Page 138 - Ultimate Visual Dictionary (DK)

PLANTS
SIMPLE LEAF SHAPES
Leaves Subacute apex Acuminate
apex

LEAVES ARE THE MAIN SITES OF PHOTOSYNTHESIS (see pp.
138-139) and transpiration (water loss by evaporation)
in plants. A typical leaf consists of a thin, flat lamina
(blade) supported by a network of veins; a petiole (leaf
stalk); and a leaf base, where the petiole joins the
stem. Leaves can be classified as simple, in which
CHECKERBLOOM the lamina is a single unit, or compound, in Entire Entire
(Sidalcea malviflora) margin margin
which the lamina is divided into separate
leaflets. Compound leaves may be pinnate, with pinnae (leaflets)
on both sides of a rachis (main axis), or palmate, with leaflets
arising from a single point at the tip of the petiole. Leaves can
be classified further by the overall shape of the lamina, and
by the shape of the lamina’s Cuneate
base Cordate
apex, margin, and base. Apex
base
GENERAL LEAF PANDURIFORM LANCEOLATE
FEATURES Croton Sea buckthorn
(Codiaeum variegatum) (Hippophae rhamnoides)

COMPOUND LEAF SHAPES
Terminal
pinna
(leaflet)
Midrib
Lamina
(blade)
Emarginate
apex
Margin
Rachis
(main axis of
pinnate leaf)

Pinna
(leaflet)
Lateral
vein
Petiolule
(lea flet
stalk)

Lamina base
Petiole (leaf stalk) Petiole
(leaf stalk)
Leaf base

Sweet chestnut ODD PINNATE
(Castanea sativa) False acacia
(Robinia pseudoacacia)

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