Leaf Morphology & Indentification 2015-09-20

In botany, leaf shape is a description of the form of the part of a plant known as the leaf. It is characterised with the following terms (with botanical Latin in italics in brackets) to describe the shape of leaves:

• Acicular (acicularis): Slender and pointed, needle-like
• Acuminate (acuminata): Tapering to a long point
• Acute: Pointed, having a short sharp apex angled less than 90°
• Aristate (aristata): Ending in a stiff, bristle-like point
• Asymmetrical: With the blade shape different on each side of the midrib
• Basal: Arising from the root crown, bulb, rhizome or corm, etc., as opposed to cauline
• Bipinnate (bipinnata): Each leaflet also pinnate
• Caudate: Tailed at the apex
• Cauline: Borne on the stem, as opposed to basal
• Compound: Not simple; the leaf is broken up into separate leaflets, and the leaf blade is not continuous
• Cordate (cordata): Heart-shaped, with the petiole or stem attached to the cleft
• Cuneate (cuneata): Triangular, stem attaches to point
• Deltoid (deltoidea) or deltate: Triangular, stem attaches to side
• Digitate (digitata): Divided into finger-like lobes
• Elliptic (elliptica): Oval, with a short or no point
• Entire: Having a smooth margin without notches or indentations
• Falcate (falcata): Sickle-shaped
• Fenestrate (fenestrata): "Windowed" with holes (e.g. Monstera deliciosa or Aponogeton fenestralis), or window-like patches of translucent tissue. (cf. Perforate)
• Filiform (filiformis): Thread- or filament-shaped
• Flabellate (flabellata): Semi-circular, or fan-like
• Hastate (hastata), spear-shaped: Pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base
• Laciniate: Very deeply lobed, the lobes being very drawn out, often making the leaf look somewhat like a branch or a pitchfork
• Laminar: Flat (like most leaves)
• Lance-shaped, lanceolate (lanceolata): Long, wider in the middle
• Linear (linearis): Long and very narrow
• Lobed (lobata): With several points
• Mucronate: Ending abruptly in a sharp point
• Obcordate (obcordata): Heart-shaped, stem attaches to tapering point
• Oblanceolate (oblanceolata): Top wider than bottom
• Oblong (oblongus): Having an elongated form with slightly parallel sides
• Obovate (obovata): Teardrop-shaped, stem attaches to tapering point
• Obtuse (obtusus): With a blunt tip
• Orbicular (orbicularis): Circular
• Ovate (ovata): Oval, egg-shaped, with a tapering point
• Palmate (palmata): Consisting of leaflets or lobes radiating from the base of the leaf.
• Pandurate: fiddle-shaped
• Pedate (pedata): Palmate, with cleft lobes
  • Pedatifid (pedatifida): Nearly pedately divided, but not as deeply
• Peltate (peltata): Shield-shaped with stem attached underneath (cf. pelta)
• Perfoliate (perfoliata): Stem through the leaves
• Perforate (perforata): marked with patches of translucent tissue, as in Crassula perforata and Hypericum perforatum, or perforated with holes (cf. "Fenestrate")
• Pinnate (pinnata): Two rows of leaflets
  • Odd-pinnate, imparipinnate: Pinnate with a terminal leaflet
  • Paripinnate, even-pinnate: Pinnate lacking a terminal leaflet
  • Pinnatifid and pinnatipartite: Leaves with pinnate lobes that are not discrete, remaining sufficiently connected to each other that they are not separate leaflets.
  • Bipinnate, twice-pinnate: The leaflets are themselves pinnately-compound
  • Tripinnate, thrice-pinnate: The leaflets are themselves bipinnate
  • Tetrapinnate: The leaflets are themselves tripinnate.
• Pinnatisect (pinnatifida): Cut, but not to the midrib (it would be pinnate then)
• Serenoa seedlings have pleated elliptic leaves, but mature plants have pleated palmate leaves.
• Plicate (plicatus, plicata): folded into pleats, usually lengthwise, serving the function of stiffening a large leaf.
• Pungent (spinose): Having hard, sharp points.
• Reniform (reniformis): Kidney-shaped
• Retuse: With a shallow notch in a broad apex
• Rhomboid (rhomboidalis): Diamond-shaped
• Round (rotundifolia): Circular
• Sagittate (sagittata): Arrowhead-shaped
• Simple: Leaf blade in one continuous section, not divided into leaflets (not compound)
• Spear-shaped: see Hastate.
• Spatulate, spathulate (spathulata): Spoon-shaped
• Subulate (subulata): Awl-shaped with a tapering point
• Subobtuse (subobtusa): Somewhat blunted, neither blunt nor sharp
• Sword-shaped (ensiformis): Long, thin, pointed
• Terete: Circular in cross-section; more or less cylindrical without grooves or ridges.
  • Semiterete: Rounded on one side, but flat on the other.
• Trifoliate (trifoliata), trifoliolate (trifoliolata), or ternate (ternata): Divided into three leaflets
• Tripinnate (tripinnata): Pinnately compound in which each leaflet is itself bipinnate
• Truncate (truncata): With a squared-off end
• Undulate (undulatus): Wave-like
• Unifoliate (unifoliata): With a single leaf