Week 2 - Plant Morphology Flashcards
Morphology
- The physical form or gross external structure of plants
Taproot
- Large primary root that extends straight down and tapers gradually
- Example: carrot, Taraxacum officinale (dandelion), Arctium lappa (burdock)
Fibrous Root
- Many roots extending down from the stem
- Example: Allium sativa (garlic), Epilobum sp. (willow herb plant)
Adventitious Root
- Arises from non-root tissue (usually from a stem)
- Example: blackberry
Stems
- Framework of a plant that supports leaves, flowers, and other structures
- A conduit for exchange of water, nutrients, and sap
- Can act as a place for storage of fuel
- Can be an area of photosynthesis in green stems
Internal Stem Feature - Epidermis
- Outer layer of wax-coated cells
Internal Stem Feature - Cortex
- Tissue between the epidermis and the phloem
Internal Stem Feature - Vascular Tissues
- Carry water, nutrients, and photosynthates through the plant
Internal Stem Feature - Vascular Tissue - Xylem
- Carries water and minerals from the roots upward through the plant
Internal Stem Feature - Vascular Tissue - Cambium
- Single-celled layer of diving tissue that creates the xylem on one side and the phloem on the other
Internal Stem Feature - Vascular Tissue - Phloem
- Carries sugars down through the plant
Internal Stem Feature - Pith
- The center of the stem that can be woody and dense, chambered, or hollow
Dicotyledon Stem
- Has two leaves when it sprouts
- Can be herbaceous or woody
Monocotyledon Stem
- Has one leaf when it sprouts
- Example: grass
External Stem Feature - Terminal Bud
- The bud at the tip of the stem
External Stem Feature - Lateral Bud
- Bud that grows from leaf axils on the side of a stem
External Stem Feature - Bud Scale
- Modified leaves that protect the bud
External Stem Feature - Naked Bud
- A bud without scales
External Stem Feature - Leaf Scar
- The mark left where a leaf was attached
External Stem Feature - Bundle Scar
- The marks within the leaf scar where the vascular bundles passed through
External Stem Feature - Terminal Bud Scale Scar
- The area where the previous year’s terminal bud scales were attached
- Shows the growth pattern from year to year
Modified Stem - Bulb
- Underground storage leaves attached at a base
- Example: tulips, daffodils
Modified Stem - Corm
- Short, thickened underground stem with scales that form a tunic
- Solid rather than having rings (like an onion) or cloves (like garlic)
- Example: crocus
Modified Stem - Crown
- A compressed stem with leaves above and roots below
- Example: Taraxacum officinale (dandelion)
Modified Stem - Stolon
- Horizontal, above-ground runner that sets down roots or generates a plantlet at its nodes
- Example: strawberries, Potentilla anserina (silverweed)
Modified Stem - Rhizome
- Horizontally growing underground stems
- Example: Mahonia spp. (Oregon grape), zingiber, Curcuma longa (turmeric), Hydrastis canadensis (goldenseal)
Modified Stem - Twining Stems
- Used for climbing
- Some twist clockwise, some counter-clockwise
- Example: Lonicera sempervirens (honeysuckle)
Modified Stem - Tuber
- An enlarged rhizome containing stored food
- These structures have “eyes,” or modified buds dotted around them
- Example: potato
Modified Stem - Tuberous Stem
- A storage stem with buds only on the “up” side
External Leaf Feature - Blade
- The flattened part of the leaf
External Leaf Feature - Petiole
- Stalk of the leaf
External Leaf Feature - Margin
- Leaf edge
- May be lobed, toothed, smooth, etc.
External Leaf Feature - Stipule
- Leaf-like appendages at the base of the leaf
Arrangement of Leaves on the Stem - Opposite
- On opposite sides of the stem at the same level
- Example: Mentha spicata (spearmint)
Arrangement of Leaves on the Stem - Alternate
- Leaves at alternating levels on the stem (staggered)
- Example: Trifolium pratense (red clover)
Arrangement of Leaves on the Stem - Whorl
- Three or more leaves at the same level of the stem
- Example: Gallium aparine (cleavers)
Arrangement of Leaves on the Stem - Rosette
- A spiral pattern of attachments around the stem
Arrangement of Leaves on the Petiole - Simple
- Blade is one continuous unit
- Example: Acer sp. (maple)
Arrangement of Leaves on the Petiole - Palmately Compound
- Multiple leaflets radiating from a central point
- Example: Aesculus hippocastanum (horse chestnut)
Arrangement of Leaves on the Petioloe - Pinnately Compound
- Leaflets arranged on both sides of a common rachis (stalk)
- Example: Fraxinus angustifolia (narrow-leafed ash)
Arrangement of Leaves on the Petiole - Double Pinnately Compound
- Common sub stalks and stalks
- Example: Acacia sp.
Flowers - Pistil
- Female organ
- Made up of stigma, style, and ovary
Flowers - Pistil - Stigma
- Often sticky projection that receives pollen
Flowers - Pistil - Style
- Tissue between the stigma and the ovary
Flowers - Pistil - Ovary
- Contains ovules (unfertilized immature seeds) and embryo sacs
Flowers - Stamen
- Male organ
- Made up of anther and filament
Flowers - Stamen - Anther
- Pollen-producing organs
Flowers - Stamen - Filament
- Stalk supporting the anthers
Flowers - Petals
- Collectively form the corolla
Flowers - Corolla
- Made up of a collection of petals
Flowers - Sepals
- Protective, leaf-like coverings for the flower bud
- Collectively form the calyx
Flowers - Calyx
- Made up of a collection of sepals
Flowers - Receptacle
- Base of the flower
Flowers - Pedicel
- The stalk of an individual flower in an inflorescence
Inflorescence
- Arrangement of flowers on a stem
Inflorescence - Single
- Solitary
- Example: Crocus vernus (crocus)
*Inflorescence - Spike
- Type of raceme with flowers that do not have a pedicel
- Example: lavender
*Inflorescence - Raceme
- Unbranched, indeterminate with pedicellate flowers along the stalk
- Example: Actaea racemosa (black cohosh)
*Inflorescence - Corymb
- Unbranched, indeterminate
- Flat-topped or convex
- Outer pedicels are progressively longer than inner ones
- Example: Achillea millefolium (yarrow)
*Inflorescence - Umbel
- Raceme with short axis and multiple floral pedicels of equal length that appear to rise from a common point
- Example: dill
*Inflorescence - Cyme
- A determinate inflorescence
- Inner flowers opening first
- Example: Symphytum officinale (comfrey)
*Inflorescence - Composite
- Made up of bunches…
- Example: Echinacea purpurea
