Which weed is known for its distinct heart-shaped leaves and bright yellow flowers?

The weed known for its distinct heart-shaped leaves and bright yellow flowers is indeed Oxalis. This plant, often referred to as yellow wood sorrel, typically features clover-like trifoliate leaves that can appear heart-shaped. The bright yellow flowers have a unique appeal and are a signature characteristic of this species.

In addition to its visual characteristics, Oxalis thrives in many environments, often appearing in lawns and gardens, where it can become invasive if not managed properly. Its ability to spread and establish in various conditions can pose competition to turfgrass, making it important to identify for effective management.

The other options, such as Purslane, Prostrate Spurge, and Knotweed, do not feature the same leaf and flower characteristics as Oxalis. Purslane has thick, succulent leaves and yellow flowers but lacks the heart-shape that defines Oxalis. Prostrate Spurge has a different leaf structure and brings a different type of inflorescence, while Knotweed displays a more herbaceous growth with distinct jointed stems and different leaf shapes. Understanding the distinguishing features of various weeds is crucial for effective pest management in turfgrass environments.