Herbs, erect or ascending, rarely rooting at nodes. Roots (1.5--)2--4 mm thick, fleshy. Stems 5--35 cm; internodes glabrous or occasionally distal internodes sparsely puberulent. Leaves spirally arranged, sessile; blade linear-lanceolate, 13--37 ´ 0.4--2.5 cm (distal leaf blades equal to or narrower than sheaths when sheaths opened, flattened), apex acuminate, glabrous or occasionally puberulent. Inflorescences terminal and (rarely) axillary; bracts foliaceous, well developed, not saccate, sparsely to densely pilose. Flowers distinctly pedicillate; pedicels 1.2--3.5 cm, eglandular-pilose or puberulent; sepals ± inflated, 7--16 mm, uniformly eglandular-pilose; petals distinct, blue to purple, occasionally rose or white, broadly ovate, not clawed, 1.2--2 cm; stamens free; filaments bearded. Capsules 4--7 mm. Seeds 2--3 mm. 2n = 12, 24.
The records from the northern parts of the range of Tradescantia virginiana may all represent garden escapes (E. Anderson 1954). The uncertainty about the records from Arkansas and Mississippi reflects the difficulty in identifying some specimens. The specimens in question come from areas in which T. hirsutiflora (but not T. virginiana) has been recorded (E. Anderson and R. E. Woodson Jr. 1935). The exact geographic boundaries between these putatively allopatric species are uncertain. D. T. MacRoberts (1980b) has made a useful contribution toward our knowledge of these species.
Perennial herb to 40 cm tall Stem: erect or ascending, seldom rooting at the nodes. Leaves: spirally arranged, 4 - 37 cm long, 0.5 - 1.5 cm wide, linear to lance-shaped with a pointed tip, the base wrapping around the stem to form a sheath. The blade width equals the circumference of the sheath. Inflorescence: terminal, seldom axillary, subtended by well-developed leaf-like bracts that are larger than the leaves and softly hairy. Flowers: borne on hairy stalks 1.2 - 3.5 cm long, with three sometimes inflated sepals 0.7 - 1.5 cm long and covered with nonglandular hairs, three blue to purple (sometimes rose or white) petals 1.2 - 2 cm long and not clawed, unattached stamens, bearded filaments, a thin style, and a head-like stigma. Fruit: a three-valved and three-chambered capsule, 4 - 7 mm long, containing six 2 - 3 mm long seeds.
Similar species: The Tradescantia species found in the Chicago Region can most easily be distinguished by the size of their leaves and presence or type of hairs on the sepals, flower stalks and bracts. Tradescantia subaspera leaf blades are wider than the sheaths (over 2 cm) and less than 10x as long as wide; the sepals and flower stalks are hairy. Tradescantia ohiensis leaf blades are as wide as or narrower than the sheath (less than 2 cm) and more than 10x as long as wide; the sepal tips are sometimes hairy and the flower stalks are hairless. Tradescantia bracteata leaf blades are as wide as or narrower than the sheath (less than 2 cm) and more than 10x as long as wide; the sepals and flower stalks are covered by a mixture of non-glandular and glandular hairs, but the bracts are hairless.
Flowering: mid May to July
Habitat and ecology: Rare in the Chicago Region, this species grows in oak woodlands and sandy prairies.
Occurence in the Chicago region: native
Notes: Spiderworts have leaf arrangements that resemble spider legs. This feature gave the plant its common name. The flowers of spiderworts open in the morning and then wilt into a jelly-like substance.
Etymology: Tradesecantia is named after John Tradescant (d. 1638), the gardener of King Charles I. Virginiana means "from Virginia."
Stems straight, erect, 0.5-4 dm at anthesis, glabrous or obscurely puberulent; lvs usually 2-4, elongate, glabrous or nearly so, 5-15 mm wide, rarely wider; bracts often wider and longer than the lvs; cyme terminal and usually solitary; pedicels 15-35 mm, sparsely pilose with eglandular hairs 1 mm; sep 10-15 mm, rather densely villous throughout with eglandular hairs 1-2 mm; pet blue or purple, 12-18 mm; 2n=12, 24. Moist woods and prairies; Me. to Pa., Mich., and Minn., s. to Ga. and Mo. Spring.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent but well distributed in the southern two thirds of the state, becoming less frequent to very rare in the northern counties. This is a woodland species and is rarely found in the open. It is usually found in dry clayey soil in white oak, white oak and black oak, and beech and sugar maple woods. White and rose colored forms are sometimes found and they persist under cultivation.