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Life Cycle
Annual – completes life in one growing season Stages - germination, growth,
flowering, death Examples – marigolds, corn,
soybeans, impatiens, zinnias, wheat
Life Cycle
Biennial – completes life in two growing seasons Stages - germination, growth,
dormancy, growth (season 2), flowering, death
Examples – musk thistle, cabbage, primrose
Life Cycle
Perennial – will live for more than two growing seasons Stages - germination, growth,
flowering, dormancy, growth, flowering, etc.
May be woody or herbaceous Examples – Kentucky bluegrass, bur
oak, alfalfa, lilac, white clover
Growth Habit
Trees – woody perennials with a single, erect trunk
Shrubs – Woody perennials with more than one main trunk
Cacti – Perennials with spines and green fleshy stems
Growth Habit
Grasses – plants with jointed, round hollow stems, and parallel veins in leaves
Grass-likes – look similar to grasses without joints, triangular or round stems
Forbs – herbaceous broadleaf plants generally netlike veins in leaves
Foliage Retention
Deciduous – lose all leaves in autumn
Evergreen – retain leaves and remain green throughout the year Drop leaves throughout year, just not all at
once Broad-leaf or Needle-leaf
Leaf Characteristics Five common characteristics of leaves used
for identification Leaf arrangement on the stem Leaf venation pattern Complexity of the leaf Leaf shape Leaf surface
Arrangement on Stem Alternate – only 1 leaf per node
Opposite – 2 leaves per node
Whorled – 3 or more leaves per node
Venation Pattern Parallel – major veins run the length of the leaf,
parallel to the midrib, veins are about equal in size, found in grasses and grass-likes
Pinnate – have one major vein, with secondary veins branching from the midrib, found in trees, shrubs, and forbs
Palmate – have three or more major veins extending from the base of the blade and secondary veins branching from the main veins, found in trees, shrubs, and forbs
Leaf Complexity Simple – only 1 blade
Compound – several leaflets attached to a common leaf stalk Palmately divided – all leaflets branching
from 1 point Pinnately divided – leaflets arranged along
both sides of the leaf stalk (Even or Odd) Twice or Bi-pinnately divided – leaf stalk has 2
or more branches from main stalk
Leaf Shapes Cordate – heart-shaped
Deltoid – triangular shaped
Elliptical – broad in middle, tapers at both ends
Lanceolate – narrow with widest point at base
Linear – much longer than wide, sides parallel
Ovate – wide and broad at the base
Leaf Margins Crenate – broad, round teeth with narrow, open
spaces between them
Dentate – sharp teeth pointing outward
Entire – margin is smooth with no teeth or indentations
Lobed – indentations from ¼ to all of the way to the midrib
Serrate – saw-like teeth that are pointed forward
Leaf Surface Glabrous – surface is free of hairs
Glandular – surface has small glands which secrete resin
Hirsute – stiff hairs cover the surface
Pubescent – soft, short hairs cover the leaf surface
Scabrous – surface is rough to the touch, similar to sandpaper
Inflorescence Types The flower inflorescence is the arrangement of the
flowers on the stem. A few common types are: Corymb – short, broad, flat-topped Head – dense cluster of stalkless flowers Panicle – flowers developing toward the tips of the
branches as the elongate Raceme – flowers arranged along a main axis on
short stems Spadix – very small flowers massed together,
enclosed in a spathe Spike – flowers along a single axis Umbel – flat-topped cluster of flower, no central axis
Tree Fruits Drupe – fleshy with a single stone or pit (cherry)
Berry – fleshy with several seeds (persimmon)
Pome – fleshy outer coat and stony layer and several seeds within (apple, pear)
Legume – dry, elongated pod that splits in two with several seeds along one edge (honeylocust)
Capsule – dry fruit that splits to reveal many seeds inside (catalpa)
Tree Fruits Achene – small, dry, and hard one seeded fruit,
often tightly packed together with hundreds of fruits (sycamore)
Samara – one or two flat wings attached to a seed (maple)
Nut – hard, with an outer husk that does not split open readily and an inner papery to woody shell (black walnut)
Acorn – nut-like fruit of an oak, with a scaly or warty cap