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FNA | Family List | FNA Vol. 22 | Commelinaceae

3. Tradescantia Linnaeus, Sp. Pl. 1: 288. 1753; Gen. Pl. ed. 5; 139, 1754.

Spiderwort, wandering-Jew, spider-lily, éphémères [for John Tradescant, gardener to Charles I of England]

Rhoeo Hance; Setcreasea Schumann & Sydow; Zebrina Schnizlein

Herbs, perennial. Roots thin or tuberous. Leaves spirally arranged or 2-ranked; blade sessile or rarely petiolate [petiolate]. Inflorescences terminal or terminal and axillary, pairs of cymes, cymes sessile, umbel-like, contracted, subtended by spathaceous bract; bract similar to leaves or differentiated, margins distinct; bracteoles persistent. Flowers bisexual, radially symmetric; pedicels very short or well developed; sepals distinct (basally connate in T. zebrina), subequal; petals distinct (rarely connate basally), white to pink, blue, or violet, equal, rarely clawed; stamens 6, all fertile, equal; filaments bearded or glabrous; ovary 3-locular, ovules (1--)2 per locule, 1-seriate. Capsules 3-valved, 3-locular. Seeds 2 per locule (1 in T. spathacea); hilum oblong to linear; embryotega abaxial to lateral. x = 6--8, probably others.

Species ca. 70 (30 in the flora): neotemperate and neotropical.

The species described by E. Anderson and R. E. Woodson Jr. (1935) are narrowly defined and typological. Nevertheless, they are recognizable entities even if some of them may prove eventually unworthy of specific rank. Where specific problems have been recognized, they are noted in the discussions at the end of the species.

Tradescantia species hybridize freely when growing together (E. Anderson and R. E. Woodson Jr. 1935). My observations in the field and garden tend to confirm this. The definite or probable hybrids are listed after the species. The list is almost certainly incomplete. The questionable records are based on uncertain determinations. The record of a possible hybrid between T. ohiensis and Callisia rosea (as Cuthbertia rosea), cited by Anderson and Woodson, is omitted: the specimens appear to be merely gracile plants of T. ohiensis. Some native species are occasionally cultivated, although most garden plants seem to be hybrids of T. virginiana and other species (E. Anderson 1952). They are usually sold as Tradescantia ´ andersoniana (an invalid name) followed by a cultivar epithet.

SELECTED REFERENCES

Anderson, E. 1954. A field survey of chromosome numbers in the species of Tradescantia closely related to Tradescantia virginiana. Ann. Missouri Bot. Gard. 41: 305--327. Anderson, E. and K. Sax. 1936. A cytological monograph of the American species of Tradescantia. Bot. Gaz. 97: 433--476. Anderson, E. and R. E. Woodson Jr. 1935. The species of Tradescantia indigenous to the United States. Contr. Arnold Arbor. 9: 1--132. Hunt, D. R. 1980. Sections and series in Tradescantia. American Commelinaceae: IX. Kew Bull. 35: 437--442. MacRoberts, D. T. 1980. Notes on Tradescantia (Commelinaceae) V. Tradescantia of Louisiana. Bull. Mus. Life Sci. Louisiana State Univ. 4: 1--15. Sinclair, C. 1967. Studies on the Erect Tradescantias. Ph.D. dissertation. University of Missouri.


1 Flowers subsessile; petals clawed, claws connate at least basally; stamens epipetalous.   (2)
+ Flowers distinctly pedicellate; petals neither clawed nor connate; stamens free.   (6)
       
2 (1) Leaves 2-ranked, bases oblique, cuneate; blade usually variegated; sepals connate basally   30 Tradescantia zebrina
+ Leaves spirally arranged, bases symmetric, rounded to broadly cuneate; blade not variegated; sepals distinct.   (3)
       
3 (2) Leaves narrowly lanceolate, apex acuminate; stamen filaments glabrous   29 Tradescantia leiandra
+ Leaves lanceolate-elliptic to oblong-elliptic or ovate, apex obtuse to abruptly acute-apiculate; stamen filaments glabrous or bearded.   (4)
       
4 (3) Leaves oblong-elliptic to lanceolate-elliptic, mostly 7--15 cm; peduncle (3.5--)4--13 cm; leaves usually purplish violet   28 Tradescantia pallida
+ Leaves oblong-elliptic to ovate, mostly 3--7 cm; peduncle 1--5(--6) cm; leaves green.   (5)
       
5 (4) Filaments and ovary glabrous; flowering June to October   26 Tradescantia brevifolia
+ Filaments bearded, ovary densely bearded; flowering February to May   27 Tradescantia buckleyi
       
6 (1) Sprawling to decumbent plants rooting at nodes; leaves lanceolate to lanceolate-elliptic or lanceolate-oblong to ovate-lanceolate or ovate-elliptic.   (7)
+ Erect or ascending plants, rarely rooting at nodes; leaves mostly linear-lanceolate to lanceolate-oblong.   (8)
       
7 (6) Leaves lanceolate-elliptic to ovate-lanceolate, to 5  2 cm; cyme pairs usually 1--2 per shoot; bracts all or mostly foliaceous, occasionally reduced   24 Tradescantia fluminensis
+ Leaves lanceolate-oblong to ovate-elliptic, to 10  3.5 cm; cyme pairs 2--4 per shoot; bracts, especially those of axillary inflorescences, usually reduced   25 Tradescantia crassula
       
8 (6) Inflorescences all or chiefly axillary.   (9)
+ Inflorescences terminal, commonly terminal and axillary.   (10)
       
9 (8) Inflorescences pedunculate in axils well proximal to shoot apex, enclosed in boat-shaped spathes; leaves glabrous; flowers white   23 Tradescantia spathacea
+ Inflorescences mostly sessile in axils of distal leaves; boat-shaped spathes absent; leaves usually arachnoid-villous; flowers blue to purple   22 Tradescantia crassifolia
       
10 (8) Distal leaf blades wider than opened, flattened sheaths.   (11)
+ Distal leaf blades equal to or narrower than opened, flattened sheaths.   (14)
       
11 (10) Pedicels 1--1.7 cm; proximal leaves petiolate; stems frequently flexuous; plants flowering mainly May--Sep   1 Tradescantia subaspera
+ Pedicels (1.5--)2--3.2 cm; proximal leaves narrowed directly into sheath; stems not flexuous; plants flowering mainly Feb--May.   (12)
       
12 (11) Sepals 9--16 mm, ± inflated, eglandular-pilose; flowers usually deep blue, purple, or rose-red   4 Tradescantia ernestiana
+ Sepals 6--12 mm, not inflated, glandular-pilose or mixed glandular- and eglandular-pubescent; flowers usually white or pale pink to pale lavender.   (13)
       
13 (12) Leaves not glaucous; capsules 8--10 mm   2 Tradescantia edwardsiana
+ Leaves ± glaucous; capsules 6--8 mm   3 Tradescantia ozarkana
       
14 (10) Sepals glabrous or with eglandular hairs only (very rarely a few minute glandular hairs at base).   (15)
+ Sepals pubescent with glandular and often eglandular hairs.   (21)
       
15 (14) Sepals glabrous (or with apical tuft of eglandular hairs or a few minute glandular hairs at base).   (16)
+ Sepals covered with eglandular hairs.   (18)
       
16 (15) Stems 5--18 cm; pedicels, sepal bases often with minute glandular hairs; petals 10 mm   20 Tradescantia wrightii
+ Stems 15--115 cm; pedicels glabrous; sepals glabrous or with apical tuft of eglandular hairs; petals usually 0.8--20 mm.   (17)
       
17 (16) Plants distinctly glaucous; leaves 5--45 cm, arcuate, forming acute angle with stem (also see Tradescantia occidentalis var. scopulorum)   5 Tradescantia ohiensis
+ Plants not at all to slightly glaucous; leaves 4--11 cm, straight, forming nearly right angle with stem   6 Tradescantia paludosa
       
18 (15) Bracts saccate at base, blades reduced, densely, minutely velvety .   7 Tradescantia gigantea
+ Bracts not saccate at base, blades well developed, sparsely to densely pilose.   (19)
       
19 (18) Flowering stems 2--7 cm (elongating to 20 cm in fruit), pilose to villous; sepals purple or rose-colored (rarely pale green), not inflated; rocky prairies   8 Tradescantia tharpii
+ Flowering stems 5--50 cm, glabrous to pilose or hirsute; sepals various; habitat various but rarely rocky prairies.   (20)
       
20 (19) Roots (1.5--)2--4 mm thick; stems commonly glabrous proximal to inflorescence; sepals usually ± inflated; ne and Appalachian   9 Tradescantia virginiana
+ Roots 1--1.5(--2) mm thick; stems usually pilose to hirsute throughout; sepals not inflated; se   10 Tradescantia hirsutiflora
       
21 (14) Pedicels 0.8--1 cm, glandular-puberulent; sepals 4--6 mm; petals 9--12 mm; hilum much shorter than seed   21 Tradescantia pinetorum
+ Pedicels (0.8--)1--6 cm, glandular- or eglandular-pubescent; sepals (4--)6--16 mm; petals (6--)10--19 mm; hilum as long as seed.   (22)
       
22 (21) Sepals with mostly glandular pubescence.   (23)
+ Sepals with mixture of glandular, eglandular pubescence.   (25)
       
23 (22) Internodes and leaves glabrous   11 Tradescantia occidentalis
+ Internodes pubescent (rarely glabrous in Tradescantia roseolens)   (24)
       
24 (23) Pedicels 1--2.8 cm; roots all thin and fibrous; South Carolina to Florida and Alabama   12 Tradescantia roseolens
+ Pedicels 2.5--4.5 cm; at least some roots thick and tuberous; Texas   13 Tradescantia pedicellata
       
25 (22) Stems, leaves completely glabrous; plants glaucous; sepal hairs mainly glandular (also see Tradescantia roseolens).   11 Tradescantia occidentalis
+ Stems, leaves usually sparsely to densely pubescent, if glabrous then sepal hairs mainly eglandular; plants usually not glaucous (somewhat glaucous in T. roseolens); sepal hairs various.   (26)
       
26 (25) Stems densely arachnoid-pubescent; roots thick, brownish-tomentose.   (27)
+ Stems variously pubescent but not arachnoid-pubescent; roots various but not brownish-tomentose.   (28)
       
27 (26) Stems erect or ascending, unbranched or sparsely branched, 30--105 cm   14 Tradescantia reverchonii
+ Stems spreading, diffusely branched, 10--30 cm.   15 Tradescantia subacaulis
       
28 (26) Plants diffuse, spreading; stems much branched .   16 Tradescantia humilis
+ Plants erect or ascending; stems unbranched or sparsely branched.   (29)
       
29 (28) Sepal hairs mainly eglandular, glandular hairs few, inconspicuous   10 Tradescantia hirsutiflora
+ Sepal hairs mainly glandular or eglandular, glandular hairs numerous, conspicuous.   (30)
       
30 (29) Sepals puberulent, hairs all less than 1 mm; roots relatively thin, 0.5--1(--2) mm thick   12 Tradescantia roseolens
+ Sepals pilose-puberulent, longer hairs 1.5--6 mm; roots relatively stout, 1--3 mm thick.   (31)
       
31 (30) Plants bright green; stems, leaves usually glabrous   17 Tradescantia bracteata
+ Plants dull green; stems, leaves usually pubescent (rarely glabrescent).   (32)
       
32 (31) Stems (2--)15--40 cm; pedicels 1.5--3.5 cm; leaves, bracts puberulent, usually sparsely to densely pilose, margins ± densely ciliolate   18 Tradescantia hirsuticaulis
+ Stems 2--10 cm; pedicels (2--)4--6 cm; leaves, bracts pilose but not puberulent, margins sparsely ciliate   19 Tradescantia longipes

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