Cytisus scoparius

Cytisus scoparius
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fabales
Family:	Fabaceae
Genus:	Cytisus
Species:	C. scoparius
Binomial name
Cytisus scoparius (L.) Link
Synonyms
Spartium scoparium L. Genista scoparius (L.) Lam. Sarothamnus scoparius (L.) K.Koch Sarothamnus bourgaei Boiss. Sarothamnus oxyphyllus Boiss. Sarothamnus bourgaei (Boiss) Sarothamnus oxyphyllus(Boiss)

Cytisus scoparius, the Common Broom and Scotch Broom, syn. Sarothamnus scoparius, is a perennial leguminous shrub native to western and central Europe,.^[1]

In Britain and Ireland the standard name is Broom,^[2][3][4] but this name is also used generically for other related species (see broom), and the term Common Broom is sometimes used for clarification.^[5][6] In other English-speaking countries, the most prevalent common name is Scotch Broom^[7] (or Scot's Broom); English Broom is also occasionally used.

Classification

There are two subspecies of Cytisus scoparius:^[1][2]

• Cytisus scoparius subsp. scoparius. Throughout the species' range.
• Cytisus scoparius subsp. maritimus (Rouy) Heywood. Western Europe, on maritime cliffs. Differs in prostrate growth, not over 0.4 m tall, and downy young shoots.

Description

Illustration of Cytisus scoparius from Köhler's Medicinal Plants (1887)

Plants of Cytisus scoparius typically grow to 1–3 m (3–9 ft) tall, rarely to 4 m (13 ft), with main stems up to 5 cm (2 in)thick, rarely 10 cm (4 in). The shrubs have green shoots with small deciduous trifoliate leaves 5–15 mm long, and in spring and summer is covered in profuse golden yellow flowers 20–30 mm from top to bottom and 15–20 mm wide. Flowering occurs after 50-80 growing degree days. In late summer, its legumes (seed pods) mature black, 2–3 cm long, 8 mm broad and 2–3 mm thick; they burst open, often with an audible crack, forcibly throwing seed from the parent plant. This is the hardiest species of broom, tolerating temperatures down to about -25°C, +10°F.^{[clarification needed][2][4][8]} Cytisus scoparius contains toxic alkaloids that depress the heart and nervous system.^[9]

Distribution and habitat

Cytisus scoparius is found in sunny sites, usually on dry, sandy soils at low altitudes.^[2] In some places outside of its native range, such as India, South America and western North America, it has become an ecologically destructive colonizing invasive species in grassland, shrub and woodland, and other habitats .^[10][11]

As a legume, these shrubs fixes nitrogen in the soil by a symbiotic relationship with Rhizobium bacteria.

Cultivation

Cytisus scoparius is widely cultivated as an ornamental plant, with several cultivars selected for variation in flower colour, including "Moonlight" with deep yellow flowers, "Andreanus" and "Firefly" with dark orange-red flowers, and growth habit, including "Pendula" with pendulous branchlets.^[8]

Invasive species

Broom as an invasive species in the United States.

Cytisus scoparius has been introduced into several other continents outside its native range and is classified as a noxious invasive species in California and the Pacific Northwest^{[clarification needed]} in North America,^[10] and in Australia,^{[citation needed]} New Zealand^{[citation needed]} and India.^{[citation needed]} These shrubs commonly grow in disturbed areas and along utility and transportation right-of-ways. The prolific growth of this species after timber harvest inhibits reforestation by competing with seedling trees.^[12]

It is estimated that it is responsible for US$47 million in lost timber production each year in Oregon.^[13] In New Zealand broom the species estimated to cost the forestry industry NZ$90 million and farmers NZ$10 million.^[14] Biological control for broom has been investigated since the mid 1980s with a number of species being trialled. They include the broom twig miner (Leucoptera spartifoliella), the broom seed beetles (Bruchidius villosus) the broom gall mite (Aceria genistae) the sap-sucking broom psyllid (Arytainilla spartiophila) and recently the broom leaf beetle (Gonioctena olivacea) and the broom shoot moth (Agonopterix assimilella).^[15]

Some attempts have been made to develop biological controls in affected areas, using three broom-feeding insects, the psyllid Arytainilla spartiophylla, the beetle Bruchidius villosus, and the moth Leucoptera spartifoliella.^[16]

Phytochemicals

The plant yields amines (tyramine, dopamine), flavonoids (genistoside, spiracoside and scoparoside) and alkaloids (sparteine, in the twigs, lupanine, in seeds, ammodendrine or hydroxylupanine).

Although it has poisonous flowers, the plant can be used for smoking.

Royal symbols

The name of the House of Plantagenet, rulers of England in the Middle Ages, was derived from common broom, which was then known as "planta genista" in Latin. The "broomscod", or seed-pod, was the personal emblem of Charles VI of France.

Images

• 

  Close-up of flowers

• 

  Broom in Wellington, New Zealand, where it is an invasive species.

References

1. ^ ^{a b} Flora Europaea: Cytisus scoparius
2. ^ ^{a b c d} Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. Hodder & Stoughton. ISBN 0-340-40170-2.
3. ^ Botanical Society of the British Isles (zip file)
4. ^ ^{a b} Vedel, H. & Lange, J. (1960). Trees and bushes. Metheun, London.
5. ^ Wild Flowers of the Loch Lomond and Trossachs National Park, Scotland
6. ^ Garden World: common broom
7. ^ National Park Service: Scotch Broom
8. ^ ^{a b} Bean, W. J. (1970). Trees and Shrubs Hardy in the British Isles. John Murray, London. ISBN 0-7195-1790-7
9. ^ Pojar, Jim, A. MacKinnon, and Paul B. Alaback. Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia & Alaska. Redmond, WA: Lone Pine Pub., 1994.
10. ^ ^{a b} http://www.invasivespeciesinfo.gov/plants/scotchbroom.shtml USDA
11. ^ Journal of the Bombay Natural History Society, 103 (2-3), May-Dec 2006 356-365 Habitat Modifications By Scotch Broom Cytisus Scoparius Invasion Of Grasslands Of The Upper Nilgiris In India, Ashfaq Ahmed Zarri1, 2, Asad R. Rahmani1,4 And Mark J. Behan3 1 Bombay Natural History Society, Hornbill House, S.B. Singh Road Mumbai 400 023, Maharashtra, India. 2 Present Address: Centre for Biodiversity Studies, Baba Ghulam Shah Badshah University, Rajouri 185131, J&K, India. Email: [e-mail] 3 Division of Biological Sciences, University of Montana, Missoula 59812, USA. 4 Email: [e-mail]
12. ^ "Invasive Plant Species Management Plan". McDonald-Dunn Forest Plan, Appendix 7. Oregon State University, College of Forestry. http://www.cof.orst.edu/cof/admin/execom/FEC11-7-06%20Appendix%207.pdf. Retrieved 2006-12-20. ^{[dead link]}
13. ^ "Scotch broom". ODA Plant Division, Noxious Weed Control. http://www.oregon.gov/ODA/PLANT/WEEDS/profile_scotchbroom.shtml. Retrieved 2006-09-03. 
14. ^ Press release (2008-02-12). "New bio-controls for pest plant". Landcare Research. http://www.landcareresearch.co.nz/news/release.asp?Ne_ID=263. Retrieved 2008-03-02. 
15. ^ "What's New In Biological Control of Weeds?" (pdf). Landcare Research. November 2006. http://www.landcareresearch.co.nz/publications/newsletters/weeds/wtsnew38.pdf. Retrieved 2008-03-02. 
16. ^ CSIRO: Biological control

External links

• Bioimages - numerous photos
• Growing native plants
• Species Profile- Scotch Broom (Cytisus scoparius (L.), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Scotch Broom.
• Garry Oak ecosystems: Invasive species