1. Cleome hassleriana Chodat (spider flower, pink queen)

C. spinosa Jacq., misapplied

C. houtteana Schltdl., misapplied

Pl. 333 j, k; Map 1558

Stems 30–150 cm tall, unbranched or sparsely branched above, densely glandular and hairy. Leaves palmately compound with 5 or 7 leaflets, densely glandular and sparsely hairy, the petioles 6–15 cm long. Stipules relatively stout golden brown spines 1–4 mm long. Leaflets 3–10 cm long, elliptic to oblanceolate, narrowed or tapered to a sharply pointed base and tip, the margins entire or shallowly toothed, the undersurface sometimes with sparse, short prickles similar to the stipular spines along the midvein. Inflorescences to 35 cm long, relatively dense. Bracts 1–4 cm long, 0.5–2.0 cm wide, simple, short-stalked to nearly sessile, ovate, tapered to a sharply pointed tip, densely glandular. Flower stalks 4–6 cm long, glandular. Sepals fused at the very base, 6–7 mm long, narrowly lanceolate, densely glandular and sometimes also sparsely hairy. Petals all oriented to one side of the flower, similar in size and shape, 18–28 mm long, 6–8 mm wide, abruptly narrowed to a stalklike base 6–12 mm long, pink to purple, rarely white. Glandular disk fleshy, conical, 1–3 mm long. Stamens with the filaments 3–4 cm long, the anthers 7–9 mm long, linear. Gynophore relatively short at flowering (0.5–0.9 cm) but elongating rapidly as the fruit matures to 3–8 cm long. Fruits 2–7 cm long, 3–4 mm wide, linear, usually slightly constricted between seeds, glabrous. Seeds 1.6–2.0 mm in diameter, the surface appearing wrinkled or warty, dark brown with lighter-colored warts and faint concentric lines. 2n=20. August–October.

Introduced, uncommon and sporadic in the southern half of the state (native of tropical America, mainly Brazil; widely planted and often escaping throughout the eastern U.S.). Banks of streams and rivers and rarely glades; also railroads, roadsides, and open, disturbed areas.

This showy species is popular in gardens throughout the world and often is sold under the name C. spinosa. There are many varieties available. The plants are very colorful and popular with hummingbirds. The common name spider flower comes from the long, waving stamens that somewhat resemble spider legs. Cleome hassleriana has been cultivated and has escaped from gardens in Missouri for a long time. Through the courtesy of Dr. Hugh Iltis of the University of Wisconsin at Madison, a specimen accessioned at the National Natural History Museum in Paris came to light that demonstrates this. In June 1848, the French botanist Auguste Trécul (see the introductory chapter on the history of Missouri botany in Yatskievych, 1999) collected a plant on the bank of the Mississippi River near Ste. Genevieve.