plants

[yeoman]

clover like plant of the pea family with three-lobed leaves

[woofgang]

vetch

[New Forester]

Almost all vetches have more leaflets, so it can't be that. Not just clover itself? There are quite a few other clover-like plants which have three leaflets. I can find: Medick Fenugreek Melilot Birds'-foot trefoil (looks like five leaflets though, as it has a pair of leaf-like stipules too) Restharrow Several other trefoils, such as hop trefoil. Seedling broom. In fact technically none of these have "lobed" leaves, but they are "ternate", divided into three separate leaflets -- perhaps not an important difference in your context?

[Newt]

Clover http://www.perspective.com/nature/plantae/dicots.html "Pea Family (Fabaceae) Pea family members seem to be everywhere in San Francisco Bay Area grasslands. The family includes the Acacia trees found both in and out of cultivation; shrubs such as Lupine (left), Broom, and Gorse; as well as the herbacious Vetch and Clovers. Pea fruit grow in a their distinctive pod shape; the flowers of the Pea family are typically distinctive as well. The flower has a banner petal above, two wing petals on either side, and a keel consisting of two fused petals below. The keel is often hidden between the wing petals, as in the Lupine (Lupinus nanus) flower shown here, in which the wings of the flower to the left of the stem were pulled down to reveal the keel." Newt