Sinus
Organization Chart
Broad leaves
Leaves
opposite
Leaves
simple
Leaves lobed
(Maple)
Sinus “V”
Sinus “U”
The indentation between the lobes (or fingers) of the leaf is called the sinus.  Look for a rounded shape, like a “U” (sugar Maple, left) or a sharp angle, like a “V” (red maple, left).