Scientific Identification & Classification

Plant Parts

• Leaves

• Stems

• Roots

• Flowers

Leaves-External

• Petiole-leaf stalk or part that connects the leaf to the stem

• Blade-the large, flat part of the leaf

• Midrib-the large center vein

• Veins-the structural framework of the leaf

• Margin-the edge of the leaf

Leaves-External

Vein Pattern

Leaf Arrangement

Alternate Opposite Whorled

Leaf Type

Simple

Compound

Leaf Type

Needle

Awl Scale

Leaf Shapes

Cordate Elliptical Ovate Spatulate Deltoid

Lanceolate Linear

Star

Leaf Margin

Internal Parts • Upper and lower epidermis - is the skin

of the leaf that prevents the loss of too much moisture.

• Stomates - are the small openings under the leaf for breathing or transpiration.

• Guard cells - surround the stomates and regulate the open and close of the stomates.

• Chloroplasts - are small green particles that contain chlorophyll, give leaves their green color and are necessary for photosynthesis.

Functions of the Leaf

• Photosynthesis is a process by which plants capture sunlight and use it to convert carbon dioxide and water into food.

• Respiration converts sugars and starches into energy.

• Transpiration is the release of water vapor from the leaves of plants. It also cools the plant.

Misc. Leaf Terms • Sessile - describes leaves without a

petiole (example zinnia).

• Bracts - are modified leaves (example poinsettia).

• Needles and scales - modified leaves (example pine tree).

• Glabrous leaves or stems - have a smooth non-hairy feel (example southern magnolia).

• Pubescent leaves or stems - have a hairy feel (example African violet).

Stems • Movement of Materials

• Support of the leaves and reproductive structures

• Food storages

• Reproduction with stem cuttings or grafting

Stems-External • Lenticels –

breathing pores found on stems and branches

• Bud scale scars – where terminal buds have been located

• Leaf Scars – Where leaves were attached

External Parts, continued…

• Terminal bud – found on the end of a stem

• Axillary or lateral bud – located at the axil of the leaf

• Lateral buds – on side of stem

Internal Parts • Xylem is the tissue

that transports water and nutrients up from the roots to the stems and leaves.

• Phloem is the tissue that transports food down from leaves to the roots.

Internal Parts, continued

• Cambium is a thin, green, actively growing tissue located between the bark and wood and produces all new stem cells.

• Bark is old inactive phloem.

• Heartwood is old inactive xylem.

• Sapwood is new active xylem.

Cotyledons • Monocots are plant stems that have

vascular bundles each bundle contain both xylem and phloem. They produce one seed leaf. Examples are grasses and corn.

• Dicots are plant stems that have a phloem layer and a xylem layer separated by cambium. They produce two seed leaves. Examples are trees and many vegetable plants.

Stems-Internal

• Dicot: example: trees

• Monocot : examples: corn, grasses

Functions of Stems

• Translocation – move water and minerals from roots up to leaves & move food/nutrients from leaves down to the roots

• Xylem and phloem cells help with this process.

Stems-Internal (Translocation)

• Xylem-tissue that transports water and nutrients up from the roots to stems and leaves

• Phloem-tissue that transports food down from leaves to roots

Phloem Phloem

Xylem

Functions of Stems, Leaves & Roots

• Transpiration – loss of water through the leaves or stems of plants

• Transpiration exchange gases as oxygen and carbon dioxide

–Occurs in stomas and lenticels

Thorns & Prickles

Thorn

Prickle

Modified Stems

Stolon

Tuber

Cladophyll

Root Functions

• Anchor the plant and hold it upright

• Absorb water and minerals from the soil and conduct them to the stem

• Store large quantities of plant food

• Asexual Reproduction or reproduce some plants

External Parts

• Root cap-indicates growth of new cells

• Root hairs-absorb moisture (water) and minerals

Internal Parts • Much like stems in that they

have a phloem, cambium, and xylem layer

• Phloem-the outer layer that carries food down the root

• Xylem-the inner layer that carries water and minerals up to the stem

Root Types

Fibrous Roots:

Many branched shallow roots, are easier to transplant

Tap Root:

Long root with few branched

ones

Functions of Flowers

• Produce seeds used for sexual reproduction

• Attract insects for pollination (Pollination is the transfer of pollen from anther to stigma.)

• Produce fruit to protect, nourish and carry seeds

External Flower Parts

• Sepals-Green parts that cover and protect flower bud before it opens

• Petals-are really leaves that are modified to attract insects for flower pollination, the pretty part that we call flowers

Internal Flower Parts • Stamens are the male flower

parts.

–The anther is a sac-like structure that contains pollen and the male sex cells.

–The filament is a short stalk that holds up the anther.

Internal Flower Parts • Pistil is female parts of the flower.

–The stigma is the sticky part on top of the style where insects leave pollen.

–The style holds up the stigma and connects it to the ovary.

–The ovary if fertilized becomes a fruit.

–The ovules are the eggs or female sex cells that become seeds if fertilized.

Stamen

Anther

Filament

Calyx

Sepal

Ovary

Style

Female

Pistle

Petal

Corolla

Flowers

Parts of the Stamen

• Filament-short stalk that holds up the anther

• Anther-a sac-like structure that contains pollen, the male sex cells

Parts of the Pistil

• Stigma-sticky part on top of style where insects leave pollen

• Style-holds up the stigma and connects it to the ovary

• Ovary-if fertilized becomes a fruit or seed coat

• Ovules-the eggs or female sex cells that become seeds if fertilized

Complete-vs-Incomplete

• Complete flowers have both male and female parts

• Incomplete flowers have only male or female parts

Monoeciuos

• All male or all female flowers on plant

• Examples: Hollies or Ginkgo

Male Female

Dioecious • Male and female, imperfect flowers

on same plant

• Examples: Squash & Pumpkin

Flower Types

Corymbs

Panicle

Umbel

Flower Types

Head Spike

Additional Info •Fertilization - is when pollen travels down the style, joining the sperm and the ovule. •Pollination - is the transfer of pollen from the anther to the stigma. •Cross-pollination - is the transfer of pollen from the stamen to the stigma of one flower to a flower on another plant. •Self-pollination - is the transfer of the pollen to the stigma of a flower on the same plant.

Additional Information • Corolla - is all auxiliary parts of the

flower not including reproductive organs. The collective term for all petals of a flower.

• Calyx - is the external usually green or leafy part of a flower. It is also the collective term for all sepals of a flower.

• Receptacle - is the enlarged tip of a stem on which a flower is born.

Fruit

• The fruit serves as protection for the seeds.

• The function of the fruit is to help with seed dispersal.

• The juvenile stage is when a plant first begins growing from a seed.

Plant Parts-Fruit

• Cones

• Nut (acorn)

• Clusters or drupes (raspberry)

• Capsules (willow)

• Samara (maple)

Types of Fruits • Pome - is a fleshy fruit which has a

central core that usually has five seeds and is surrounded by a thick outer layer. Examples are apples and pears.

• Drupe - is a fleshy fruit which has one seed enclosed in a hard stony material. Examples are plum, peach and cherry.

• Berry - is an entire ovary that is fleshy and often juicy with thin skin. Examples of a berry are tomato and grape.

• Modified berry - is like a berry but with a tough covering. Examples are grapefruit and cucumber.

• Aggregate fruit - are compound fruit composed of many tiny drupes clustered on a single receptacle. Examples are blackberry and raspberry.

• Accessory fruit are small and hard and are scattered over the surface of the receptacle. The edible part forms an enlarged receptacle with seeds usually on the outside. An example is a strawberry.

•

• Multiple fruit is a compound fruit formed from several flowers in a cluster. Examples are pineapple and mulberry.

Fruits and Nuts

Cones Acorns

Cluster Drupe

Fruits and Nuts

Samara

Capsule

Pome

Aggregate

Video Links

(1) Travelling

(2) Growing

(3) Flowering

(4) Social Struggle

(5) Living Together

(6) Surviving