3.4: Leaves Flashcards
- first embryonic leaves
- storage organ
- give a lot into leaves during germination
cotyledon
leaves shout be…
flat & thin ; alive & differentiated
simple leaf originate from single point
palmately lobed
simple leaf originate from midrib at separate points
pinnately lobed
compound leaf: leaflets attached to single point in petiole
palmately compound
compound leaf: leaflets attached to rachis
pinnately compound
venation common in angiosperms
- pinnately
- anastomosing (everywhere)
netted/reticulate venation
venation common in monocots
- side to side
- base to tip
parallel venation
in ferns: the first set of veins in each pinna or lobe points towards the apex
anadromous
in ferns: the first set of veins in a pinna in a basal direction
catadromous
lack of petiole replace by…
leaf sheath
w petiole
petiolatew
w/o petiole
sessile
w/ stipule
stipulate
w/o stipule
exstipulate
orientation of leaves in space
phyllotaxy
cluster of similar organs from same point
fascicled
two different planes
decussate
same plane
distichous
what makes leaf waterproof?
cutin
- 1 or more layers of elongated chloranchyma
- specialized in light absorption
- closely packed
palisade mesophyll
- several layers of irregularly-shaped parenchyma
-surrounds vascular bundles
spongy mesophyll
- collenchyma cells for support
- protection of vascular tissues
bundle sheath
- mass of fibers above/below
- in large veins for additional support
bundle sheath extension
for support:
- slender coiling structure
- derived from branch
leaf tendril
for support:
- tip into tendril
- sense objects; grow around them
apex tendril
for support:
compact assemblage of overlapping and spirally arranged leaf sheaths
pseudostem
for storage:
- thick/fleshy
- favors water conservation
succulents/ thickened leaves
for storage:
- large epiphytic ferns trap organic debris
- becomes canopy soil= can store water externally
pocket/nest leaves
for protection:
- red conical structure
- revealed as leaf starts to lengthen
united stipules
for protection:
- swelling on petiole
- permits leaf movement
pulvinus
for attraction:
modified/specialized leaf in the inflorescence, standing below partial peduncles, pedicels, or flowers
colored bracts
for reproduction:
mitosis at meristems along the leaf margins produce tiny plantlets that fall of and grow independently into mature plants
marginal notches
for buoyancy:
bulbous stalks that contain air-filled tissues
bulbose petiole
for traps:
- lamina is tubular rather than flat
- secretes digestive fluid
pitcher-like apex
