Often leaf shapes do not exactly fit into one category, but are in between two different shapes. Also, leaves may change shape during their development or as a result of enviromental conditions.
Orbiculate = rotund, orbicular, circular, or nearly so (as in sheild-like) with the petiole attached at the edge.
Peltate = rotund, orbicular, circular, or nearly so, with the petiole attached to the centre of the leaf blade.
Elliptic = with the shape of an ellipse: about twice as long as broad.
Oval = broadly elliptic, the width being considerably more than half the length.
Ovate = about one and a half times as long as broad with the widest point not in the middle (as in elliptic), but towards the end, and with the petiole attached to the broad end.
Obovate = the same as ovate, but with the petiole attached to the narrow end.
Lanceolate = lance-shaped, four to six times as long as broad, with curved sides and pointed ends, larger at one end than the other, and with the petiole attached to the broad end.
Oblanceolate = the same as lanceolate, but now with the petiole attached to the narrow end.
Oblong = nearly rectangular with rounded corners, about two or three times as long as broad, and with the petiole attached to one of the shorter ends.
Linear = at least eight time as long as broad.
Rhombic = diamond-shaped with the petioles attached to one of the sharper angles.
Cordate = heart-shaped with the length greater than the width, and the petiole attached to the indentation at the base.
Obcordate = the same as cordate, but now with the petiole attached to the sharp end.
Reniform = kidney or bean shaped, with a rounded apex, and with the width greater than the length, and the petiole attached to the broad, basal indentation of the blade.
Sagittate = arrowhead-shaped with the petiole attached to the indentation.
Hastate = like sagittate, but with basal, divergent lobes.
Subulate = awl-shaped, slender, and tapering from the base upward.
Cuneate = (cuneiform) wedge-shaped with the petiole attached to the sharp angle.
Deltoid = an equilateral triangle with the petiole attached to the middle of one of the sides.
Obdeltoid = like deltoid, but now with the petiole attached to one of the angles.
Spathulate = (spatulate) spatula-shaped.