Plant Anatomy – Leaves, Stems & Roots

Vocabulary flashcards covering major terms and definitions related to leaves, stems, and roots in plant anatomy, emphasizing monocot–eudicot differences, tissue types, and physiological processes.

Plant Anatomy

The study of the internal structure of plants, including leaves, stems, and roots.

Leaf

Primary organ that captures sunlight and produces sugars through photosynthesis.

Photosynthesis

Process by which plants convert CO₂ and H₂O into glucose and O₂ using light energy (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂).

Leaf Venation

Pattern of veins in a leaf; can be parallel or netted.

Parallel Venation

Veins run side-by-side from base to tip; characteristic of monocots.

Netted Venation

Veins form an interconnecting network; common in eudicots.

Palmately Net-Veined

Major veins spread from one point like fingers on a hand; eudicots only.

Pinnately Net-Veined

One main midrib with smaller veins branching sideward; eudicots only.

Phyllotaxy

Arrangement of leaves on a stem.

Alternate Leaf Arrangement

One leaf per node, switching sides along the stem.

Opposite Leaf Arrangement

Two leaves per node positioned directly across from each other.

Whorled Leaf Arrangement

Three or more leaves arise from a single node.

Simple Leaf

Leaf with a single undivided blade.

Palmately Compound Leaf

All leaflets originate from a common point at the end of the petiole.

Pinnately Compound Leaf

Leaflets attach along the length of the petiole.

Bipinnately Compound Leaf

Leaflets are further divided into smaller leaflets on secondary axes.

Axillary (Lateral) Bud

Bud located at the junction of stem and leaf; present only at true leaves, not leaflets.

Epidermis (Leaf)

Outermost cell layer of a leaf, lacking chloroplasts and thus non-photosynthetic.

Cuticle

Waxy covering on the epidermis that reduces water loss.

Trichome

Hair-like epidermal outgrowth that defends against herbivores and decreases water loss.

Stoma (plural Stomata)

Pore in the epidermis that allows gas exchange.

Guard Cells

Pair of kidney-shaped cells that open or close a stoma by changing turgor.

Transpiration

Evaporation of water from leaf surfaces, generating upward pull of water through xylem.

Mesophyll

Photosynthetic ground tissue inside the leaf.

Palisade Mesophyll

Columnar, chloroplast-rich mesophyll cells; found in eudicots for light absorption.

Spongy Mesophyll

Loosely arranged mesophyll with air spaces for gas diffusion; found in both groups.

Vascular Bundle (Leaf Vein)

Strand of xylem and phloem located in mesophyll tissue; responsible for water and nutrient transport.

Xylem

Vascular tissue that transports water and minerals upward from roots.

Phloem

Vascular tissue that transports sugars and other organic products throughout the plant.

Sap

Fluid in vascular tissues; xylem sap carries water/minerals, phloem sap carries sugars.

Herbaceous Stem

Non-woody stem; soft and green, with discrete vascular bundles.

Woody Stem

Stem that undergoes secondary growth, producing wood (secondary xylem).

Growth Rings

Annual concentric layers of xylem indicating seasonal growth in woody stems.

Cambium (Vascular Cambium)

Lateral meristem producing secondary xylem inward and secondary phloem outward.

Bark

All tissues external to the vascular cambium, including phloem, cork cambium, and cork.

Pith

Central parenchyma region of a stem that stores starch.

Sclerenchyma

Support tissue consisting of thick-walled, lignified cells (fibers or sclereids).

Root

Plant organ that anchors the plant, absorbs water/minerals, and stores carbohydrates.

Endodermis

Innermost cortex layer in roots; regulates flow into the vascular cylinder (stele).

Stele

Central vascular cylinder of a root containing xylem, phloem, and sometimes pith.

Mesophytic Plant

Plant adapted to moderate, well-balanced environments; typical leaf anatomy.

Xerophytic Plant

Plant adapted to dry habitats; features include closely packed cells, sunken stomata, and long trichomes.

Hydrophytic Plant

Plant adapted to aquatic habitats; has reduced stomata and vascular tissue.

Crypt

Pit in xerophytic leaves containing stomata and trichomes to minimize water loss.