2. Tradescantia L. (spiderwort)

(Anderson and Woodson, 1935)

Plants perennial, the roots fibrous or more commonly thickened and somewhat fleshy to tuberlike. Stems usually unbranched. Leaf blades linear to lanceolate, flat above the base. Inflorescences 1 to several, terminal and sometimes axillary, the flower clusters subtended by 1 or 2 bracts indistinguishable from the foliage leaves. Flowers actinomorphic. Sepals 3, narrowly ovate to elliptic. Petals 3, equal and lacking stalklike, narrowed bases, broadly obovate to elliptic. Stamens 6, the filaments with dense, spreading hairs. Staminodes absent. Fruits 4B8 mm long, ovoid, 3-locular. Seeds 3B6 per capsule, 2B3 mm long, oblong to ovoid and somewhat flattened with a depression on 1 side, the surfaces undulate to bluntly several-ribbed. 50B60 species, North America to South America.

Several species of Tradescantia are cultivated as ornamentals and are used industrially to test for the presence of radiation and some chemical mutagens (Tucker, 1989). The most commonly used plants, however, have resulted from various past interspecific hybridizations by plant breeders involving T. ohiensis, T. subaspera, and T. virginiana. These are often referred to as ATradescantia -andersoniana,@ a name that has not been typified and therefore has not been published validly. Naturally occurring hybrids also may be found on occasion in Missouri, thus the key below will not work well for every plant encountered in the field.