Trifolium Genus clover Fabaceae

Trifolium repens.flowers.Patrick J. Alexander @ USDA-NRCS PLANTS Database

Trifolium repens.flowers.Patrick J. Alexander @ USDA-NRCS PLANTS Database (Accessed 4/2014).

Trifolium is a genus of low herbs, stipules present.  Trifoliums, and many other legumes (plants in the family Fabaceae), have root nodules that are symbiotic with Rhizobium bacteria. These bacteria have the capacity to take nitrogen (N2) from the air and convert it to NH4 (ammonium), which the plant can then use to make amino acids which are linked together to form proteins. This process is known as nitrogen fixation (Raven et al. 1986).

Leaves alternate, 3-parted (trifoliate), leaf stalk with swollen base (pulvinus) that assists in orienting the leaf surface, margin finely toothed (serrulate). 

Nitrogen Fixing root Nodules on Clover.commons.wikimedia.org

Nitrogen Fixing root Nodules on Clover.commons.wikimedia.org (Accessed 3/2017).

Flowers white to red or yellow, bilaterally symmetrical, pea-slower-shaped, calyx tubular strongly 2-lipped, with 5 pointed lobes; petals 5, the uppermost (banner, standard, or flag) largest and outermost, often folded over the side petals but with the outer end pointing upward, the 2 lateral petals (wings) similar to each other, the 2 lowest petals fused into a keel and enfolding the pistil and stamens; corolla soon drying but persistent. Flowers in small, usually dense heads 

Trifolium repens fruit.© Mike Crewe.Cape May Plant & Wildlife Guide.capemaywildlife.com

Trifolium repens fruit.© Mike Crewe.Cape May Plant & Wildlife Guide.capemaywildlife.com (Accessed 3/2017).

Fruit a short pod (legume) often enfolded within persistent calyx, 1-6 seeded. 

Origin: all ours from Eurasia or Europe.