Family: Pea [Fabaceae (Leguminosae)]

Acacia

Anthyllis

Arachis

Astragalus

Cercis

Cicer

Colutea

Coronilla

Cullen

Cytisus

Dorycnium

Galega

Genista

Gleditsia

Glycine

Glycyrrhiza

Hippocrepis

Hymenocarpus

Laburnum

Lathyrus

Lens

Lotus

Lupinus

Medicago

Melilotus

Onobrychis

Ononis

Ornithopus

Oxytropis

Paraserianthes

Phaseolus

Pisum

Robinia

Scorpiurus

Securigera

Senna

Sesbania

Spartium

Tetragonolobus

Thermopsis

Trifolium

Trigonella

Ulex

Vicia

Vigna

Wisteria

The PEA FLOWER STRUCTURE All flowers in the Pea Family have five petals, and five fused sepals behind them, forming a bi-symmetric flower. There is the large banner or standard at the top, with two smaller wings below and within these two keels. This flower doesn't always look as though it has five petals. There are two inner petals called the keel, which are paired into a flattened-cup shape which generally hide both stigmas and stamens. Two further paired petals called the wings are on either side of the keel forming a cowl around the keel (sometimes hiding the keel). Finally a much larger petal usually nicked in the middle, called the banner, is held aloft. Sometimes the flowers look as though they only have two petals, but closer inspection involving the fingers always reveals five. This flower is that of Lucerne. IDENTIFYING FEATURES OF THE PEA FAMILY How many leaflets are in each pinnate leaf (if present) Whether the leaflets of a pinnate leaf are in opposite pairs, or are alternate. The length and breadth of leaflets Whether the leaflets have minute prickles at the tip, or not. Whether there are two auricles where the leaves attach to the stem. The presence or absence of a chevron shaped marking on the leaves. The presence (or absence) of any tendrils (by which it clambers) Whether the tendrils (if present) are split into two. And if the tendrils are split into two, whether they are equal in length. Whether the wings and keel of the flower are equal in length, or which is the longer. The colour(s) of the flowers. Whether the stems have wings, or not. Whether the seed pods are spiralled, curved or nearly straight. The presence or absence of hairs, and where. an AMINO ACID and a NON-PROTEINOGENIC AMINO ACID Canavanine, a non-protein amino acid (NPAA), is present in the seeds of many plants belonging to the Pea family. It is very similar to a genuine amino acid, Arginine, that is part of many proteins. Note that the main difference is the substitution of an oxygen atom into the carbon chain and necessary rearrangement of the nitrogen double-bond. In the human body Canavanine is able to masquerade as Arginine for the body has no mechanism to differentiate it from Arginine, so it too becomes (wrongly) incorporated into proteins. This can disrupt the ability of the synthesised protein to do its intended job. Thus Canavanine is poisonous in the human body and is one of the reasons why the seeds of plants from the pea family are often very poisonous. [Arginine is shown for comparison only, as far as the Author knows it does not occur in the Pea Family].