Pea Family Fabaceae

Formerly known as Leguminosae, this cosmopolitan family of 13,000 species contains the legumes vital food plants, such as peas, beans, lentils, soybeans, peanuts, alfalfa, and liquorice. There are two kinds of flower produced by species in the Fabaceae: regular whereby parts of the flower are similar in size and shape and irregular whereby parts of the flower are of varying shapes and lengths. Sixteen species are found in the Arctic, belonging to five genera: the milk-vetches, Astragalus, liquorice-roots, Hedysarum, beach peas, Lathyrus, lupines, Lupinus, and oxytropes, Oxytropis. All have irregular flowers composed of five sepals and five petals that vary in size and shape. The upper and largest petal is called the "banner" petal; two similar, lateral petals are the "wing" petals; and the lower, boat-shaped petal, called the "keel," is actually two fused petals. The ten stamens are oddly shaped as well nine are united, while the tenth grows freely. The fruits are called legumes and resemble a typical garden pea pod.

Many plants in the milk-vetch genus, Astragalus, are poisonous, but their degree of toxicity is linked to the soil type in which they grow. In fact, members of several genera in the pea family are commonly called "locoweeds". Certain species that grow on soils rich in selenium absorb the element and concentrate it in their tissues. When grazing animals eat the plant, it can cause neurological disorders. Members of some genera are naturally poisonous, containing locoine, a chemical that causes animals to go "loco" or "crazy" they lose muscle control, stagger around, and collapse in death.

Five Astragalus species occur in the Canadian Arctic. Alpine milk-vetch, A. alpinus, grows in low mats with creeping stems. The leaves bear white hairs underneath that lay almost flat against the surface; all grow in the same direction. The flowers are a pale bluish-violet colour and the black or brown fruits are hairy. Richardson's milk-vetch, A. richardsonii, is named for the surgeon-naturalist, John Richardson, of the Franklin Expedition. It is found only on the western islands of the Arctic Archipelago. Its flowers are colourful; the banner and wing petals are white with conspicuous green veins, while the keel is purple. Its dark red legumes are 2 cm long and somewhat translucent when full-grown, appearing slightly inflated and bladder-like.

Liquorice-roots, Hedysarum spp., are also called sweet-vetch, because most of the species have sweet-tasting, edible roots. Liquorice-root, H. alpinum, possesses fleshy roots that, when cooked, taste similar to baby carrots. The Inuit dig up these roots, peel away the outer covering and eat them raw, boiled, or roasted. The roots are a favourite among grizzly bears a bear will excavate hundreds of square metres of earth to feed on them. Liquorice-root grows in sand and gravel, often near river banks and lake shores. Its 10–20 pink or pale purple flowers grow in slender spikes; the seed pods are flat and have three to five transparent, oval sections, each containing a seed. In comparison, northern sweet-vetch, or wild sweet pea, H. mackenzii, has sweetly scented, bright magenta flowers that are much longer than those of H. alpinum. Starkly contrasting the sweet, edible roots of the liquorice root, John Richardson reported the northern sweet-vetch to be poisonous.

Another deadly, but attractive, plant is the arctic lupine, Lupinus arcticus. Even though its seeds resemble peas, they are lethally toxic. Its flowers are blue and white; its distinct leaves are palmately compound and bear soft, downy hairs underneath. The arctic lupine is endemic to the Arctic Cordillera.

Silvery oxytrope, Oxytropis arctobia.
The oxytropes, Oxytropis spp., have flowers that are arranged in head-like clusters atop leafless stems. Their leaves are pinnately compound and arise from a stocky tap root. Aside from their naked flower stems, oxytropes can be distinguished from the milk-vetches by examining the keel petals those of Oxytropis are tipped with a sharp tooth. The arctic oxytrope, O. arctica, is ubiquitous on the dry soil and open tundra of the Central Arctic islands, where it is endemic. Its flowers are sweetly scented and dark purple; a distinct white marking on the banner petal probably functions to guide their primary pollinators, bumblebees, as they come in for landing on the lower keel petal. Arctic oxytrope is similar to silvery oxytrope, O. arctobia, but lacks the silver-haired upper leaf surfaces of the latter species. Maydell's oxytrope, O. maydelliana, the most widespread member of this genus, is characterized by its shaggy calyx and legumes the shagginess results from long, black and white, hairs. Its flowers are pale yellow and grow in groups of five to seven on a short spike.

 
Maydell's oxytrope, Oxytropis maydelliana. Oxytropes can be distinguished by the "tooth" on their keel petals.