Leaf Anatomy

Front 1

Complete Leaf

Back 1

Blade = lamina, the flat part of petiole (the leaf stalk)
Stipules - the little blade like appendages where the leaf meets the stem

Front 2

Epidermis

Back 2

usually covered with a secreted non cellular layer of cuticle

Front 3

Adaxial epidermis

Back 3

that portion toward the leaf axil the 'upper' surface

Front 4

Abaxial epidermis

Back 4

that portion away from the axil, the 'lower' surface

Front 5

Guard cells

Back 5

both monocots and dicots have more of these cells in the abaxial epidermis where the escaping H2O vapor will be held a little longer near the leaf. Monocots guard cells are more evenly, borne on the adaxial and abaxial surfaces (upright)

Front 6

Bulliform cells

Back 6

found in many monocot leaves; these cells have a very thin wall and large vacuoles and may help leaves unroll or store water

Front 7

Mesophyll

Back 7

the parenchmous tissue (chlorenchyma) which is between the layers of the epidermis (photosythesis location) Dicots mesophyll is divided into two layers

Front 8

Palisade layer

Back 8

toward the adaxial surface (dicot) is tightly packed with chlorenchyma

Front 9

Spongy layer

Back 9

toward the abaxial surface is loosely organized with lots of air space for easy entry of CO2. This is where stomates are on the abaxial surface

Front 10

Veins

Back 10

the vascular tissue, embedded in the mesophyll. It is continuous from the stem into the petiole; if present, and from there into the blade

Front 11

Xylem and Phloem location in leaves

Back 11

X is toward adaxial, Ph is closer to the abaxial. The vascular tissue is surrounded by fibers

Front 12

Dicot veins (pattern)

Back 12

found in netted or branched. Some have main vein called midrib or midvein

Front 13

Monocot veins (pattern)

Back 13

found in parallel arrangement to one another....no main vein

Front 14

Gynosperm (venation and leaf shape)

Back 14

Centric venation, with rounded leaves, epidermis is usually heavily cutinized and has sunken stomata. Mesophyll consists of compact parenchyma cells, whose walls form projections that extends from the lumens. Resin channels are also found in this tissue.

Front 15

Transfusion tissue

Endodermis

Back 15

surrounds the central vein

inner boundary of the mesophyll lies next to a well differentiated area known as...

Front 16

phyllotaxy

possible patterns (Angiosperms)

possible patterns (Gymnosperms)

Back 16

in a Leaf - a lateral outgrowth of a stem, determines size, arising exogenously at a node in a definite pattern of succession called

Alternate - one leaf per node
Opposite - 2 leaves per node
Whorled - 3 or more leaves per node

typically spiral around a stem

Front 17

Functions of a leaf

Back 17

Photosynthesis
Protect other plant parts
Store starch and waters
Digests insect
help suppport the stem
attact or hold pollinators
Asexual propapagation

Front 18

Sessile

Back 18

Leaves lacking a petiole

Front 19

Fascicle

Back 19

pine leaves are borne in a cluster, held together by a sheath

Front 20

Apetiolate

Back 20

the lower portion of each leaf, called the sheath, wraps around the main axis of the shoot

Front 21

Ligule

Back 21

Where the blade and sheath join, there is a hairy membranous structure in the axil

Front 22

Collar

Back 22

Across from the ligule, but outside the blade; usually white or light green.

Front 23

Auricles

Back 23

Some species of grass produce two clawlike extensions of the blade's base

Front 24

Venation

Back 24

is the arrangement of veins in the blade

Front 25

Vein types

Back 25

Netted - large veins from which smaller ones diverge

Parellel - veins of about equal size are parallel to one another, running longitudinal

Front 26

Pinnate

Palmate

Centric

Back 26

one major vein, called midrib, from which secondary veins diverge on either side

two or more major veins diverge from base of the blade, with 2ndary arising from them

one or two unbranched vascular bundles are located in the center of the leaf (typical Gynosperm)

Front 27

Simple

Compound

Back 27

undivided

divided into smaller units called leaflets

Front 28

Pinnately Compound

Palmately Compound

Back 28

leaflets arise from along either side of an extension of the petiole called rachis

leaflets arise from the top of the petiole, giving leaf a rounded look

Front 29

Glabourous (surface)
Pubescent
Tomentose
Scabrous
Glaucous
Rugose
Glandular
Coriaceous vs membranous

Back 29

Smooth and Glossy (weeping fig)
Fine soft short hairs (some azaleas)
Covered with curled, matted woolly hairs (leatherleaf viburnum)
Feel rough (apple)
White to bluish waxy bloom which can be rubbed off (blue spruce)
wrinkled, with sunken veins (zebra)
bear oil or resin glands (pine)
Thick and leathery (leatherleaf) vs membranous (bloodleaf)

Front 30

Leaf Shapes

Back 30

Broad; most deciduous, some evergreens

Narrow; Conifers, some evergreens (needle, scale, or awl like)