BALL MUSTARD, Neslia paniculata (L.) Desv. 1, plant with flowers and fruit; 2, stem and leaves; 3, taproot and lower leaves; 4, flower. Annual or biennial, reproducing by seed. Stems branched above, slender, hairy, yellow-green, erect, 1 to 2 feet (30 to 60 cm) tall. Leaves on stems alternate, 1 to 2-1/2 inches (2.5 to 6.3 cm) long, hairy, arrow-shaped. The leaf base nearly encloses the stem and the tip is blunt to pointed. Lower leaves broad, narrowed at the base with a round tip. Flowers yellow, 4 petaled, produced on racemes 2 to 10 inches (5 to 25 cm) long. Seed pods round, about 1/8 inch (3 mm) in diameter, gray-brown with definite netlike surface markings. Each pod contains 1 seed, which is hard to separate from pod. Seeds yellow, about the size of white clover seeds. Found especially in grain fields and waste places.