Our area is in the midst of a drought. In response to the lack of water many plants are stunted this season. While walking near Medicine Lake recently (Siskiyou County CA) I noticed a flowering yarrow plant that was only about six inches tall and a similarly dwarfed penstemon, also in bloom. Thus my first thought when I saw diminutive yellow flowers in a drying swale was that they were runty buttercups. When I looked closer I realized that the little yellow flowers were not stressed, but rather were lesser spearwort, a diminutive species belonging to the buttercup family.
Lesser spearwort (Ranunculus flammula) is amphibious (adapted to both land and water). This native, perennial can be found in the shallow water of lake margins, wet muddy shorelines, marshes, and wet meadows throughout Canada, west of the Rockies and across the northern states. As the water recedes lesser spearwort becomes terrestrial.
The lesser spearwort stems can be a couple centimeters in length to a foot or more. The plant often assumes a “creeping” appearance and roots at the stem nodes. The alternate leaves of lesser spearwort are basal and grow along the stem. Linear to lance shaped, the leaves have a long petiole. The bright yellow flowers are solitary and terminal on a stem stalk. Lesser spearwort flowers consist of five hairy sepals, five petals and multiple pistils and stamens. The petals are longer than the sepals.
The species name, flammula, comes from the Latin “flamma” and means “flame”. Perhaps the bright yellow flowers look like little flames in a sea of green. Or maybe the species designation refers to the fiery taste of this little plant. Toxins in the plant cause the peppery taste and can irritate the skin and mucous membranes.
Banewort and creeping spearwort are two other common names for this petite plant.