Lamium purpureum

Lamium purpureum, known as red dead-nettle,[1] purple dead-nettle, or purple archangel,[2] is a herbaceous flowering plant native to Europe and Asia.

Red dead-nettle
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Lamium
Species:
L. purpureum
Binomial name
Lamium purpureum

Description

Lamium purpureum grows with square stems to 5–20 cm [3](rarely 30 cm) in height. The leaves have fine hairs, are green at the bottom and shade to purplish at the top; they are 2–4 cm long and broad, with a 1–2 cm petiole (leaf stalk), and wavy to serrated margins.

The zygomorphic flowers are bright red-purple, with a top hood-like petal, two lower lip petal lobes and minute fang-like lobes between. The corolla shows a line of hairs near the base of the tube.[3] They may be produced throughout the year, including mild weather in winter. This allows bees to gather its nectar for food when few other nectar sources are available. It is also a prominent source of pollen for bees in March/April (in UK), when bees need the pollen as protein to build up their nest.

It is often found alongside Henbit Dead-nettle (Lamium amplexicaule), which is easily mistaken for it since they both have similar looking leaves and similar bright purple flowers; they can be distinguished by the stalked leaves of Red Dead-nettle on the flower stem, compared to the unstalked leaves of Henbit Dead-nettle.[3]

Though superficially similar to species of Urtica (true nettles) in appearance, it is not related and does not sting, hence the name "dead-nettle".

Uses

Young plants have edible tops and leaves, used in salads or in stir-fry as a spring vegetable. If finely chopped it can also be used in sauces.

Undyed, the pollen itself is a red colour and is very noticeable on the heads of bees that frequent its flowers.

Habitat

Frequent in meadows, forest edges, roadsides and gardens.[3]

Distribution

Lamium purpureum is a common weed in the western United States [4]Canada, Ireland, and the British Isles.[5]

Biochemistry

The essential oil is characterized by its high contents of germacrene D.[6] The seed oil contains 16% of an acid characterized as (−)-octadeca-5,6-trans-16-trienoic acid (trivial name `lamenallenic acid'). Other unsaturated esters identified by their cleavage products are oleate, linoleate and linolenate.[7]

The plant contains phenylethanoid glycosides named lamiusides A, B, C, D and E.[8] It possesses a flavonol 3-O-glucoside-6″-O-malonyltransferase.[9]

Pictures

References
  1. "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2014-10-23. Retrieved 2014-10-17.
  2. Martin, W. Keble, 1965. The Concise British Flora in Colour. George Rainbird Limited.
  3. Parnell, J. and Curtis, T. 2012. Webb's An Irish Flora. Cork University Press. ISBN 978-185918-4783
  4. Whitson, Tom (2000). Weeds of the West. Newark, CA: Western Society of Weed Science in cooperation with the Western United States Land Grant Universities Cooperative Extension Services. ISBN 9780788149269.
  5. Clapham, A.R., Tutin, T.G. and Warburg, E.F. 1968. Excursion Flora of the British Isles. Cambridge University Press. ISBN 0-521-04656-4
  6. Flamini, G.; Cioni, P. L.; Morelli, I. (2005). "Composition of the essential oils and in vivo emission of volatiles of four Lamium species from Italy: L. Purpureum, L. Hybridum, L. Bifidum and L. Amplexicaule". Food Chemistry. 91: 63–68. doi:10.1016/j.foodchem.2004.05.047.
  7. Mikolajczak, KL; Rogers, MF; Smith Cr, Jun; Wolff, IA (1967). "An octadecatrienoic acid from Lamium purpureum L. Seed oil containing 5,6-allenic and trans-16-olefinic unsaturation". Biochemical Journal. 105 (3): 1245–1249. doi:10.1042/bj1051245. PMC 1198447. PMID 16742552.
  8. Ito, N.; Nihei, T.; Kakuda, R.; Yaoita, Y.; Kikuchi, M. (2006). "Five new phenylethanoid glycosides from the whole plants of Lamium purpureum L". Chemical & Pharmaceutical Bulletin. 54 (12): 1705–1708. doi:10.1248/cpb.54.1705. PMID 17139106.
  9. Suzuki, H. (2004). "CDNA cloning and functional characterization of flavonol 3-O-glucoside-6"-O-malonyltransferases from flowers of Verbena hybrida and Lamium purpureum". Journal of Molecular Catalysis B: Enzymatic. 28 (2–3): 87–93. doi:10.1016/j.molcatb.2004.01.005.
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