Leaf or leaflet shape

The (plan) shape of a simple or unifoliolate leaf, or for divided (compound) leaves this refers to the shape of the leaflets. Note that the description of leaf shape is at best approximate, given that there exists a full range of variation between each idealised shape (e.g. broadly ovate may approximate orbicular, and narrowly ovate, linear) making interpretations somewhat subjective. Further complications arise from variation between individuals of a taxon, within an individual specimen, and in the case of compound leaves, between individual leaflets. Users should take a relatively broad interpretation of leaf shape, and enter the most commonly observed condition(s). When leaves/leaflets are deeply toothed or lobed, leaf/leaflet shape is approximated by a line drawn about the apices of each tooth/lobe.

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Ovate or lanceolate

Shaped like a longitudinal section through an egg and broader below the middle. Lanceolate leaves are narrowly ovate.

Triangular

With three sides and broadest below the middle.

Trullate

Kite shaped (rhomboid), broader below the middle, with the two lower sides equal and shorter than the two upper.

Elliptic

Oval in section, symmetrical about the middle (like a squashed circle).

Orbicular

Circular, or nearly so.

Linear

Very narrow in relation to length (length:width ratio greater than 10-15) and sides roughly parallel.

Filiform

Extremely narrow in relation to length (width is negligible), appearing thread-like.

Subulate

Narrow in relation to length and tapering gradually to a fine point at the apex (awl-shaped).

Oblong

Longer than wide by a few to several times (length:width ratio up to 10) and with sides parallel or almost so.

Rhombic

An oblique four sided shape, broadest about the middle, with approximately equal sides and lateral obtuse angles.

Obtriangular

With three sides and broadest above the middle.

Obtrullate

Kite shaped (rhomboid), broadest above the middle, with the two lower sides equal and longer than the upper.

Obovate or clavate or oblanceolate

Egg-shaped or  club shaped, sometimes narrowly so (oblanceolate) and broadest above the middle.

Spathulate

Spoon shaped, broadest above the middle and tapering to the point of attachment.