Tradescantia

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Tradescantia
Spiderwort Blue Flower 2.JPG
Tradescantia virginiana
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Commelinales
Family: Commelinaceae
Subfamily: Commelinoideae
Tribe: Tradescantieae
Subtribe: Tradescantiinae
Genus: Tradescantia
Ruppius ex L.[1][2]
Type species
Tradescantia virginiana L.
Sections
  • Austrotradescantia
  • Campelia
  • Coholomia
  • Corinna
  • Cymbispatha
  • Mandonia
  • Parasetcreasea
  • Rhoeo
  • Separotheca
  • Setcreasea
  • Tradescantia
  • Zebrina
Synonyms[3][2]

Tradescantia /ˌtrædɨˈskæntiə/,[4] the Spiderworts, is a genus of 75 species of perennial plants in the family Commelinaceae, native to the New World from southern Canada south to northern Argentina including the West Indies. Some species have become naturalized in various regions in Europe, Asia, Africa, Australia and assorted oceanic islands.[3]

They are weakly upright to scrambling plants, growing to 30–60 cm tall, and are commonly found individually or in clumps in wooded areas and fields. A number of the species flower in the morning and when the sun shines on the flowers in the afternoon they close, but can remain open on cloudy days until evening.

The three species of Wandering Jew, one native to eastern Mexico, also belong to the Tradescantia genus. Other names used for various species include Spider-lily, Cradle-lily, Oyster-plant and Flowering Inch Plant.

Description[edit]

The leaves are long, thin and bladelike to lanceolate, from 3–45 cm long. The flowers can be white, pink, or purple, but are most commonly bright blue, with three petals and six yellow anthers. The sap is mucilaginous and clear.

Taxonomy[edit]

Subdivision[edit]

Tradescantia fluminensis
(Austrotradescantia )
Tradescantia occidentalis
(Tradescantia: Virginianeae)
Tradescantia sillamontana
(Tradescantia: Sillamontanae)

In the 1980s David Hunt divided the genus into 8[5] (later 12)[6] sections, with the nominate section (Tradescantia) further subdivided into a further four series, this superseded an earlier system by Clarke (1881).[7] Hunt originally recognised 60 species of which over half (32) he placed in section Tradescantia. Hunt's original speciation is given here, as further circumscribed by Burns et al. (2011).[8] Enlarging the sections from eight to twelve added six further species (total 68). Within section Tradescantia he distinguished the American species (series Virginianae) from the three Mexican series (Tuberosae, Sillamontanae, Orchidophyllae). 'Type' here indicates Species typica. Numbering of sections refers to Hunt's original (1980) system as a cross check to his index. The renumbered sections from 1986 are given in italics, e.g. (1)(5).
Note 1: The place of T. schippii is uncertain. Hunt indicats it is included in section Zebrina, but Burns considers the section monotypic
Note 2: T. blossfeldiana as used by Hunt and Burns is now considered a synonym for T. cerinthoides. Hunt originally listed these as separate species. Hunt also listed T. potosina and T. nuevoleonensis as separate species, but the latter is now the accepted name, while T. subramosa and T. subtilis are now considered synonyms for T. maysillesii rather than separate species.[9]

Section Austrotradescantia (3)(7) D.R.Hunt. 5 species

(Brazil, Uruguay, N Argentina)

Section Campelia (1) (Rich.) D. R. Hunt 1 species

(Tropical America)

Section Coholomia (2)(6) D.R.Hunt 1 species

(Guatemala, El Salvador, S Mexico)

Section Corinna (2) D.R.Hunt 1 species

(S Mexico, Guatemala, Nicaragua and Costa Rica)

Section Cymbispatha (1)(5) (Pichon) D.R.Hunt 9 species

(Mexico to Bolivia and Brazil)

Section Mandonia (7)(11) D.R.Hunt 7 species

(Mexico: Durango)

Section Parasetcreasea (8)(12) D.R.Hunt 1 species

(Mexico: Chihuahua to Oaxaca)

Section Rhoeo (4) (Hance) D.R.Hunt 1 species

(Mexico (Yucatan), Belize)

Section Separotheca (6)(10) (Waterfall) D.R.Hunt 1 species

(Mexico: Durango)

Section Setcreasea (5)(9) (K.Schum. & Sydow) D.R.Hunt 5 species

(U.S.A.: Texas; Mexico: Chihuahua to Veracruz)

Section Tradescantia (4)(8) L. 32 species
Section Zebrina (3) (Schnizlein) D.R.Hunt. 1 species

(Mexico to Venezuela)
(*Tradescantia schippii D.R.Hunt.)

Incertae sedis

Nothospecies[edit]

  • Tradescantia × andersoniana W.Ludw. & Rohweder [12][13] Phylogenetically T. x andersoniana is situated within series Virginianae, as follows ( T. ohiensis × ( T. subaspera Ker Gawl. × T. virginiana L.)).[8]

Formerly placed here[edit]

Species[edit]

By 1998 Fadden listed 70 species.,[14] while currently The Plant List accepts 75.[15]

Etymology[edit]

The name of the genus honours the English naturalists John Tradescant the Elder (ca. 1570s – 1638) and John Tradescant the Younger (1608–1662).[16]

Distribution and habitat[edit]

The first species described, Virginia Spiderwort T. virginiana, is native to the eastern United States from Maine to Alabama, and Canada in southern Ontario. Virginia Spiderwort was introduced to Europe in 1629, where it is cultivated as a garden flower.

Conservation[edit]

The Western Spiderwort T. occidentalis is listed as an endangered species in Canada, where the northernmost populations of the species are found at a few sites in southern Saskatchewan, Manitoba and Alberta; it is however more common further south in the United States south to Texas and Arizona.

Cultivation[edit]

Though sometimes considered a weed, spiderwort is cultivated for borders and also used in containers. Where it appears as a volunteer, it is often welcomed and allowed to stay. A common cultivar group is derived from the naturally occurring interspecific hybrid (nothospecies) Tradescantia × andersoniana also referred to as 'Andersoniana Group'.[17] An example is 'Karminglut' ('Carmine Glow').[18]

Toxicity[edit]

Some members of the genus Tradescantia may cause allergic reactions in pets (especially cats and dogs), characterised by red, itchy skin. Notable culprits include T. albiflora (Scurvy Weed); T. spathacea (Moses In The Cradle); and T. pallida (Purple Heart).

Uses[edit]

Hoverfly at Tradescantia flower; note the blue stamen hairs

The cells of the stamen hairs of some Tradescantia are colored blue, but when exposed to sources of ionizing radiation such as gamma rays, the cells mutate and change color to pink; they are one of the few tissues known to serve as an effective bioassay for ambient radiation levels.[19]

References[edit]

  1. ^ Linnaeus Sp. Pl.: 288 (1753).
  2. ^ a b "Genus: Tradescantia L.". Germplasm Resources Information Network. United States Department of Agriculture. 2004-08-10. Retrieved 2011-03-20. 
  3. ^ a b Kew World Checklist of Selected Plant Families
  4. ^ Sunset Western Garden Book, 1995:606–607
  5. ^ a b Hunt, David R. (1980). "Sections and Series in Tradescantia: American Commelinaceae: IX". Kew Bulletin 35 (2): 437–442. JSTOR 4114596. 
  6. ^ a b Hunt, David R. (1986). "Campelia, Rhoeo and Zebrina united with Tradescantia: American Commelinaceae: XIII". Kew Bulletin 41 (2): 401–405. JSTOR 4102948. 
  7. ^ C B Clarke Commelinaceae. In A. & C. De Candolle Monogr. Phan. 3: 288, 113-324 (1881).
  8. ^ a b Jean H. Burns, Robert B. Faden, and Scott J. Steppan. Phylogenetic Studies in the Commelinaceae Subfamily Commelinoideae Inferred from Nuclear Ribosomal and Chloroplast DNA Sequences. Systematic Botany, 36(2):268-276. 2011. DOI 10.1600/036364411X569471
  9. ^ World Checklist of Selected Plant Families
  10. ^ "Tradescantia". Integrated Taxonomic Information System. Retrieved 2011-06-16. 
  11. ^ a b "GRIN Species Records of Tradescantia". Germplasm Resources Information Network. United States Department of Agriculture. Retrieved 2011-06-16. 
  12. ^ Feddes Repert. Spec. Nov. Regni Veg. 56: 282 (1954)
  13. ^ World Checklist
  14. ^ Faden, R. B . 1998 . Commelinaceae . Pp. 109 – 127 in The families and genera of vascular plants vol. 4 , ed. K. Kubitzki . Berlin : Springer
  15. ^ The Plant List
  16. ^ Quattrocchi, Umberto (2000). CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology. IV R-Z. Taylor & Francis US. p. 2697. ISBN 978-0-8493-2678-3. 
  17. ^ Floridata
  18. ^ Dave's Garden
  19. ^ Ichikawa, Sadao (1972). "Somatic Mutatiion Rate in Tradescantia Stamen Hairs at Low Radiation Levels: Finding of Low Doubling Doses of Mutations". The Japanese Journal of Genetics 47 (6): 411–421. doi:10.1266/jjg.47.411. 

Bibliography[edit]

Gallery[edit]

External links[edit]