Dendrology Flashcards

Core Definitions and Concepts in Dendrology

  • Dendrology = study of woody plants (trees, shrubs, vines) focusing on identification, classification, nomenclature, morphology, geographic range, phenology, ecology

  • Dendrology = Woody plant taxonomy + Silvics

  • Taxonomy components: identification, classification, nomenclature, morphology, geographic range, phenology, ecology

  • Silvics components: how species respond to environmental conditions (drought, shade, wind, herbivores, flooding, nutrients, fire, soil)

  • Pivotal terms:

    • Taxonomy

    • Silvics

    • Morphology

    • Phenology

    • Ecology

Tree Identification: Practical Framework

  • Tree ID considerations:

    • Where are you? Range and habitat

    • Leaves: arrangement, shape, margins, pubescence, aroma, taste

    • Stems and buds

    • Flowers and/or fruit (and look on the ground for dropped parts)

    • Bark

    • Form

    • Combine multiple characteristics; avoid relying on a single feature

Leaf Terminology (Key Parts)

  • Margin

  • Midrib

  • Leaf terminology: petiole, base, lateral vein, apex, blade

  • Subtle underside features: axillary hairs, sinuses, etc.

  • Petiole (leaf stalk)

  • Blade (leaf blade)

Leaf Surface and Margins: Common Features

  • Bristle tips

  • Lobe pattern

  • Axillary hairs (underside)

  • Sinus (indentations between lobes)

  • Margin (edge) and leaf base

  • Petiole and midrib (central vein)

Leaf Arrangements

  • Alternate: one leaf per node

    • Example: American beech, Fagus grandifolia (NJL listed)

  • Opposite: two leaves per node

    • Example: Red maple, Acer rubrum (NJL listed)

  • Whorled: three or more leaves per node

    • Example: Southern catalpa, Catalpa bignonioides (NJL listed)

Leaf Types and Leaflet Structures

  • Simple leaf: one blade per petiole

    • Example: American beech, Fagus grandifolia (NJL)

  • Compound leaf: two or more leaflets per petiole

    • Example: Mockernut hickory, Carya tomentosa (NJL)

  • Pinnately lobed vs palmately lobed (leaf blade lobes)

  • Pinnately compound vs bipinnately compound

  • Rachis: the central axis of a compound leaf

  • Petiole: stalk attaching leaf to stem

  • Leaflet: individual units of a compound leaf

Common Leaf Types Illustrated

  • Simple leaf examples:

    • American beech (Fagus grandifolia) – simple, alternate

  • Lobed patterns:

    • Pinnately lobed (e.g., white oak, Quercus alba)

    • Palmately lobed (e.g., Florida maple, Acer floridanum)

  • Compound leaves:

    • Pinnately compound: leaflets arranged along a central rachis (e.g., mockernut hickory, Carya tomentosa)

    • Even pinnate vs odd pinnate (terminal leaflet present or absent)

    • Bipinnately compound (twice divided leaflets) – examples include Aralia spinosa (devil's walking stick) and Albizia julibrissin (mimosa)

    • Palmately compound: leaflets originate from a common point (e.g., red buckeye, Aesculus pavia)

    • Trifoliately compound (trifoliate) – Toxicodendron radicans (poison ivy)

Quick Reference: Simple vs Compound and Related Questions

  • When you’re unsure, ask: alternate or opposite? simple or compound?

  • Use multiple features together (leaf arrangement, leaf type, petiole, lobing, bark, fruit) to confirm identity

Representative Examples (NJL indicates included in notes sequence; references may be local)

  • Alternate, simple leaves: American beech (Fagus grandifolia) – NJL

  • Opposite leaves: Red maple (Acer rubrum) – NJL

  • Whorled leaves: Southern catalpa (Catalpa bignonioides) – NJL

  • Simple leaves with lobes: White oak (Quercus alba) – pinnately lobed

  • Palmately lobed leaves: Florida maple (Acer floridanum)

  • Compound leaves: Mockernut hickory (Carya tomentosa) – pinnately compound

  • Bipinnately compound: Aralia spinosa (devil's walking stick); Albizia julibrissin (mimosa)

  • Palmately compound: Red buckeye (Aesculus pavia)

  • Trifoliately compound: Poison ivy (Toxicodendron radicans)

Practical Notes for Lab and Field Work

  • Labs focus heavily on field identification skills; field safety and appropriate clothing emphasized

  • Practice is essential for building confidence in identification

  • Use dichotomous keys and morphology to support identifications

References to Figures and Diagrams in Lectures

  • Several pages refer to diagrams showing leaf margins, midribs, petioles, rachises, leaf types, and arrangements; review these visuals to reinforce terminology

Summary of Core Concepts

  • Dendrology combines taxonomy and silvics to understand woody plants

  • Taxonomy involves identifying, classifying, and naming plants based on morphology and other traits

  • Silvics describes how species respond to environmental factors (drought, shade, wind, etc.)

  • Accurate tree ID relies on integrating multiple characteristics (leaves, arrangement, bark, fruits, growth form, habitat)

  • A wide range of online resources and field guides are available to support identification and study