Which prostrate warm-season annual has bright-green leaflets, yellow flowers, and seeds with two stout spines resembling Texas longhorns?

• A. Puncturevine
• B. Knotweed, Prostrate
• C. Purslane, Common
• D. Poison Ivy

Answer: (A)

Recognizing a weed often comes down to a distinctive combination of features: growth habit, leaf type, flower color, and seed pods. This weed is a prostrate warm-season annual that lays flat across the turf, and it shows bright-green leaflets arranged along a stem, with yellow flowers. The seeds form in spiny capsules that carry two stout spines, a striking clue that looks like Texas longhorns. That combination—low-growing habit, yellow flowers, and the two-spined seed pods—points directly to puncturevine, a weed well known for its sharp, tire-puncturing seeds. The other plants don’t match this exact set of traits: prostrate knotweed lacks the distinct bright-green leaflets with yellow flowers and the long-spined seed pods; purslane has fleshy stems and different leaves and flowers; poison ivy is a perennial with a different leaf arrangement and no spiny seed capsules.