Pharmaceutical Botany: Leaf Morphology, Structure, and Functions

Vocabulary practice flashcards covering leaf terminology, arrangement, margins, cross-sectional anatomy, stomatal mechanisms, transpiration, abscission, and leaf modifications from Pharmaceutical Botany lecture notes.

Blade

The broad, flat part of a leaf.

Petiole

The part of a leaf that attaches the blade to the stem.

Entire Leaf Margin

A smooth leaf margin with no indentations or incisions.

Crenate Leaf Margin

Leaf margins with shallow rounded or blunt teeth.

Serrate Leaf Margin

Leaf margins with pointed teeth directed forward, towards the apex of the leaf.

Crenulate Leaf Margin

Leaf margins with small rounded or blunt teeth; diminutive of crenate.

Dentate Leaf Margin

Leaf margins with pointed teeth directed outward, perpendicular to the midrib.

Double Serrate Leaf Margin

A coarsely serrate leaf margin with smaller teeth on the margins of larger teeth.

Denticulate Leaf Margin

Leaf margins with small pointed teeth directed outward, perpendicular to the midrib; diminutive of dentate.

Broad-Crenate Leaf Margin

Leaf margins with widely spaced, rounded or blunt teeth, found in many violets (Viola, Violaceae).

Serrulate Leaf Margin

Leaf margins with small pointed teeth directed forward, towards the apex of the leaf; diminutive of serrate.

Erose Leaf Margin

Leaf margins appearing gnawed with shallow, irregular indentations.

Revolute Leaf Margin

Leaf margins rolled inward on the lower surface of the leaf.

Involute Leaf Margin

Leaf margins rolled inward on the upper surface of the leaf.

Ciliate Leaf Margin

Leaf margins with hairs projecting outward from the edge.

Spinescent Leaf Margin

Leaf margins with stiff acuminate spines along the blade margin; also known as spinose.

Repand Leaf Margin

Leaf margins with very shallow indentations, cut less than $1/16$ the distance to the midrib.

Undulate Leaf Margin

Leaf margins with shallow indentations, wavy in a vertical plane.

Sinuate Leaf Margin

Leaf margins with shallow wavy indentations, cut $1/16$ the distance to the midrib.

Lobed Leaf Margin

Leaf margins with rounded lobes and rounded sinuses cut $1/4$ to $1/2$ the distance to the midrib.

Cleft Leaf Margin

Leaf margins with rounded lobes and convex or straight sinuses cut $1/4$ to $1/2$ the distance to the midrib.

Parted Leaf Margin

Leaf margins with lobes cut $1/2$ to $3/4$ the distance to the midrib.

Palmatifid

Palmately divided leaves with lobes cut $3/4$ to almost completely to the midrib.

Pinnatifid

Pinnately divided leaves with lobes cut $3/4$ to almost completely to the midrib.

Incised Leaf Margin

Jagged leaf margins cut sharply and deeply.

Lacerate Leaf Margin

Leaf margins irregularly cut, appearing torn.

Pectinate Leaf Margin

Leaf margins pinnately divided into fine, parallel segments, forming a comb- or feather-like appearance.

Dissected Leaf Margin

Leaf margins with narrow divisions finely subdivided into many smaller segments.

Photosynthesis

The biological process that includes the capture of light energy and its transformation into chemical energy of organic molecules (such as glucose), manufactured from carbon dioxide and water.

Cuticle

A waxy covering over the epidermis of aerial plant parts (leaves and stems) that enables survival in dry terrestrial environments.

Trichomes

Hair-like epidermal structures or outgrowths on the surface of plant leaves.

Stoma

Small pores in the epidermis of a stem or leaf flanked by guard cells, permitting gas exchange for photosynthesis and transpiration.

Guard Cell

One of two specialized epidermal cells that flank a pore to form a stoma.

Mesophyll

Photosynthetic ground tissue in the interior of a leaf containing air spaces for rapid diffusion of carbon dioxide, water, and oxygen.

Bundle Sheath

One or more layers of nonvascular cells (parenchyma or sclerenchyma) surrounding the vascular bundle in a leaf.

Privet (Ligustrum vulgare)

A eudicot whose leaf mesophyll contains distinct palisade and spongy sections.

Corn (Zea mays)

A monocot leaf with parallel veins that lacks distinct regions of palisade and spongy mesophyll.

Bulliform Cells

Large, thin-walled cells located on both sides of the midvein on the upper epidermis of certain monocots (grasses) that help leaves roll or fold inward during drought.

Proton Gradient

A difference in concentration of protons ($H^+$) across two sides of a cell membrane, holding potential energy used to synthesize ATP or perform cellular work.

Facilitated Diffusion

The diffusion of materials from a region of higher concentration to a region of lower concentration through specialized membrane passageways.

Transpiration

The loss of water vapor from the aerial parts of a plant.

Abscission

The normal, usually seasonal, falling off of leaves or other plant parts such as fruits or flowers.

Abscission Zone

The region composed primarily of thin-walled parenchyma cells where the leaf petiole detaches from the stem.

Bud Scale

A modified leaf that covers and protects the delicate meristematic tissue of winter buds.

Spine

A leaf modified for plant protection, such as a cactus spine.

Bract

A modified leaf associated with a flower or inflorescence that is not part of the flower itself.

Tendril

A modified leaf or stem used for holding onto or attaching to objects to support weak stems.

Bulb

A rounded, fleshy underground bud consisting of a short stem with fleshy leaves, specialized for food and water storage.

Flowerpot Plant (Dischidia rafflesiana)

An epiphytic plant with leaves modified into pots that collect water and organic matter brought by ants, which is then absorbed by special internal roots.

Pitcher Plant (Sarracenia purpurea)

A carnivorous plant with leaves modified into water-collecting pitchers where insect prey drown to provide nutrients.

Venus Flytrap (Dionaea muscipula)

A carnivorous plant whose leaves feature sensory surface hairs that detect insect touch and trigger folding to trap prey.