Radial symmetryRight mirrors leftTop mirrors bottom

Malus sp.

Crabapple

Seeds

Monocot Seeds have endosperm for food storage

Seeds

Dicots use cotyledons for food stores

Cotyledons

Monocots have a single cotyledon

Cotyledons

Dicots have a pair of cotyledons

Cotyledons

The Vascular System

Monocots have random vascular bundles

The Vascular System

Dicots have discrete vascular rings

Above the Ground

Monocots are non-woodyThey tend to be leafy

Above the Ground

Dicots are woody and branching

The Leaves

Monocots have parallel venation

The Leaves

More parallel venation

The Leaves

Monocot leaves tatter in the wind

The Leaves

Dicots have netted venation

The Root System

Monocots have a fibrous root system

The Root System

Dicots have a woody, branching root system