Lamium galeobdolon, commonly known as yellow archangel, golden dead-nettle, artillery plant, aluminium plant, or yellow weasel-snout,[3] is a widespread wildflower in Europe, and has been introduced elsewhere as a garden plant. It displays the zygomorphic flower morphology, opposite leaves, and square stems typical of the mint family, Lamiaceae. The flowers are soft yellow and borne in axial clusters, with a prominent 'hood' (the dorsal lobe of the corolla).

Yellow archangel
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Lamium
Species:
L. galeobdolon
Binomial name
Lamium galeobdolon
(L.) L.[1]
Synonyms[2]
Homotypic synonyms
    • Neckeria galeobdolon (L.) Forsyth f.
    • Galeobdolon galeobdolon (L.) H.Karst.
    • Galeopsis galeobdolon L.
    • Lamiastrum galeobdolon (L.) Ehrend. & Polatschek
    • Leonurus galeobdolon (L.) Scop.
    • Pollichia galeobdolon (L.) Schrank

Description edit

Lamium galeobdolon sensu lato is a large-leaved perennial plant growing from 15 to 60 cm (6 to 24 in) tall. The paired opposite leaves are stalked, broadly ovate with a cordate base and toothed margin. The underside of the leaves often appears purplish. The flowers grow in whorls in a terminal spike. The calyx is five-lobed. The corolla is yellow, 15 to 25 mm (0.6 to 1.0 in) long, the petals fused with a long tube and two lips. The upper lip is hooded and the lower lip has three similar-sized lobes with the central one being triangular and often streaked with orange. There are two short stamens and two long ones. The carpels are fused and the fruit is a four-chambered schizocarp.[4][5]

Identification edit

Subspecies of Lamium galeobdolon sensu lato are the only taxa in the genus with yellow flowers. All of the subspecies are stoloniferous except subsp. flavidum. The invasive subsp. argentatum is readily distinguished by its silvery white variegated leaves. Lamium galeobdolon subsp. galeobdolon and subsp. montanum can be difficult to distinguish unless the plant in question is in full flower. In that case, subsp. galeobdolon has a maximum of six (rarely seven) flowers per verticillaster while subsp. montanum averages ten flowers per verticillaster.[6]

Lamium galeobdolon subsp. flavidum is characterized by the lack of stolons, frequently branched fertile stems with upright flowering lateral shoots, and small flowers in many-flowered verticillasters.[7] An identification key for the remaining taxa follows:[8]

Identification Key
Lamium galeobdolon sensu lato in Central Europe
1a. Leaves and bracts (except for the uppermost) with a distinct silvery pattern (two flexuous bands along the midrib) persisting year around, bracts with wide apical teeth; flowers relatively large
Lamium galeobdolon subsp. argentatum
1b. Leaves generally without silvery pattern (if present, then never forming two continuous flexuous bands along the midrib); apical teeth of bracts mostly narrower; flowers relatively smaller
2
2a. The uppermost bracts ovate, generally less than twice as long as wide, with more-or-less equally distributed marginal teeth, apical tooth short and obtuse, lowermost bracts narrower or only slightly wider than the uppermost ones; the uppermost leaves shortly petiolate; verticillasters few-flowered (maximum number of flowers usually 4–7)
Lamium galeobdolon subsp. galeobdolon
2b. The uppermost bracts lanceolate, more than twice as long as wide, marginal teeth towards the apex more separated, apical tooth long and acute; lowermost bracts mostly distinctly wider than the uppermost ones; the uppermost leaves with longer petioles; maximum number of flowers in verticillasters generally 6–14
Lamium galeobdolon subsp. montanum

Note: Generally only fertile specimens allow a reliable determination.

Other taxa in the group can have marked leaves but those of subsp. argentatum are distinctive:[9]

Permanent silvery pattern on leaf lamina in L. argentatum always forms two flexuous bands along the midrib, mostly not interrupted by the lateral veins. They are distinctive particularly from the late autumn to the early spring when a contrast brownish-maroon colouring develops on the abaxial side and extends to the midrib-zone of the upper leaf side. Although variegated leaves were frequently observed in all other taxa in our study, they never matched the description above. Silvery-grey markings constituted merely separate splashes or flecks (small-sized in L. montanum and L. flavidum, larger in L. galeobdolon), not merged into continuous bands. Thus, a combination of two distinct silvery flexuous bands together with a strong chocolate-maroon zone along the midrib in winter can be regarded as specific L. argentatum markers.

In particular, a cultivar of subsp. flavidum known as 'Hermans Pride' has silver-spotted leaves unlike those of subsp. argentatum but the two taxa are sometimes confused.

The base chromosome number of taxa in genus Lamium is x = 9.[10] Lamium galeobdolon subsp. flavidum and subsp. galeobdolon are diploid (2n = 2x = 18) while subsp. argentatum and subsp. montanum are tetraploid (2n = 4x = 36). A few triploid individuals have been reported.[11] The triploids are thought to be natural hybrids between diploid subsp. galeobdolon and tetraploid subsp. argentatum.[12]

Taxonomy edit

Lamium galeobdolon was first described as Galeopsis galeobdolon by the Swedish botanist Carl Linnaeus in 1753.[13] Linnaeus himself placed Galeopsis galeobdolon in the genus Lamium in 1759, and therefore the correct name is Lamium galeobdolon (L.) L.[1][14]

Most authorities recognize four closely-related taxa, either as subspecies of Lamium galeobdolon,[2][15][16] or as full species in genus Lamium,[4] in which case the group of taxa is referred to as Lamium subgen. Galeobdolon.[17] Some authorities segregate the species into other genera (either Galeobdolon or Lamiastrum) but genus Lamium remains monophyletic in any case.[18]

Subpecies Species complexes
Lamium galeobdolon subsp. argentatum (Smejkal) J.Duvign. Lamium argentatum (Smejkal) Henker ex G.H.Loos Galeobdolon argentatum Smejkal Lamiastrum argentatum (Smejkal) Soják
Lamium galeobdolon subsp. flavidum (F.Herm.) Á.Löve & D.Löve Lamium flavidum F.Herm. Galeobdolon flavidum (F.Herm.) Holub Lamiastrum flavidum (F.Herm.) Ehrend.
Lamium galeobdolon subsp. galeobdolon Lamium galeobdolon (L.) L. sensu stricto Galeobdolon galeobdolon (L.) H.Karst. Lamiastrum galeobdolon (L.) Ehrend. & Polatschek
Lamium galeobdolon subsp. montanum (Pers.) Hayek
Basionym: Pollichia montana Pers.
Lamium montanum (Pers.) Hoffm. ex Kabath Galeobdolon montanum (Pers.) Rchb. Lamiastrum montanum (Pers.) Ehrend.

Lamium galeobdolon subsp. argentatum was first described as Galeobdolon argentatum by the Czech botanist Miroslav Smejkal in 1975.[19] In a comprehensive and influential treatment of genus Lamium published in 1989,[20] the Dutch botanist Jacob Mennema reduced the species to forma and placed it in synonymy with Lamium galeobdolon subsp. galeobdolon. Hence subsp. argentatum was neglected for a long time and its invasion history is poorly documented.[21] In Basel, Switzerland, Lamium galeobdolon subsp. argentatum tripled its occurrence in four decades while exhibiting "a higher growth rate and regeneration capacity" than the native subsp. galeobdolon.[22]

Most North American authorities recognize a single taxon, referred to as Lamium galeobdolon or Lamiastrum galeobdolon.[23][24][25] Following the taxonomy of Mennema, flora authors refer to either Lamium galeobdolon sensu lato or Lamium galeobdolon subsp. galeobdolon.[26][27][28] Lamium galeobdolon subsp. argentatum is not recognized in North America.

There are a number of closely related taxa that hybridize with L. galeobdolon and in some cases are not unequivocally accepted as distinct species but considered subspecies or varieties by many authors.[citation needed] Most well known among these is variegated yellow archangel (subsp. argentatum), whose leaves often have variegation, showing as silver patches arranged as a wide semicircle. This, and in particular its large-flowered and even stronger-marked cultivar 'Variegatum', is the taxon most often met with as a garden escapee.

Distribution edit

It is native to Europe, and found throughout Europe and Western Asia.[29]

An introduced species in the United States, Washington state has declared it a "noxious weed" and banned its sale.[30]

Ecology edit

Based on morphological characters, number of chromosomes, pattern of geographical distribution, and phytochemistry, early botanists hypothesized that the tetraploid subsp. montanum originated as a hybrid between the two diploid taxa, subsp. flavidum and subsp. galeobdolon.[31] However, more recent phylogenetic data suggests that subsp. montanum originated from subsp. flavidum alone. Similarly, there is conflicting evidence regarding the origins of the tetraploid subsp. argentatum suggesting that it may or may not have originated from subsp. galeobdolon alone.[32]

Lamium galeobdolon subsp. argentatum spreads easily and so has been commonly used as an ornamental ground cover. It can be invasive in places where it is not native and caution must be taken when planting it in these areas.[33]

Gallery edit

References edit

  1. ^ a b "Lamium galeobdolon (L.) L.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 13 March 2024.
  2. ^ a b "Lamium galeobdolon (L.) L.". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 13 March 2024.
  3. ^ Lees, Edwin (1852). The Botany of Malvern Hills, in the counties of Worcester, Hereford, and Gloucester. London: David Bogue. p. 61.
  4. ^ a b Meyer, Thomas. "Taubnesselarten mit gelber Krone" [Deadnettle species with yellow crown]. Flora-de: Flora of Germany (in German). Retrieved 16 March 2024.
  5. ^ "Yellow archangel: Lamiastrum galeobdolon". NatureGate. Retrieved 28 March 2024.
  6. ^ Rosenbaumová, Plačková & Suda (2004), p. 234.
  7. ^ Rosenbaumová, Plačková & Suda (2004), p. 220.
  8. ^ Rosenbaumová, Plačková & Suda (2004), pp. 236–237.
  9. ^ Rosenbaumová, Plačková & Suda (2004), p. 235.
  10. ^ Mennema (1989), pp. 12–13.
  11. ^ Rosenbaumová, Plačková & Suda (2004), pp. 220, 223–225.
  12. ^ Rosenbaumová, Plačková & Suda (2004), pp. 231–233.
  13. ^ "Galeopsis galeobdolon L.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 13 March 2024.
  14. ^ Mennema (1989), p. 41.
  15. ^ "Lamium galeobdolon (L.) L.". WFO Plant List. Retrieved 18 March 2024.
  16. ^ "Lamium galeobdolon". Euro+Med Plantbase. Retrieved 18 March 2024.
  17. ^ Rosenbaumová, Plačková & Suda (2004).
  18. ^ Bendiksby et al. (2011), p. 995.
  19. ^ "Galeobdolon argentatum Smejkal". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 23 March 2024.
  20. ^ Mennema (1989).
  21. ^ "Lamium galeobdolon". Manual of the Alien Plants of Belgium. Retrieved 20 March 2024.
  22. ^ Rusterholz, Huber & Baur (2023).
  23. ^ Weakley, Alan S.; Southeastern Flora Team (2024). "Lamium galeobdolon (Linnaeus) Linnaeus". Flora of the southeastern United States. University of North Carolina Herbarium, North Carolina Botanical Garden. Retrieved 16 March 2024.
  24. ^ "Lamium galeobdolon (Linnaeus) Linnaeus". Canadensys. Retrieved 16 March 2024.
  25. ^ "Lamiastrum galeobdolon". NatureServe Explorer. NatureServe. Retrieved 18 March 2024.
  26. ^ Gilman (2015), p. 468.
  27. ^ Haines (2011), p. 639.
  28. ^ "Lamium galeobdolon — yellow henbit". Go Botany. Native Plant Trust. Retrieved 23 March 2024.
  29. ^ "Lamium galeobdolon - yellow archangel". Royal Horticultural Society.
  30. ^ "Yellow archangel". www.kingcounty.gov. King County, Washington local administration.
  31. ^ Mennema (1989), pp. 13–14.
  32. ^ Bendiksby et al. (2011), p. 996.
  33. ^ "Aluminium Plant". Biosecurity New Zealand. Archived from the original on 2017-02-27. Retrieved 27 March 2024.

Bibliography edit

External links edit