Roscoea purpurea (bhordaya)

Roscoea purpurea is a vigorously growing plant with flowers in a wide variety of colours, usually purple, but also pink, white and rarely bright red.

Roscoea purpurea
Roscoea purpurea (Image: Richard Wilford)

Species information

  • Scientific name: Roscoea purpurea Sm.
  • Common name(s): bhordaya (Nepali)
  • Synonym(s): Roscoea procera
  • Conservation status: Not Evaluated according to IUCN Red List criteria.
  • Habitat: Alpine grassland, steep, grassy hillsides, damp gullies and stony slopes; often on disturbed ground, growing out of old terrace walls or in the shade in forest margins.
  • Key uses: Ornamental, edible rhizomes, ethnoveterinary medicine.
  • Known hazards: None known.

Taxonomy

  • Class: Equisetopsida
  • Subclass: Magnoliidae
  • Superorder: Lilianae
  • Order: Zingiberales
  • Family: Zingiberaceae
  • Genus: Roscoea

About this species

Roscoea is a genus of 22 species belonging to the ginger family (Zingiberaceae), and occuring in the Himalaya. Roscoeas have fleshy roots that are dormant in winter. They are hardy in many regions but have delicate, orchid-like flowers that appear in mid-summer.

Roscoea purpurea was the first Roscoea species to be described around 1806 from specimens collected in Nepal by the Scotsman Francis Buchanan, who collected and described many new plants from India and Nepal. The genus is named after William Roscoe (1753–1831), who founded Liverpool’s first botanic garden in 1803 and had an interest in gingers.

Geography & Distribution

Native to the Himalaya from central India (Himachal Pradesh) to Nepal and the Bhutan–Assam frontier, between 1,500-3,100 m elevation.

Description

Roscoea purpurea has fleshy roots. The leaves (4–8) are soft and somewhat wavy, bright green, smooth or ciliate, 14–20 cm long and held horizontally or recurved. The leaf sheaths are often purple or reddish. The bracts are narrowly ovate and mostly hidden by the upper leaves.

The flowers are purple, mauve, red or white and appear in succession from among the upper leaves from June to September. Each flower only lasts one or two days. The floral tube is 6.5–10 cm long, but hidden by the bract and upper leaf sheath. The dorsal petal is ovate, whereas the lateral petals are shorter and rounded. The lip is three-lobed. The central lobe is obovate, 2 cm wide and divided at the tip, and the lateral lobes are linear-lanceolate. Stamen filaments have white, pointed appendages.

Illustration from Curtis's Botanical Magazine

Colour print of Roscoea purpurea after a watercolour by Christabel King

Colour print of Roscoea purpurea after a watercolour by Christabel King (1994), taken from Curtis's Botanical Magazine (Image: Christabel King)

Curtis’s Botanical Magazine (Editor: Martyn Rix) provides an international forum of particular interest to botanists and horticulturists, plant ecologists and those with a special interest in botanical illustration.

Now well over two hundred years old, the Magazine is the longest running botanical periodical featuring colour illustrations of plants. Each four-part volume contains 24 plant portraits reproduced from watercolour originals by leading international botanical artists. Detailed but accessible articles combine horticultural and botanical information, history, conservation and economic uses of the plants described.

Published for the Royal Botanic Gardens, Kew by Wiley-Blackwell Publishing.
See the Wiley-Blackwell Subscription Information page for rates (for both print and online).

Uses

Roscoea purpurea is cultivated as an ornamental. In northern India the fleshy roots are traditionally used for making a tonic to treat malaria. In Nepal they are boiled and eaten and also used in traditional veterinary medicine.

Cultivation

At Kew the Roscoea collection is repotted in late January to early February, in a moisture-retentive but well-drained compost, before the pots are plunged into sand in an outdoor frame. The pots are watered in, then only the sand is kept damp until the first signs of growth in spring. Once in full growth, they are kept well watered and shaded on hot days. Between the time the foliage dies back in autumn and repotting takes place in winter, both pots and plunge sand are kept completely dry.

Most species are propagated readily from offsets, but they are also easy to propagate from seed, although this does mean it takes longer before they reach flowering size.

This species at Kew

The first Kew collection of the striking red-flowered form was made by the Kew botanist William Baker on the Oxford University Ganesh Himal expedition in 1992, and this collection is still grown at Kew.

Roscoea purpurea can be seen growing in the Rock Garden. When the plants come into flower, pots are moved from the nursery into the Davies Alpine House for display. It can also be found at Wakehurst.

Alcohol-preserved specimens of Roscoea purpurea are held in Kew’s Herbarium, where they are available to researchers from around the world, by appointment. The details of some of these, including images, can be seen online in the Herbarium Catalogue.


References and credits

Cowley, J. (2007). The Genus Roscoea. Royal Botanic Gardens, Kew. (An earlier version is available as a pdf here).

Manandhar, N.P. (2002). Plants and People of Nepal. Timber Press, Portland, Oregon.

Sood Sudershna, S.K. (2008). Root Drug Plants of Ethnic India. Satish Serial Publishing House, New Delhi, India.

The Plant List (2010). Roscoea purpurea. http://www.theplantlist.org/tpl/record/kew-262605 (accessed 10 June 2011).

World Checklist of Selected Plant Families (2010). Roscoea purpurea. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet at:
http://apps.kew.org/wcsp/namedetail.do?name_id=262605 (accessed 10 June 2011)

Kew Science Editor: Martyn Rix
Kew contributors: Steve Davis (Sustainable Uses Group)
Copyediting: Malin Rivers

Although every effort has been taken to ensure that the information contained in these pages is reliable and complete, notes on hazards, edibility and suchlike included here are recorded information and do not constitute recommendations. No responsibility will be taken for readers’ own actions. Full website terms and conditions.




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