Plant Vegetative Organs

• Exercise 1 focuses on characterizing vegetative plant organs.

Objectives

• Identify plant vegetative structures and their functions.
• Learn the basics of phytography.
• Examine plants and note morphological characters.

Phytography

• Involves using descriptive terminology for plants and their parts.
• Provides a vocabulary for plant description, identification, and classification.
• Equips students for clear communication about plants using relative terms.
• Enhances critical observation and precise description of plants.

Leaf Structures

• Lamina: the leaf blade, or the widest part of the leaf
• Petiole: attaches the leaf to the stem
• Sessile: describes leaves attached directly to the plant stem, lacking a petiole
• Stipules: these are small, green appendages found at the petiole's base
• Midrib: extends along the leaf, branching to produce veins of vascular tissue on each side
• Margin: the edge of the leaf

Leaf Venation

• Venation describes the arrangement of veins in a leaf
• Parallel: this venation pattern is characteristic of monocots, features veins running straight without converging
• Reticulate: a net-like pattern found in dicot leaves
• Dichotomous: a pattern where veins fork, as seen in Ginkgo biloba

Parallel Venation Subtypes

• Penni-parallel (pinnate-parallel): secondary veins run parallel from a single primary vein
• Palmate-parallel: several primary veins emerge from one point; adjacent secondary veins connect via transverse veins

Reticulate Venation Subtypes

• Pinnately-netted: veins extend perpendicularly from the midrib
• Palmately-netted: four or more primary veins branch from a common base
• Ternately veined (ternate-netted): three primary veins arise from the same basal point

Types of Leaves based on Form

• Simple: blade composes of a single unit
• Compound: blade composed of multiple units

Compound Leaf Classifications

• Palmately compound: leaflets originate from a common point
• Pinnately compound: leaflets (pinnae) are borne on a rachis, continuing from the petiole
  • Odd-pinnate: uneven pinnate or imparipinnate
  • Even-pinnate: abruptly pinnate
  • Bipinnate: features two orders of pinnate axes, akin to a compound leaf
  • Tripinnate: means thrice pinnately compound
  • Unifoliolate: consisting of only one leaflet
  • Bifoliate: having two leaflets
  • Trifoliate or ternate: having three leaflets

Leaf Duration

• Annual: lives for one year or less
• Deciduous: leaves shed soon after maturity, typically in trees shedding simultaneously
• Diurnal: opens only during the day
• Ephemeral: lasts a day or less, applies to flowers
• Evergreen: persistent
• Fugacious or caducous: leaves fall off very early
• Nocturnal: opens during the night
• Persistent: remains and functions for over a year

Leaf Base Shapes

• Auricled or auriculate: Eared, with ear-like projections.
• Cordate: Heart-shaped with a sinus where the petiole attaches.
• Cuneate: Narrow to broad, wedge-like, tapering sides straight.
• Hastate: Base with basal lobes that flare outward.
• Oblique: Lower sides markedly unequal.
• Peltate: Shield-shaped, petiole attached at or near the center of the lower surface.
• Rounded: Sides are curved.
• Sagittate or arrow-shaped: "Ears" or lobes are acute and turned downwards

Leaf Shape Outline

• Acicular or acerose: Needle-shaped, slender, and round.
• Cordate: Heart-shaped.
• Cuneate: Wedge-shaped, tapering in straight lines to the base.
• Deltoid: Shaped like an equilateral triangle.
• Elliptic: Like an ellipse, equally rounded at both ends.
• Falcate: Curved shape.
• Filiform: Threadlike, very slender and cylindrical.
• Flabellate: Fan-shaped
• Lanceolate: Narrow and tapering towards the ends of a lance.
• Linear: Narrow, margins are parallel
• Lorate: Strap-shaped.
• Obdeltoid: Reverse of deltoid.
• Oblanceolate: Reverse of lanceolate
• Oblong: Sides nearly parallel through the middle.
• Ovate: Margins curved, widest near base.
• Obovate: Similar to ovate, but with the petiole at the narrow end.
• Oval: Somewhat like an elliptic
• Orbicular: Circular shape
• Peltate: Petiole attached to the lower surface
• Reniform: Shaped like a kidney
• Rhombic or rhomboidal: Shaped like a diamond

Leaf Apex Shapes

• Acuminate: Pointed, curved tapering lines.
• Acute: Tip ends in an acute angle with straight sides.
• Apiculate: Small sharp-pointed structure.
• Attenuate: Elongated tapering point.
• Caudate: Elongated and tail-like.
• Cirrhose: Filiform and coils.
• Cuspidate: Abrupt, firm and pointed structure.
• Emarginate: Prominently notched and indented.
• Mucronate: Apical short abrupt pointed structure.
• Obcordate: Reverse of cordate.
• Obtuse: Blunt or narrowly rounded.
• Retuse: Slightly notched.
• Rounded: Gently curved, broad and semi-circular in outline.
• Spinose: Develops into a spiny structure.
• Truncate: Seemingly cut-off, square or nearly so.

Leaf Margin Variations

• Ciliate: Fine hairs
• Circinate: Rolled inward from the top
• Crenate: Rounded teeth
• Crenulate: Diminutive of crenate
• Crispate: Curves in a vertical plane in minute waves.
• Dentate or toothed: Sharp teeth, point outward.
• Denticulate: Similar to dentate but with finer teeth
• Dissected: Cut into finer divisions.
• Doubly-serrate: Serrate margins that serrulate or bears teeth
• Entire: Smooth, margin has no indentation
• Involute: Rolled inward toward the upper side
• Lacerate: Margins are irregularly cut
• Laciniate: Leaf blade is cut into narrow ribbon-like segments
• Palmatifid: Palmately cleft or parted
• Pinnatifid: Pinnately cleft or parted
• Repand or Undulate: Slightly wavy or weakly sinuate
• Revolute: Rolled backward to the underside.
• Serrate: Cut into deep, sharp teeth pointing forward
• Serrulate: Diminutive of serrate
• Sinuate: Strongly wavy

Leaf Texture Types

• Cartilaginous: Hard, tough and often thin
• Chartaceous: Tough, leathery texture as in common bearberry
• Coriaceous: Leathery, rather thick and tough.
• Fleshy: Thick and soft.
• Hyaline: Thin and wholly transparent.
• Membranaceous: Thin, flexible, semi-transparent
• Scarious: Thin and dry, seemingly shriveled
• Suberous: Resembles that of a cork
• Succulent: Similar to fleshy but more juicy in appearance

Leaf Surface Characteristics

• Glabrous: Smooth; lacks hair or vestiture.
• Pubescent: Presence of hairiness:
  • Hirsute: Stiff and spreading hairs.
  • Hispid: Stiffer hairs, dense, erect, and straight.
  • Pilose: Long and soft hairs.
  • Puberulent: Very soft and short hairs.
  • Scabrous: Rough to the touch.
  • Floccose: Dense trichomes are present.
  • Strigose: hairs present are soft and stiff, closely appressed to the surface and pointing to one direction
  • Tomentose: hairs are woolly, the hairs are soft and more or less matted together
  • Arachnose or arachnoid: Cobwebby trichomes
  • Sericeous: Silky appearance

Leaf Arrangement

• Alternate: One leaf per node. Can be distichous (two-ranked) or spiral
• Opposite: Two leaves per node on opposite sides consisting of decussate (in pairs, alternating) or nondecussate
• Whorled or verticillate: Three or more leaves per node

Bud

• An immature shoot.
• Leaf scar is a layer of cork that seals the wound, keeping fungi and bacteria out and preventing water loss.

Lenticel

• A pore in the bark.

Root System Types

• Tap Root System: Dicot characteristic with a main root radiating lateral roots. - Secondary roots lead to succeeding root orders. - Woody Tap Root - Fleshy Tap Root
• Fibrous Root System: Common in monocots with equal-sized roots forming a dense mat without a distinct primary root
  • Grass type, Wiry type, Fleshy or fascicle type

Root System Based on Origin

• Primary or tap root: Derived from the radicle.
• Lateral or branched root: Originates in the pericycle.
• Adventitious roots: Arise from nodes and leaves.