Leaves

I WILL PASS.

Sheath

Substitutes the petiole in monocots; wraps around the stem and appears as an extension of the blade.

Blade/Lamina

The flat part of the leaf.

Sheath

Substitutes the petiole in monocots; wraps around the stem and appears as an extension of the blade.

Blade/Lamina

The flat part of the leaf.

Midrib

The middle primary vein.

Secondary/Lateral Veins

Veins that arise from the midrib.

Rachis

Extension of the petiole of a compound leaf that bears the leaflets.

Petiolule

A stalk of a leaflet in a compound leaf.

Leaflet

A leaf-like part of a compound leaf.

Petiole

A stalk that attaches a leaf to the main plant stem.

Dicot Leaf

Type of leaf has a well-defined petiole.

Monocot Leaf

Type of leaf that has a leaf sheath instead of a petiole.

Dicot Leaf

Type of leaf has a broad blade.

Monocot Leaf

Type of leaf has a long and narrow blade.

Dicot Leaf

Type of leaf is attached to the stem first, then to the node.

Monocot Leaf

Type of leaf has a sheath that directly attaches to the node.

Dicot Leaf

Type of leaf has an axillary bud at its base.

Ligule

A collar extension of the sheath in a monocot leaf that curves around the stem.

Ligule (Function)

In a monocot leaf, it protects from dirt and excess water entering between the leaf sheath and the stem.

Auricle

An appendage in a monocot leaf at the junction of the blade and sheath that surrounds the stem.

Auricle (Function)

In a monocot leaf, it strengthens and supports the blade.

Simple Leaf

A leaf with a single blade per petiole (e.g., Papaya, Gumamela).

Compound Leaf

A leaf divided into smaller leaflets but originates from a single axillary bud.

Pinnately Compound Leaf

Leaflets are attached along the rachis.

Unipinnate Leaf

Leaflets are attached to the primary rachis.

Bipinnate Leaf

Leaflets are attached to the secondary rachis.

Palmately Compound Leaf

All leaflets are attached at a common point at the end of the petiole (e.g., Umbrella plant).

Peltate Leaf (Simple Leaf)

The petiole is attached at the center of the leaf.

Perfoliate Leaf

The leaf is pierced by the stem; no petiole (sessile leaf).

Parallel Venation

Veins run parallel to one another; found in monocot leaves.

Pinnately Veined Leaf

A netted venation pattern with one primary vein (midvein) included within an enlarged midrib.

Palmately Veined Leaf

A netted venation pattern where several primary veins fan out from the base of the blade.

Uninervous Venation

Only has a midrib, with no branching veins.

Ternately Netted Venation

A netted venation pattern where three primary veins radiate from or just above the leaf base.

Dichotomous Venation

Veins fork into two at a common point, forming a "Y" shape that fans out.

Penni-parallel Venation

A central midvein with secondary veins that are parallel to one another.

Palmately Parallel Venation

Several conspicuous parallel veins extending from the base of the leaf.

Phyllotaxy

Arrangement of leaves on the stem.

Opposite Leaves

Two leaves per node, positioned opposite each other.

Whorled Leaves

Three or more leaves attached at the same node.

Alternate Leaves

One leaf attached per node only.

Rosette Leaves

Leaves lie close to each other at the base in a circular arrangement.

Linear

Leaf shape is a line.

Oblong

Leaf shape is an oblong.

Lanceolate

Leaf shape is a broader portion is towards the base (like a spear).

Oblanceolate

Leaf shape is the opposite of lanceolate.

Cuneate

Leaf shape is web-shape.

Spathulate

Leaf shape is a spatula.

Ovate

Leaf shape is an oval.

Obovate

Leaf shape is the opposite of ovate, typically broader at the base and tapered towards the tip.

Elliptical

Leaf shape is elliptical.

Rhomboid

Leaf shape is diamond/triangular.

Deltoid

Leaf shape is triangular but with an expanded base.

Orbicular (Peltate)

Leaf shape is round, with the petiole attached at the center.

Reniform

Leaf shape is kidney-shaped.

Cordate

Leaf shape is heart-shaped.

Cuneate

The base is angular or right-angled base.

Rounded

The base has a round shape.

Truncate

The base is straight or flat base.

Cordate

The base is heart-shaped.

Oblique

The base has unequal sides at the base.

Auriculate

The base is ear-like lobes.

Entire

Edges of the leaf are straight, smooth edges.

Undulate

Edges of the leaf are wavy.

Finely Serrate

The edges of the leaf are small, fine, pointed teeth.

Coarsely Serrate

The edges of the leaf are large, rough teeth.

Doubly Serrate

The edges of the leaf are smaller teeth on larger serrations.

Crenate

The edges of the leaf are rounded teeth along the edge.

Lobed

The edges of the leaf are deep indentations in the leaf margin.

Cuticle

Noncellular, outermost waxy covering of the leaf.

Upper Epidermis

Layer located beneath the cuticle.

Lower Epidermis

Located on the underside of the leaf; lacks a cuticle.

Mesophyll

Middle layer of the leaf, between the upper and lower epidermis (dorsiventral arrangement).

Palisade Mesophyll

Parenchyma cells arranged perpendicular to the epidermis, packed with chloroplasts, appearing darker.

Spongy Mesophyll

Loosely arranged cells with air spaces, making the leaf appear paler.

Xylem

Oriented towards the upper side of the leaf; conducts water and minerals.

Phloem

No vascular cambium, meaning the leaf remains in primary growth.

Stomata

Openings in the epidermis composed of two guard cells.

Stoma

The pore within the stomata that allows gas exchange.

Collenchyma

Living cells that provide flexible support to the leaf.

Bulliform cells

Large, thin-walled cells located at the upper epidermis; helps reduce water loss.

Monocot

These type of leaves are isobilateral.

Dicot

These type of leaves are dorsiventral.

Trichomes

Reduce too much water loss and protect the leaves from predatory animals.

Stomata

Pore or opening mostly in the lower epidermis.

Floating leaves

This leaf adaptation where stomata only on the upper epidermis.

Submerged leaves

Leaf adaptation where there are no stomates.

Xerophytes

This leaf adaptation has thick and reduced leaves. Stomata opens only at nighttime. Thick waxy layer.

Conifers

This leaf adaptation has waxy needle leaves. Evergreen. Thick, waxy cuticle. Sunken stomata.

Cotyledons ("Seed Leaves")

First leaves produced by a germinating seed; store food from the endosperm to help seedling growth.

Monocot Nutrition Source

Has one cotyledon and relies on the endosperm for nutrition.

Colored Bracts

Petal-like leaves that attract pollinators; brightly colored to compensate for small, inconspicuous flowers.

Insect-Trapping Leaves

Found in plants that digest insects to obtain nitrogen in nutrient-poor conditions.

Tendrils

Modified leaves or leaflets that cling to objects for support.

Spines

Found in cacti and euphorbs, leaves are reduced to spines to prevent water loss and deter herbivores.

Storage Leaves

Succulent leaves that retain water in large vacuoles.

Absorptive Leaves

One-cell-thick leaves that absorb water and minerals directly from the environment.

Reproductive Leaves

Leaves that produce plantlets along their margins.

Stipules

Leafy outgrowths at the base of the petiole; often photosynthetic.

Expanded Petiole

A widened petiole that functions in photosynthesis.

Window Leaves

Plants are partially buried, exposing a transparent window-like surface to capture light while reducing water loss.

Flower Pot Leaves

Leaves form structures that trap water and debris, providing nutrients to the plant.