Look closely at your lawn. You might see this guy, threeflower ticktrefoil, AKA Desmodium triflorum, staring up at you.
It is a tiny plant, a member of pea family,and a weedy one at that. It creeps along the ground so low that it's pretty much impervious to mowing. The tiny pea-like pods have velcro-like hairs that stick to a passing animal or person as a means of distributing its seeds.
Threeflower ticktrefoil can be an annual or perennial, apparently depending on the annual distribution of rainfall — annual in places where there is a rainy season, perennial where rainfall is generally spread throughout the year. It has compound leaves with three rounded leaflets, which are smooth above, hairy below. The stems are hairy and can have many branches, effectly creating a dense mat. They also root where nodes contact the ground. The flowers are pea-like in shape and range in color from blue to purple to pink to red.
Threeflower ticktrefoil is a native of Southeast Asia, China, Australia and has become naturalized to tropical and subtropical places around the globe, including Guatemala and Mexico. In parts of the Pacific, threeflower trefoil is considered an invasive.
In the United States, it's found in Florida, Louisiana and Hawaii. It's found over most of the Sunshine State, particularly the Peninsula as far south as the Keys but the Florida Exotic Plant Pest Council has not deemed it to be invasive.
Despite its weediness, threeflower ticktrefoil does have its uses. In Australia, it is considered good forage for grazing cattle. It's also has been used as a ground cover to prevent erosion and as a "green manure" to improve soil. The United States Golf Association called it the southern equivalent of clover, and said it made "patches of excellent turf in lawns and on many of the golf courses." That was in 1925.
Medicinally, its been used as an antiseptic and expectorant. It's been used to treat diarrhea and dysentery, as a mouthwash and externally to treat wounds and skin problems. The weirdest "fact" we came across was a Wiki article that said the Drug Enforcement Agency wanted to criminalize threeflower trefoil because of a chemical, DMT, which is found in the plant as well as many others. The article has since been edited to remove the DEA and DMT reference.
Other names: threeflower trefoil, three flower beggarweed, creeping tick trefoil and tropical trefoil. It is a member of Fabaceae, the pea family