Ranunculus trichophyllus, commonly known as threadleaf crowfoot or thread-leaved water-crowfoot, is an herbaceous plant that can be either annual or perennial. It is native to a variety of aquatic environments including slowly-flowing streams, ponds, and lakes, often found at elevations up to 9,800 feet. This species is widespread across Europe, Asia, and North America, with a presence in diverse locations such as the United States, the Himalayan region, and even the high-altitude lakes of Mount Everest. The plant typically has a delicate appearance, with daisy-like white flowers that have a yellow center and five petals. Its segmented leaves are finely dissected and can photosynthesize underwater, which is a unique adaptation to its aquatic habitat.

Threadleaf crowfoot is valued for its ecological role in phytofiltration, as it has the ability to remove heavy metals from water, including arsenic. This makes it useful for bioremediation projects. In cultivation, it is appreciated for its delicate flowers and its ability to thrive in water gardens or natural ponds. It requires an aquatic environment to grow, with either standing or slow-moving water, and full sun to part shade. While it is not commonly used in traditional garden settings, it is an excellent choice for water features and can contribute to the ecological health of such environments. Care should be taken to manage its growth, as it can spread rapidly under ideal conditions.CC BY-SA 4.0