Morphological Characteristics of Flowers

Resource for understanding the morphological characteristics of flowers. This guide provides detailed descriptions of flower shapes, inflorescence patterns, and leaf features such as arrangement, petiole length, shape, margin, and venation.

Last changed on 2024-12-18

Flower Shapes

Flower shapes are an important characteristic used in plant identification.

Campanulate (Bell-shaped): Flowers that resemble a bell, with petals that flare out at the base.
Cupulate (Cup-shaped): Flowers that form a broad, open cup-like shape, wider at the opening.
Discoid (Disk-shaped): Flat, circular flowers, often seen in the Asteraceae family.
Funnelform (Funnel-shaped): Flowers that are shaped like a funnel, wider at the opening and narrowing towards the base.
Papilionaceous (Pea-like): Characteristic of the Fabaceae family, with a banner, wings, and keel.
Rotate (Wheel-shaped): Flat, open flowers with petals that spread out horizontally.
Solitary: A single flower that grows individually on its own stem, not part of a cluster or group.
Stellate (Star-shaped): Flowers with petals that spread out like a star.
Tubular: Long, tube-like flowers, often with a narrow opening.
Urceolate (Urn-shaped): Flowers that are shaped like an urn or vase, with a narrow opening at the top.
Zygomorphic: Flowers with bilateral symmetry, having distinct upper and lower parts, divisible into equal halves in only one plane.

Inflorescence

Inflorescence refers to the arrangement and pattern of a cluster of flowers on a plant. It describes how the flowers are grouped together on the stem and can vary significantly among different plant species.

Capitulum: A dense cluster of sessile or nearly sessile flowers, as seen in daisies and sunflowers.
Catkin (Ament): A slim, cylindrical inflorescence with inconspicuous flowers, often wind-pollinated.
Corymb: A flat-topped or slightly rounded inflorescence with the outer flowers opening first.
Cyme: A flat or convex inflorescence where the central flowers open first.
Panicle: A branched inflorescence with multiple racemes or spikes.
Raceme: A simple inflorescence with flowers on short stalks (pedicels) along a central stem.
Spike: Similar to a raceme, but the flowers are directly attached to the central stem without pedicels.
Umbel: A cluster of flowers with stalks of nearly equal length that spread from a common point, resembling an umbrella.

Leaves Arrangement

Leaf arrangement, or phyllotaxy, is an important characteristic used in plant identification.

Alternate: Leaves are arranged singly at different heights along the stem, with one leaf per node.
Basal: Leaves grow from the base of the stem, often forming a rosette.
Opposite: Two leaves arise at the same level from opposite sides of the stem, with pairs of leaves at each node.
Rosette: Leaves are arranged in a circular pattern at the base of the plant, often close to the ground.
Spiral: Leaves are arranged in a spiral pattern around the stem, which is a variation of the alternate arrangement.
Whorled: Three or more leaves grow from a single node, encircling the stem.

Leaves Petiole

Leaf petiole refers to the stalk that connects a leaf blade to the plant stem, providing support and transport of nutrients and water.

Long: Petioles that are noticeably elongated, allowing the leaf blade to be positioned further from the stem.
Sessile: Leaves that lack a petiole entirely and are directly attached to the stem.
Short: Petioles that are relatively short compared to the leaf blade, often making the leaves appear closer to the stem.

Leaves Shape

Leaf shape is a key characteristic in plant identification.

Cordate: Heart-shaped, with a notch at the base.
Elliptic: Oval-shaped, with the widest part in the middle and tapering equally towards both ends.
Lanceolate: Shaped like a lance head, longer than wide, and tapering to a point at the apex.
Linear: Long and narrow, with parallel sides.
Lobed: Having distinct protrusions or lobes, which can vary in depth and number.
Obovate: The inverse of ovate, with the broader end at the apex.
Orbicular: Circular or nearly circular.
Ovate: Egg-shaped, with the broader end at the base.
Pinnate: Feather-like, with leaflets arranged on either side of a central axis.
Reniform: Kidney-shaped, with a rounded base and a notch.
Sagittate: Arrowhead-shaped, with lobes pointing downward.
Spatulate: Spoon-shaped, with a broad, rounded end and tapering to a narrow base.

Leaves Margin

Leaf margin refers to the edge of a leaf and is an important feature for plant identification.

Crenate: Rounded teeth or scalloped edges.
Dentate: Toothed, with teeth pointing outward rather than forward.
Double Serrate: Serrate with smaller teeth on the larger teeth.
Entire: Smooth, with no teeth or lobes.
Incised: Deeply cut, with sharp, irregular notches.
Lobed: Indented with rounded or pointed projections (lobes).
Serrate: Saw-toothed, with sharp teeth pointing towards the leaf tip.
Serrulate: Finely serrate, with very small teeth.
Sinuate: Deeply wavy, with more pronounced curves than undulate.
Undulate: Wavy, with a gentle up-and-down pattern along the edge.

Leaves Venation

Leaf venation refers to the pattern of veins in a leaf, which can be a useful characteristic for plant identification.

Arcuate: Veins curve towards the leaf margin, often seen in leaves with a smooth edge.
Dichotomous: Veins fork repeatedly into two equal branches, seen in some ferns and ginkgo leaves.
Palmate: Several main veins radiate out from a single point at the base of the leaf, similar to the fingers of a hand.
Parallel: Veins run parallel to each other along the length of the leaf, common in many monocots like grasses.
Pinnate: A central main vein (midrib) with smaller veins branching off to the sides, resembling a feather.
Reticulate (Net-like): A network of interconnected veins, forming a web-like pattern, typical in many dicots.