Legume family (Fabaceae)
The legume family has about 12 000 species worldwide (current counts are much higher, over 19 000), mostly herbs and some shrubs and trees. The taproot carries nodule bacteria: they turn free nitrogen of the air into compounds the plant can use and receive food from the plant in return, so the soil becomes richer in nitrogen after legume crops. Leaves are often compound with stipules and alternate on the stem. The flower is irregular and bisexual; the corolla is butterfly-like: a large “standard” on top, two “wings” at the sides and a fused pair of petals below forming the “keel”. There are 10 stamens: 9 with fused filaments and 1 free; one pistil; the fruit is a legume (pod). Meadow clover (25–50 cm, three leaflets, head-like inflorescence), camelthorn (deep root reaching groundwater), mung bean, chickpea, common bean, soybean, lentil and peanut (from South America; after pollination the flower stalk bends down and the pod ripens underground) belong here. White acacia, the Japanese pagoda tree and honey locust are ornamental trees. The Red Book of Uzbekistan has the most species from this family (about 60) — mainly Astragalus, Oxytropis and Hedysarum (sweetvetch).
Observation: sprout a few bean or pea seeds in damp cotton wool; on the roots of a grown seedling (or wild clover/pea) find small nodules with a lens; if a flower is available separate the standard and the keel. Safety: do not eat raw beans — they are eaten cooked; children with peanut allergy should not handle peanuts; do not put wild legumes (acacia seeds, astragalus) in the mouth; wash hands.