Roscoea alpina

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Roscoea alpina
Roscoea alpina 120819 cropped.jpg
In cultivation
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Zingiberales
Family: Zingiberaceae
Genus: Roscoea
Species:
R. alpina
Binomial name
Roscoea alpina
Royle [1]
Roscoea alpina in Nepal (labellum appears to be trilobed) Whf purple 45 lightened.jpg
Roscoea alpina in Nepal (labellum appears to be trilobed)

Roscoea alpina is a perennial herbaceous plant native to the Himalayas. [1] Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. alpina, like other species of Roscoea , grows in much colder mountainous regions. [2] It is sometimes grown as an ornamental plant in gardens. [3]

Contents

Description

Roscoea alpina is a perennial herbaceous plant. Like all members of the genus Roscoea, it dies back each year to a short vertical rhizome, to which are attached the tuberous roots. When growth begins again, "pseudostems" are produced: structures which resemble stems but are actually formed from the tightly wrapped bases (sheaths) of its leaves. [4] R. alpina is one of the smaller members of the genus; plants are 10–20 cm tall, with four to six leaves. The first two or three leaves consist only of a sheath; the remaining two or three have in addition a smooth (glabrous) leaf blade, free from the pseudostem, 3–12 cm long by 1.2–2 cm wide. There is a very small ligule, extending to about 0.5 mm, at the junction of the leaf sheath and blade. The leaf blades taper to a point. [2]

In its native habitats, R. alpina flowers between May and August. The stem (peduncle) of the flower spike is hidden by the leaf sheaths. At the base of the flower spike there is a small bract, 3–10 mm long. Flowers open in succession and are purple or lilac in colour. [2]

Each flower has the typical structure for Roscoea (see the diagrams in that article). There is a tube-shaped outer calyx, 4–5 cm long with a two-lobed apex. Next the three petals (the corolla) form a tube which is longer than the calyx and terminates in three lobes, an upright more-or-less circular central lobe, about 1.5 cm in diameter (which forms a hood over the rest of the flower [3] ), and two more elongated side lobes. Inside the petals are structures formed from four sterile stamens (staminodes): two lateral staminodes form what appear to be upright petals, smaller than the corolla lobes; two central staminodes are fused to form a lip or labellum, about 1.5 cm long, which is divided at the end into two lobes. [2] [4]

The single functional stamen has a white or cream anther, about 5–6 mm long, with 1.5–2 mm long spurs formed from the connective tissue between the two capsules of the anther. The ovary expands to a 2.5–3.5 cm long capsule when seed is set. [2]

Taxonomy

Roscoea alpina was first described scientifically in 1839 by John Forbes Royle, [1] a British botanist who was born in India and worked for the East India Company. [5] The specific epithet refers to the alpine habitat of the species. [6]

For a long time R. scillifolia was incorrectly known in horticulture as R. alpina; Cowley (2007) cites articles written in 1938, the 1960s and 1970, all of which use this name for what is actually R. scillifolia. [7]

Evolution and phylogeny

The family Zingiberaceae is mainly tropical in distribution. The unusual mountainous distribution of Roscoea may have evolved relatively recently and be a response to the uplift taking place in the region in the last 50 million years or so due to the collision of the Indian and Asian tectonic plates. [8]

Species of Roscoea divide into two clear groups, a Himalayan clade and a "Chinese" clade (which includes some species from outside China). The two clades correspond to a geographical separation, their main distributions being divided by the Brahmaputra River as it flows south at the end of the Himalayan mountain chain. It has been suggested that the genus may have originated in this area and then spread westwards along the Himalayas and eastwards into the mountains of China and its southern neighbours. R. alpina falls into the Himalayan clade as would be expected from its distribution. It appears to be closely related to R. auriculata . [8]

Distribution and habitat

Roscoea alpina is found all along the Himalayas, in Kashmir, Tibet, India, Nepal, Sikkim and Bhutan (the Flora of China includes Burma [2] ). [1] In Tibet it grows in coniferous forests between 3,000 and 3,600 metres. [2]

Cultivation

Some Roscoea species and cultivars, including R. alpina, are grown in rock gardens. They generally require a relatively sunny position with moisture-retaining but well-drained soil. As they do not appear above ground until late spring or even early summer, they escape frost damage in regions where subzero temperatures occur. When grown at Royal Botanic Gardens, Kew, R. alpina requires more shade than other species of Roscoea. It flowers in late spring to early summer, the leaves elongating afterwards. White forms are known. [3]

The height reached in cultivation, up to 40 cm, [3] exceeds that given for the species in the wild, where it is said to reach only 20 cm. [2]

For propagation, see Roscoea: Cultivation.

Related Research Articles

<i>Roscoea</i> Genus of flowering plants

Roscoea is a genus of perennial plants of the family Zingiberaceae. Most members of the family are tropical, whereas Roscoea species are native to mountainous regions of the Himalayas, China and its southern neighbours. Roscoea flowers superficially resemble orchids, although they are not related. The flowers of Roscoea have a complicated structure, in which some of the showy coloured parts are not formed by petals, but by staminodes, sterile stamens which have evolved to become like petals. Some species are grown as ornamental plants in gardens.

<i>Roscoea auriculata</i> Species of plant

Roscoea auriculata is a perennial herbaceous plant occurring in the eastern Himalayas, in Tibet, Bhutan, Nepal and Sikkim. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. auriculata, like other species of Roscoea, grows in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens.

<i>Roscoea cautleyoides</i> Species of flowering plant

Roscoea cautleyoides is a perennial herbaceous plant occurring in the Sichuan and Yunnan provinces of China. The scientific name is also spelt Roscoea cautleoides. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. cautleyoides, like other species of Roscoea, grows in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens.

<i>Roscoea humeana</i> Species of plant

Roscoea humeana is a species of flowering plant in the Zingiberaceae family. It is a perennial occurring in the Sichuan and Yunnan provinces of China. Most members of the ginger family, to which it belongs, are tropical, but R. humeana, like other species of Roscoea, grows in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens.

<i>Roscoea purpurea</i> Species of flowering plant

Roscoea purpurea is a perennial herbaceous plant occurring in the Himalayas, particularly Nepal. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but species of Roscoea grow in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens.

<i>Roscoea tibetica</i> Species of flowering plant

Roscoea tibetica is a perennial herbaceous plant native to the mountains of China, being found in Tibet, Sichuan and Yunnan. The species formerly included plants found in Bhutan; in 2000, these were separated into a new species, Roscoea bhutanica. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. tibetica, like other species of Roscoea, grows in much colder mountainous regions. R. tibetica is sometimes grown as an ornamental plant in gardens. In 2020, it was proposed that R. tibetica be split again.

<i>Roscoea kunmingensis</i> Species of flowering plant

Roscoea kunmingensis is a perennial herbaceous plant native to the mountains of China, being found in Yunnan. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. kunmingensis, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea capitata</i> Species of flowering plant

Roscoea capitata is a perennial herbaceous plant native to the Himalayas, being found in Nepal. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. capitata, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea forrestii</i> Species of flowering plant

Roscoea forrestii is a perennial herbaceous plant occurring in the Sichuan and Yunnan provinces of China. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. forrestii, like other species of Roscoea, grows in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens. It was named after George Forrest (1873–1932) who discovered it in Yunnan.

<i>Roscoea tumjensis</i> Species of flowering plant

Roscoea tumjensis is a perennial herbaceous plant occurring in the Himalayas, in Nepal. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. tumjensis, like other species of Roscoea, grows in much colder mountainous regions.

Roscoea cangshanensis is a perennial herbaceous plant native to the mountains of China, being found in Yunnan. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. canshanensis, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea praecox</i> Species of flowering plant

Roscoea praecox is a perennial herbaceous plant occurring in the Yunnan province of China. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. praecox, like other species of Roscoea, grows in much colder mountainous regions. It is sometimes grown as an ornamental plant in gardens.

<i>Roscoea bhutanica</i> Species of flowering plant

Roscoea bhutanica is a perennial herbaceous plant native to the mountains of Bhutan and Tibet. Formerly regarded as part of Roscoea tibetica, it was recognized as a separate species in 2000. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. bhutanica, like other species of Roscoea, grows in much colder mountainous regions.

Roscoea brandisii is a species of herbaceous flowering plant in the Zingiberaceae family. It is a perennial found in the state of Meghalaya, India. Most members of the ginger family, to which it belongs, are tropical, but R. brandisii, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea nepalensis</i> Species of flowering plant

Roscoea nepalensis is a perennial herbaceous plant found in Nepal. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. nepalensis, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea debilis</i> Species of flowering plant

Roscoea debilis is a perennial herbaceous plant found in Yunnan, China. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. debilis, like other species of Roscoea, grows in much colder mountainous regions.

<i>Roscoea schneideriana</i> Species of flowering plant

Roscoea schneideriana is a perennial herbaceous plant found in China, in Tibet, Sichuan and Yunnan. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but R. schneideriana, like other species of Roscoea, grows in much colder mountainous regions.

Roscoea ganeshensis is a perennial herbaceous plant occurring in Ganesh Himal in central Nepal. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but like other species of Roscoea, R. ganeshensis grows in much colder mountainous regions. It is used as an ornamental garden plant, requiring moisture and shade in the summer.

<i>Roscoea wardii</i> Species of flowering plant

Roscoea wardii is a perennial herbaceous plant occurring from eastern Arunachal Pradesh in India to western Yunnan in China. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but like other species of Roscoea, R. wardii grows in much colder mountainous regions.

<i>Roscoea scillifolia</i> Species of flowering plant

Roscoea scillifolia is a perennial herbaceous plant occurring in Yunnan in China. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but like other species of Roscoea, R. scillifolia grows in much colder mountainous regions. As of 2013, the species is only known in cultivation and may be extinct in the wild.

References

  1. 1 2 3 4 "Roscoea alpina", World Checklist of Selected Plant Families , Royal Botanic Gardens, Kew, 2011, retrieved 2011-10-03
  2. 1 2 3 4 5 6 7 8 Wu, Delin & Larsen, Kai (2000), "Roscoea alpina", in Wu, Zhengyi; Raven, Peter H. & Hong, Deyuan (eds.), Flora of China Vol. 24, Beijing; St. Louis: Science Press; Missouri Botanical Garden, retrieved 2011-10-01
  3. 1 2 3 4 Wilford, Richard (1999), "Roscoeas for the rock garden", Quarterly Bulletin of the Alpine Garden Society, 67 (1): 93–101
  4. 1 2 Wu, Delin & Larsen, Kai (2000), "Roscoea", in Wu, Zhengyi; Raven, Peter H. & Hong, Deyuan (eds.), Flora of China Vol. 24, Beijing; St. Louis: Science Press; Missouri Botanical Garden, retrieved 2011-10-01
  5. ↑ Chisholm, Hugh, ed. (1911). "Royle, John Forbes"  . Encyclopædia Britannica . 23 (11th ed.). Cambridge University Press. pp. 794–795.
  6. ↑ Hyam, R. & Pankhurst, R.J. (1995), Plants and their names : a concise dictionary, Oxford: Oxford University Press, ISBN   978-0-19-866189-4
  7. ↑ Cowley 2007, pp. 102–103.
  8. 1 2 Ngamriabsakul, C.; Newman, M.F. & Cronk, Q.C.B. (2000), "Phylogeny and disjunction in Roscoea (Zingiberaceae)" (PDF), Edinburgh Journal of Botany, 57 (1): 39–61, doi:10.1017/s0960428600000032 , retrieved 2011-10-03

Bibliography

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