LEAVES Flashcards
Leaf morphology can be characterized based on:
Type of leaves
Venation
Phyllotaxy
Leaf shape
Base
Margin
Apex
Monocot Leaf ADAPTATIONS
Ligule
Auricle
collar extension of the sheath curving around the stem; membranous, hairy or absent
Auricle
appendage that surrounds the stem at the junction of the blade and sheath
Auricle
angle of the petiole
axil
the main axis of a compound structure. It can be the main stem of a compound leaf
rachis
a leaf-like part of a compound leaf
leaflet or foliole
dicot leaves that do not have petioles
sessile leaf
petioles that are attached to the middle of the blade;
Peltate leaves
sessile leaves that surround and are pierced by stems; e.g. include yellow-wort and thoroughwort
Perfoliate leaves
arrangement of veins
Venation
veins running parallel with one another (monocot)
Parallel venation
Netted types
Pinnately veined leaves
Palmately veined leaves
one primary vein (midvein) which is included within an enlarged midrib
Pinnately veined leaves
several primary veins fan out from the base of the blade
Palmately veined leaves-
Type of venation found in lower vascular plants. (E.g. Horsetail) One nerve is enough to sustain the blade.
Univernous
3 primary veins.
Ternate-netted
Always branching into two veins. (E.g. Gingko)
Dichotomous
Arrangement of leaves along the axis of the stem.
Phyllotaxy
Two leaves; in pairs. Oriented in one plane. In some species, can be oriented in different planes.
Oppositive leaves
Opposite leaves attached at right angles to the adjacent pairs of leaves, in one node.
Decussate
Three or more leaves in the node
Whorled leaves
One leaf per node, Spiral arrangement.
Alternate leaves
Leaves are all originating from the stem. Circular arrangement of leaves or of structures resembling leaves.
Rosette
To facilitate gas exchange between the inner parts of leaves, stems, and fruits, plants have a series of openings known as
stomata
stomates only on the upper epidermis
Floating leaves
NO stomates
Submerged leaves
shape of upper epidermis
(Elongated cells)
shape of lower epidermis have guard cells.
(spherical, loosely arranged)
Upper (Elongated cells) and lower (spherical, loosely arranged) epidermis both have guard cells in dicots
true
Layers of mesophyll in dicots
Palisade parenchyma: Upper epidermis Spongy parenchyna: Lower epidermis
Vascular tissues in leaves
veins
Flexible courtesy of the collenchyma tissues
Midrib
Mesophyll layer is not well differentiated into palisade and spongy layers
monocot leaves
contains bulliform cells
monocot leaves
Depending on the environment, some species develop their own adaptations
true
Desert plants adaptations
thick and reduced leaves
stomata opens only at night time
thick waxy layer
Modified Leaves
cotyledons
tendrils
colored bracts
insect trapping
spines
storage leaves
absorptive leaf
reproductive leaf
leaf hooks
stipules
expanded petiole
flower pot leaves
expanded petiole
First leaves produced by a germinating seed. Often contain a stored food to help the seedling become established. Contains some food reserves for stock-up of the seedling. Once the plant is well-established, it will shed off the _____.
cotyledons
Blade of leaves or leaflets are reduced in size; allows plant to cling to other objects.
tendrils
Petal-like leaves to attract pollinators.
colored bracts
Possessed by certain plants that live under nutrient-poor conditions.
insect trapping
Protection against herbivory. As blades, they do not have any surface for transpiration.
spines
having large vacuoles to retain water in halophytes
storage leaves
A lot of aquatic plants do not have a developed root system. Hydrilla adapted for their leaves to have the role of absorption underwater.
absorptive leaf
leaves that produces a lot of buds for asexual reproduction
reproductive leaf
help the plant crawl upward
leaf hooks
photosynthetic leafy outgrow
They may range from quite leaf-like to small and inconspicuous structures. They are typically regarded as a component of a normal flowering plant’s anatomy.
stipules
petiole that maximizes photosynthesis
expanded petiole
will catch all the falling leaves and falling plant debris from the canopy.
Will also retain water used to decay with the decayed plant debris which will provide the plant the nutrients it needs to survive.
flower pot leaves
