leaves Flashcards
basic parts
blade or lamina
lamina/blade
flat part of leaf.
petiole
base/stalk of a leaf… if not present, known as a sessile leaf (unstalked)
veins
thickened bundles of vascular tissue of the leaf
hydaphodes
open veins in a leaf, not plugged in the leaf.
examples: guttation from hydathodes, releasing water
stipules
small leaf at base of big leaf, can be estipulate if no stipule present
abscission layer
layer of cells at base of petiole, weakens and breaks during leaf drop season.
simple leaves
have only one blade…
reticulate venation
common for dicots, complex network of veins, some examples are palmate, pinnate,
parallel venation
parallel veins
dichotomous venation
dichotonous veination veins splitting
compound leaves
more than one blade, hard to distinguish compound leaves from a whorl: look for the petiole, look for axillary bud
pinnately compound
petiole continues as a rachus (extension of the petiole, contains leaflets)
alternate leaves
opposite leaves
whorled leaves
three types of tissue in leaves
epidermis, mesophyll, vascular tissue
epidermis of leaves
- single layer of cells all over the leaf,
- epidermis has no chlorophyll
- cells secrete cutin, which is used to make a cuticle on the surface of the leaf
three types of epidermal cells
typical
guard cell - swell up when taking in water, includes stomata
gland cell - secretes something, have different shapes