Alfalfa

Medicago sativa L.
Alfalfa is the most widely used perennial, cool season agronomic legume, and is adapted to many regions and uses. It is palatable for livestock but can cause bloat if not managed carefully.
Alfalfa can have very deep tap roots and a woody crown. There are different types of root systems with different types of alfalfa. The Flemish type has a narrow crown, taproot, and few lateral roots; Siberian has a deep set crown and widely branching roots; variegated types can have roots and crowns like either Flemish or Siberian, or intermediate. Creeping-rooted types have some ability to spread from rhizomes that grow horizontally from primary roots. Shoots may survive as independent plants. Alfalfa crowns are deeper set than most other legumes (except for sweet clover), which increases winter hardiness and survival.
Each alfalfa shoot develops many branches. Flemish types have erect stems and wider leaves, while Siberian types have finer, less upright stems and narrower leaves. Each leaf has three leaflets with finely toothed margins from midway to the point of the leaflet. Multi-foliate types may have more than three leaflets on each leaf.
Flowers form from buds at the base of branches, which continue to grow. Up to twenty flowers are attached to a stalk. Flower colour varies with the type of alfalfa. Flemish: purple; Siberian: yellow; variegated types: purple, blue, green, cream, or yellow. Alfalfa is cross-pollinated and leaf cutter bees are often required to achieve successful pollination. Seeds per pod vary from 3 to 10, depending on the type of alfalfa.