Morphoanatomy of Leaves Flashcards
any of the principal appendages of a vascular plant stem
leaf
usually borne laterally above ground and specialized for photosynthesis
leaf
Leaves are collectively called
foliage
Most leaves are usually green,
due to the presence of
chlorophyll
flattened portion of a leaf
blade/lamina
attaches the leaf to the stem
petiole/leaf stalk
small leaf-like growths near the base of the petiole
stipule
runs through the center of the blade and a continuation of the petiole which acts as the backbone
midrib
functions as a passage tube for liquids between the petiole and veins
midrib
acts as the framework of the leaf
and functions as a passage tube for liquids between the midrib and the blade
veins
edge of a leaf
margin
has only one leaf stalk, petiole
simple leaf
the leaf blade is completely divided, forming leaflets.
compound leaf
an extension of the petiole bearing
leaflets.
rachis
If rachis is absent, it is called
palmately compound (digitate)
if rachis is present, it is called
pinnately compound (pinnate)
The arrangement of veins and veinlets in leaves (Lamina)
venation
Main vein divided into various branches (veinlets) and form a net like structure.
reticulate
type of venation can be found in dicots
reticulate
all veins run parallel to each other and they do not form network
parallel
type of venation found in monocots
parallel
In this type of venation leaf have only one principal vein or midrib that give off many lateral veins which proceed toward margin and apex of lamina of the leaf and form
a network.
unicostate or pinnate in reticulate venation
many principal veins arising from the tip of petiole and proceed towards tip of lamina
multicostate or palmate in reticulate venation
types of multicostate venation in reticulate
multicostate divergent and convergent
Many principal veins arising from the tip of petiole, diverge from the
another toward the margin of leaf blade
multicostate divergent in reticulate venation
Many principal veins arising from the tip of petiole. At the base of leaf they are closely arranged but diverge from one another in middle part and converge towards the apex of leaf.
multicostate convergent in reticulate venation
only one principal vein that gives off
many lateral veins, which proceed toward the margin of leaf blade in a parallel manner but they do not have veinlets.
unicostate or pinnate in parallel venation
Having many principal veins arising from the tip of the petiole and proceeding upwards.
multicostate or palmate in parallel venation
types of venation included in multicostate venation in parallel venation
multicostate divergent
multicostate convergent
furcate venation
Many principal veins arising from the tip of petiole and diverge toward the margin of leaf. They donot divide into veinlets and do not form network.
multicostate divergent
Many principal veins arising from the tip of petiole run in a curved manner in lamina and converge towards the apex of leaf blades.
multicostate convergent
The veins branch dichotomously but the reticulum is not formed by
the finer branches.
furcate venation
arrangement of leaves on a stem
phyllotaxy
Plants that have only one leaf per node
alternate or spiral
the leaves alternate on each side of the stem in a flat plane
alternate
the leaves are arrayed in a spiral along the stem.
spiral
two leaves arise at the same point, with the leaves connecting opposite each other along the branch.
opposite
Leaves that stands at right angle to next upper or lower pair
decussate
Successive pairs of leaves stand directly over a pair in the same plane
superposed
More than two leaves at each node
whorled
occurrence of more than one type of leaves on the same plant.
heterophylly
Leaves of different forms and shape occur at different period or places on the same plant
developmental heterophylly
It is aquatic adaptation which is
commonly found in rooted emergent hydrophytes.
environmental heterophylly
submerged leaves differ from the floating and aerial leaves
environmental heterophylly
Due to habit mature leaves differ in their shape and incissions
habitual heterophylly
Leaves with a stalk or petiole
petiolate
A lamina without a petiole
sessile leaf
Small green appendages usually
found at the base of the petiole
stipules
If stipules are present in leaf it is
called
stipulated leaf
if stipule is absent then leaf is
called
exstipulated
a flattened leaf base (the sheath) partially or wholly clasps the
stem
sheathing
leaf appears to extend down the stem from the point of attachment, as if fused to the stem
decurrent
a leaf is sessile and clasps the stem for most, but not all, of its circumference
amplexicaul
the leaf is sessile with the base of the blade completely surrounding the stem
perfoliate
Two opposite leaves fuse basally, such that the blade bases of the fusion product completely surrounds the stem.
connate-perfoliate
boundary area extending along the edge of the leaf.
leaf margin
shape of the leaf tip
leaf apex
lowest part of a lamina that is near the petiole
leaf base
an extension of a vein
apical process
trichome cover
vestiture
term meaning without trichomes at all.
glabrous
leaves contain 3 tissue systems
dermal tissue (upper and lower epidermis)
ground tissue (palisade and spongy mesophyll)
vascular tissue (xylem and phloem)
These cells appear to be involved in
the rolling or folding inward of the leaf during drought. When water is plentiful, these cells are turgid (swollen with water) and the leaf is open.
bulliform cells
forms a coil to help the plant in climbing or support of weak stem
tendrils
reduced leaf that is usually modified for protection
bud scales
modified leaves that surround a group of flowers to attract pollinators
bracts
serve as protection to the plant and photosynthesis is carried out mainly by fleshy green stems
spines
most succulents have leaves modified for storing water
storage leaves
leaves of some succulents produce
adventitious plantlets which fall off the leaf and take root in the soil.
reproductive leaves
function as food storage organs during dormancy
bulb scales
