Easily mis-identified as : Common Vetch (Vicia sativa) which is the tallest at 1m variously pink to purple, rarely white or yellow, but with the wings being a darker shade than the banner.

There are three sub-species of Common Vetch :

• Narrow-leaved Vetch (Vicia sativa ssp. nigra) which is the plant depicted on this page - the shortest of all at 0.75m but often procumbent. Strongly heterophyllous (with two distinctively different shaped leaves) it has narrow leaves with the upper leaves being much and abruptly narrower than the lower leaves. Crucially, un-like Common Vetch, all five petals the same shade. It has black seed pods (rather than the brown of Common Vetch) that split open in a spiral.
• Common Vetch (Vicia sativa ssp. sativa) a quite rare relic of cultivation (for fodder) and at 1.5m taller than the others and with bicoloured flowers. Often mistaken for ssp. segetalis below.
• Common Vetch (Vicia sativa ssp. segetalis) to 1m tall with all leaves being much the same size and with bicoloured flowers. Sometimes cultivated for fodder.

Slight resemblance to : Bush Vetch (Vicia sepium) but that has dull-purple flowers rather than bright purple-pink.

Not to be semantically confused with: Narrow-Leaved Everlasting-Pea or Narrow-leaved Bird's-foot Trefoil [plants all belonging to the same Pea Family as Narrow-leaved Vetch].

No relation to : Narrow-Leaved Pepperwort, Narrow-Leaved Helleborine, Narrow-leaved Hawkweed, Narrow-leaved Michaelmas Daisy, Narrow-Leaved Water-Plantain, Narrow-Leaved Ragwort, Narrow-leaved Ash or Narrow-leaved Lupin [plants with similar names].