Leaves of Flowering Plants Flashcards
How can leaves be classified
- Gross morphology
-mega/microphylls
-shape
-venation (arrangement of veins)
-attachment - Monocot/Dicot
- Type of environment
-xeric (dry)
-mesic (moderate)
-hydric (wet)
Foliage leaves morphology characteristics
-photosynthetic
-monocot or dicot
-growing conditions
-shape
-veration
Bracts
Usually small, scale-like leaves that subtend flowers or inflorescences. In other cases they are large, showy and contribute to the overall conspicuous ness of the inflorescence
Ex: flowering dogwood or Christmas poinsettia
Cataphylls
(Bud scales)
-thick cuticle which protects young leaves and buds during the winter from dedication and from herbivores.
Spines
Modified leaves
-non photosynthetic
-hard, dry
-protect surface of the plant from damage by herbivores as any damage leads to water loss!!!
Tendrils
Modified leaves or leaflets for support on other plants
Cotyledons
-seed leaves
-fleshy storage organs
-monocots have 1
-dicots have 2
-supply seedling with nutrients until the first foliage leaves develop
Stipules
Base of leaf appendages leaves
Small appendages that are found at the base of the petioles of the eudicot leaves.
Ligules
Collar of the leaf stalk that encircles the stems and the vase of the leaf blade in grasses.
Small membrane or fringe of hairs that extends up the stem of a grass from where the lead blade separates from the sheath.
Carnivorous leaves
Leaves are traps to capture animals
-usually live in acidic habitats where nitrogen is rare
-are photosynthetic but supplement nutrients from animals
Alternate, opposite and whirled leaf arrangement (Phyllotaxy)
Only one leaf occurs at a node
Two leaves occur at the same node
More than 2 leaves originating from the same node
Simple leaves
Compound leaves
Whole leaves
Odd pinnate (terminal leaf present), even pinnate, palmately lobed (leaflets starched by one point)
Where do leaves develop from
Leaf primordia near apical meristem
Epidermis of leaves contains what
Cuticle, stomata, hair
Fundamental tissue of leaves contain what kind of cell
Mesophyll
Difference from eudicotyeldon and monocotyledon leaves internal anatomy
-dicot leaves have very dense structure with little room
-monocot leaves have larger vacuoles
Hydrophytes adaptations
Aquatic
-thin cuticle
-non functional or absent stomata
-loosely arranged cells in mesophyll
-large air spaces
-reduced Schlerenchyma
-small vascular bundle
Xerophytes leaf adaptations
Dry, high sunlight
-water storage tissue
-thick cuticle (hydro dermis protects mesophyll)
-spines
-lots of Schlerenchyma
-leaf hairs (trichomes)
-very small leaves to reduce the surface area and reduce water loss
-sunken stomata
Angiosperm leaves are ______
Megaphylls
Leaves usually have _____ growth meaning they grow to a certain size
Determinant
Epigeous development
Hypogeous development
Two cotyledons may be pulled out of the seed coat and emerge
above the ground
Or remain below the soil surface
If the petiole is present the leaf is said to be….
If the petiole is missing the leaf is…
A leaf possessing stipules is _____; with no stipules it is ______
Petiolate
Sessile
Stipulate
Exstipulate
Compound leaves
A leaf in which the blade is divided into several segments. Each segment are known as leaflets
Venation
The pattern the major veins in the leaf blade create
-parallel
-reticulate or net veined
-palmate