Also Known As
Prostrate Water Hyssop
This tiny yellow-flowered native creeping herb is often overlooked by most Floridians. I must have seen this little fella a hundred times, not knowing exactly which species it was. Then, I remember the first time that I really took the time to sit with this cute little herb. It was at Colt Creek State Park on a plant walk with my friend Mycol Stevens, and I made up my mind to key it out later that week with a sample of it in hand. Well, it turned out to be a Mecardonia species, procumbens to be specific. Thanks again to Prof. Wunderlin's keys in his comprehensive book on Florida's wild plants, "A Guide to the Vascular Plants of Florida." One note of interest... in Mexico, where this plant is known as Metatera, the whole plant is traditionally boiled and placed on external wounds to heal them. Oh, one more thing, certain butterflies like to nectar at the flowers.
MEDICINAL USES - WOUNDS: Here’s a quote form “Ethnomedicinal Application of Mercardonia procumbens,” an online article published by the Center for Health Sciences, National Polytechnic Institute in Mexico: The plant is “traditionally used to heal all kinds of wounds. The whole plant is boiled in one liter or water. The infusion water is taken while the wound is external, the affected part is [also] washed and [the] boiled plant is placed [in a compress and applied] externally. This ethnobotanical application is repeated until the wound is healed completely.” This was told by a traditional herbalist “in the countryside [town] of San Miguel Regla, municipality of Huasca de Ocampo, Hidalgo,” Mexico,  where the plant is known as Metatera. 
NATIVE TO: “Tropical and subtropical areas of the Americas.”  Alabama, Arizona, Louisiana, New Mexico, Texas, and scattered counties in Florida. It has become naturalized across much of the warmer parts of the globe. Here in Florida, in scattered counties across Florida, mostly in central or far southern parts of the state.
HABITAT: Riparian. Shaded open, moist woodland edges.
DESCRIPTION: An small, low, annual or perennial herb, sprawling to 16” wide.
- STEMS: Square.
- LEAVES: “Light green, fleshy, opposite, toothed, and have pinnate venation.”
- FLOWERS: Yellow, half inch long, tubular, “2 joined upper lobes, 3 lower lobes, and a brown-lined throat” 3 bracts at the base.
RELATED SPECIES: Here in Florida, another native Mecardonia grows wild, along with two subspecies, M. acuminata. These are commonly known as Axilflowers.
Moist woodland edges
 Atlas of Florida Plants
 Ethnomedicinal Application of Mercardonia procumbens, Center for Health Sciences, National Polytechnic Institute [online article]
 swbiodiversity.org; W. J. Hayden [photo: stems lying on gray board]