Leaf Morphology Flashcards
Reflexed
Bent or curved backward or downward
Alternate
One leaf borne per node; leaves spiral around twig
Obovate
Widest point is above the middle, L:W <2
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Lobed
A leaf with distinct projections from the midrib with individual inside veins
Simple leaf
An undivided or uninterrupted leaf blade (uninterrupted main vein(s) )
Oblanceolate
Widest point is above the middle, L:W >3
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-ulate
suffix for diminutive size
(first syllable of base word + suffix)
Reniform
Simple kidney-shaped leaf
Acuminate
Leaf apex shape, prolonged point
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Scurfy
Leaf covered with small scalelike particles
Peltate
Round leaf, with the stem attached near the center of the lower surface rather than the margin
e.g. nasturtium
Spine
Modified sharp, pointed leaf
Opposite
Two leaves per node; leaves opposite each other on the twig
Petiolule
Stalk of a leaflet
Linear
Widest point is at the middle, elongated leaf, L:W >5
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Dentate
Toothed margin (think: mountain shape)
Petiole
Leaf stalk
Crenate
scalloped margin
Teeth
Small indentations
Pinnatifid
A leaf with a blades divided into narrow lobes and with sinuses extending more than halfway to the midrib
Spinose
Margin baring small spines
Thorn
Modified sharp pointed branch
Pubescent
Leaf with a hairy surface
Sinus
On a leaf, a space or indentation between two lobes or teeth
Rugose
Wrinkled–typical leaves of the mint family
Decompound
Leaves more than once pinnately compound
Twice pinnately compound
Leaves twice pinnately compound (pinnately compound leaflets arranged pinnately on a main elongated axis)
Acute
Leaf apex shape, pointed
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Lanceolate
Widest point is below the middle, L:W >3
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Zonation
Markings on the leaf, usually circular in pattern
Axillary bud
Bud at the base of any leaf, indicates the base of a petiole vs a stem (which does not have a bud)
Prickle
Sharp outgrowth of epidermis or bark, occures at internodes
Cordate
Leaf base shape, notched
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Internode
The segment of the stem between nodes
Rachis
Main axis of a compound leaf of inflorescence from which leaflets or flowers are borne
Compound leaf
Leaf blade divided into segments
Tuberous root
A modified lateral root, enlarged to function as a storage organ
Viscid
Leaf covered with sticky or resinous secretion
Palmate compound
Compound leaf with all leaflets arranged at the apex of the petiole
Cuneate
Leaf base shape, pointed
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Obtuse
Leaf apex shape, rounded
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Rotund
Leaf base shape, rounded
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Ovate
Widest point below the middle, L:W <2
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Blade
Broad, expanded part of the leaf
Entire
Smooth margin
Leaflet
Photosynthetic division of a compound leaf
Dwarf shoots
Leaves arranged on lateral shoot, shoot is < 1”
Whorled
Three or more leaves per node
Node
One of the spots upon a stem where buds occur
Verticillate
Another term for ‘whorled’
Oblong
Widest point is at the middle, elongated leaf with nearly parallel sides, L:W 3-5
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Pinnately compound
A compound leaf with leaflets arranged on opposite sides of one elongated axis
Succulent
Thick fleshy tissue adapted to water storage
Attenuate
Leaf base shape, prolonged point
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Variegated
The presence of two or more colors in the leaves, petals, or other parts of plants
Visual difference between thorn and spine
A thorn occures at nodes between the stem and leaf where there would normally be a bud that would break into a branch.
A spine occures outside of the bud or branch.
Retuse or Emarginate
Leaf apex shape, notched
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Procumbent
Spreading along the ground but not rooting at the nodes
Clasping leaf
Leaf whose base partially or completely surrounds a stem
Pin shoots
Leaves arranged on lateral shoot, shoot is ≥ 1”
Maculation
Spotted coloration
Decussate
Adjacent pair of leaves is rotated about 90°
Elliptic
Widest point is at the middle, L:W <2
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Glaucous
Leaf covered with a whitish powder or waxy coating
Stipule
One of a pair of leaf-like appendages often found at the base of the petiole
Sessile
Leaf attached directly to the stem
Serrate
saw-tooth margin
Glaucous
Color of a leaf (especially on the underside) has changed due to a waxy covering, causing it to look grayish, blueish, or whiteish
Rugose
Wrinkled leaf texture
Plicate
Accordian-like wrinkles