Lepidium heterophyllum

Lepidium heterophyllum, (Smith's cress or Smith's pepperwort), is a species of flowering plant in the mustard family which is native to parts of western Europe, growing in shingle banks, wasteland or cultivated fields.

Lepidium heterophyllum
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Brassicales
Family: Brassicaceae
Genus: Lepidium
Species:
L. heterophyllum
Binomial name
Lepidium heterophyllum
Synonyms[2]
  • Crucifera lepidioides E.H.L.Krause
  • Lepidium corrigioliforme Pau
  • Lepidium smithii Hook.
  • Thlaspi heterophyllum DC.

Description

Lepidium heterophyllum is similar in form to native Lepidium campestre and especially at the early seedling stage, both have been misidentified in Belgium.[3]

It is a perennial,[4] which can grow between 10–90 cm (3.9–35.4 in) tall.[5] The hirsute (or hairy) stems,[4] are often branched from the base,[5][4][6] It has grey-green foliage,[6] that has narrowly triangular,[5][6] variably toothed,[6] stem leaves which cling to the stem with long pointed auricles.[6][4] The stem leaves can grow up to 50 mm long.[6] The basal leaves are different, they have long stalks and are strap-shape,[6] or oblong-elliptic.[4] They can often have 1-3 pairs of small but broad sided lobes, they quickly fade at blooming time but can re-grow as the plant goes to seed.[6] It blooms between May and August,[5] or between May and September, in the UK,[6] and between May and July in the US.[4] The very small flowers (2–3.6 mm (0.079–0.142 in) long,[6]) are on short stalks at right angles to the stem, the plant can have several crowded, parallel-sided flower spikes.[6] The white spatulate (spoon-shaped) petals,[4] are as long as the oblong sepals.[5] and 6 styles, which have a notch.[6][4] The flower also has stamens with violet anthers.[5] After it has flowered, it produces a fruit capsule, which is oval and smooth, with a distinctive beak at the top.[5] They are (4.5–8.6 mm (0.18–0.34 in) long,[6] and inside are ovoid dark brown seeds.[4]

Phytochemistry

It was found after a phylogenetic analysis of the DNA of many species of 'Lepidium', that Lepidium heterophyllum, Lepidium hirtum, Lepidium campestre, and Lepidium perfoliatum formed a monophyletic group.[7]

It has been used in experiments growing in soils high in copper content, to determine if the plant could be used to help clean contaminated soils. [8]

Taxonomy

It was published and described by George Bentham in 'Cat. Pl. Pyrénées' on page 95 in 1826.[2][4][9]

It has one known subspecies; Lepidium heterophyllum subsp. rifanum (Emb. & Maire) J.M.Monts.[2]

The specific epithet heterophyllum, refers to the Greek for 'different leaves'.[10]

It has a few common names including 'Smith's cress' and 'Smith's pepperwort',[11] this is due to the plant once being named Lepidium smithii, by Sir William Hooker, in honour of the botanist, Sir James Edward Smith.[5] This name is now regarded as a synonym.[2] It is also known in the US, as 'purple antherfield pepperwort'[12][13][14] The pepperwort name came from plant looking like a 'pepperwort' (Lepidium campestre or other Lepidium species).[5]

Distribution and habitat
Plant seen in Sierra Madrona, Spain

Lepidium heterophyllum is native to temperate areas of western Europe.[11][9][15]

Range

It is found in Europe within Denmark, France, Germany, Ireland, the Netherlands, Portugal, Spain and the United Kingdom.[15]

It is also widely naturalised in other parts of Europe such as Belgium, the Czech Republic, Finland, Norway and Sweden. As well as Canada, Chile and the United States.[15] It has been recorded as found in British Columbia, Newfoundland and Labrador, California, Colorado, Maine, Massachusetts, New York (state), Oregon, Pennsylvania and Washington (state).[4] The records from Maine and Massachusetts are based on old plant collections, and it is not fully known if the plant has become established as part of the weedy flora of those states.[4] In Belgium, it was first recorded in fallow fields between 1881 and 1884 in Egenhoven, and then in 1886 near Bouillon. Later, it was observed in Stokt (in the province of Limburg, Netherlands), in the 19th century. Recently, in 2004 and 2005, it was recorded on gravelly riverbanks of River Maas (which rises in France and flowing through Belgium and the Netherlands to the North Sea).[16]

Habitat

It is found growing in acidic soils,[1][16] on hillsides,[4] in shingle, railway ballast and embankments, and, occasionally, in arable fields.[1][6][16]

It is normally found at altitudes of 0–425 m (0–1,394 ft) above sea level.[1][6][16]

Conservation

Populations of Lepidium heterophyllum currently are stable, but it seems to be decreasing in S.E. England.[16]

References
  1. Holubec, V.; Uzundzhalieva, K.; Vörösváry, G.; Donnini, D; Bulińska, Z.; Strajeru, S. (2011). "Lepidium heterophyllum". IUCN Red List of Threatened Species. 2011. Retrieved 26 November 2017.
  2. "Lepidium heterophyllum Benth. is an accepted name". 23 March 2012. theplantlist.org. Retrieved 26 November 2017.
  3. "Lepidium heterophyllum". alienplantsbelgium.be. 19 July 2012. Retrieved 26 November 2017.
  4. "FNA Vol. 7 Page 571, 578, 582, 583". efloras.org. Retrieved 26 November 2017.
  5. Reader's Digest Field Guide to the Wild Flowers of Britain. Reader's Digest. 1981. p. 51. ISBN 9780276002175.
  6. Simon Harrap Harrap's Wild Flowers (2013), p. 130, at Google Books
  7. Lee, Ji-Young; Mummenhoff, Klaus; Bowman, John L. (24 December 2002). "Allopolyploidization and evolution of species with reduced floral structures in Lepidium L. (Brassicaceae)". Proceedings of the National Academy of Sciences of the United States of America. 99 (26): 16835–16840. Bibcode:2002PNAS...9916835L. doi:10.1073/pnas.242415399. PMC 139230. PMID 12481035.
  8. Irena Twardowska, Herbert E. Allen and Max M. Häggblom (Editors) Soil and Water Pollution Monitoring, Protection and Remediation, p. 193, at Google Books
  9. "Brassicaceae Lepidium heterophyllum Benth". ipni.org. Retrieved 26 November 2017.
  10. "Myriophyllum heterophyllum Michx". swbiodiversity.org. Retrieved 27 November 2017.
  11. "Lepidium heterophyllum". rhs.org.uk. Retrieved 26 November 2017.
  12. Tim Johnson CRC Ethnobotany Desk Reference, p. 464, at Google Books
  13. "purpleanther field pepperweed". invasiveplantatlas.org. Retrieved 29 November 2017.
  14. Joseph M. DiTomaso and Evelyn A. Healy Weeds of California and Other Western States, Volume 1 (2007), p. 1786, at Google Books
  15. "Taxon: Lepidium heterophyllum Benth". npgsweb.ars-grin.gov. Retrieved 28 November 2017.
  16. "Lepidium heterophyllum". brc.ac.uk (Biological Records Centre). Retrieved 26 November 2017.

Other sources
  • Al-Shehbaz, I. A. 2010. A synopsis of the South American Lepidium (Brassicaceae) (Darwiniana) 48:141-167.
  • Botanical Society of the British Isles BSBI taxon database (on-line resource). (BSBI)
  • FNA Editorial Committee Flora of North America. 1993- (F NAmer)
  • Greuter, W. et al., eds. Med-Checklist. 1984- (L Medit)
  • Jalas, J. & J. Suominen Atlas florae europaeae. 1972- (Atlas Eur)
  • Tutin, T. G. et al., eds. Flora europaea. 1964-1980 (F Eur)
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