Roscoea cangshanensis
Encyclopedia
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.
which has been found only in one location, in the Cang Shan mountains in Yunnan
, China
, where it occurs at 2,600 metres in damp soil under pines.
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. Plants of R. cangshanensis are usually 22–30 cm tall, with three or sometimes four leaves. The hairless (glabrous) leaf blade is usually 7–24 cm long by 1.5–2.5 cm wide, but may be as short as 2 cm. It narrows at the base, becoming almost like a stalk (petiole
). There is a small ligule
, about 1.5 mm long, at the junction of the blade and sheath.
In its native habitats, R. cangshanensis flowers between July and August. The stem (peduncle
) of the flower spike is hidden by the leaf sheaths. The yellowish-green bracts which subtend the flowers are very short, only 5–15 mm long. Each spike has two or three flowers, which are reddish purple to pale purple.
Each flower has the typical structure for Roscoea
(see the diagrams in that article). There is a tube-shaped outer calyx, 5.5–7 cm long with a two-toothed apex, which is pale green to white. Next the three petal
s (the corolla) form a long tube, 10–12.5 cm in length, terminating in three lobes, a narrow upright central lobe, 1.5–2.5 cm long by 8–12 mm wide, and two somewhat narrower side lobes, 1.5–2.5 cm long by 3–4 mm wide. Inside the petals are structures formed from four sterile stamen
s (staminodes): two lateral staminodes form what appear to be small upright petals, about 1.2 cm long by 7 mm wide; two central staminodes are fused at the base to form a lip or labellum, 2.5–3.5 cm long by 2.5–3 cm wide. The labellum bends backwards and is deeply split into two lobes, each divided again. The base of the labellum is marked with narrow white lines.
The single functional stamen has a white anther, about 6 mm long, with approximately 3 mm long spurs formed from the connective tissue between the two capsules of the anther. The ovary is about 1.2 cm long.
.
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, 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. cangshanensis was not described until after the phylogenetic analysis by Ngamriabsakul et al. It occurs in the geographical region of the Chinese clade, and appears to be related to both R. forrestii
and R. debilis.
Herbaceous plant
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
native to the mountains of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, being found in Yunnan
Yunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
. Most members of the ginger family (Zingiberaceae
Zingiberaceae
Zingiberaceae, or the Ginger family, is a family of flowering plants consisting of aromatic perennial herbs with creeping horizontal or tuberous rhizomes, comprising ca. 52 genera and more than 1300 species, distributed throughout tropical Africa, Asia, and the Americas.Many species are important...
), to which it belongs, are tropical, but R. canshanensis, like other species of Roscoea
Roscoea
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...
, grows in much colder mountainous regions.
Description
Roscoea cangshanensis is a perennial herbaceous plantHerbaceous plant
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
which has been found only in one location, in the Cang Shan mountains in Yunnan
Yunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, where it occurs at 2,600 metres in damp soil under pines.
Like all members of the genus Roscoea, it dies back each year to a short vertical rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
, to which are attached the tuberous roots
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...
. When growth begins again, "pseudostems" are produced: structures which resemble stems but are actually formed from the tightly wrapped bases (sheaths) of its leaves. Plants of R. cangshanensis are usually 22–30 cm tall, with three or sometimes four leaves. The hairless (glabrous) leaf blade is usually 7–24 cm long by 1.5–2.5 cm wide, but may be as short as 2 cm. It narrows at the base, becoming almost like a stalk (petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
). There is a small ligule
Ligule
A ligule — is a thin outgrowth at the junction of leaf and leafstalk of many grasses and sedges or a strap-shaped corolla, such as that of a ray floret in plants in the daisy family....
, about 1.5 mm long, at the junction of the blade and sheath.
In its native habitats, R. cangshanensis flowers between July and August. The stem (peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
) of the flower spike is hidden by the leaf sheaths. The yellowish-green bracts which subtend the flowers are very short, only 5–15 mm long. Each spike has two or three flowers, which are reddish purple to pale purple.
Each flower has the typical structure for Roscoea
Roscoea
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...
(see the diagrams in that article). There is a tube-shaped outer calyx, 5.5–7 cm long with a two-toothed apex, which is pale green to white. Next the three petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s (the corolla) form a long tube, 10–12.5 cm in length, terminating in three lobes, a narrow upright central lobe, 1.5–2.5 cm long by 8–12 mm wide, and two somewhat narrower side lobes, 1.5–2.5 cm long by 3–4 mm wide. Inside the petals are structures formed from four sterile stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s (staminodes): two lateral staminodes form what appear to be small upright petals, about 1.2 cm long by 7 mm wide; two central staminodes are fused at the base to form a lip or labellum, 2.5–3.5 cm long by 2.5–3 cm wide. The labellum bends backwards and is deeply split into two lobes, each divided again. The base of the labellum is marked with narrow white lines.
The single functional stamen has a white anther, about 6 mm long, with approximately 3 mm long spurs formed from the connective tissue between the two capsules of the anther. The ovary is about 1.2 cm long.
Taxonomy
Roscoea cangshanensis was first described scientifically in 2007 in a paper by four Chinese scientists, of whom three are given as the authors of the binomial name: Luo Ming-Hua, Gao Xin-Fen and Lin Hong-Hui. The specific epithet refers to the Cang Shan (苍山) mountain range where it was found.Evolution and phylogeny
The Zingiberaceae family 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 platesPlate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
.
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, being divided by the Brahmaputra River
Brahmaputra River
The Brahmaputra , also called Tsangpo-Brahmaputra, is a trans-boundary river and one of the major rivers of Asia. It is the only Indian river that is attributed the masculine gender and thus referred to as a in Indo-Aryan languages and languages with Indo-Aryan influence...
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. cangshanensis was not described until after the phylogenetic analysis by Ngamriabsakul et al. It occurs in the geographical region of the Chinese clade, and appears to be related to both R. forrestii
Roscoea forrestii
Roscoea forrestii is a perennial herbaceous plant occurring in the Sichuan and Yunnan provinces of China. Most members of the ginger family , to which it belongs, are tropical, but R. forrestii, like other species of Roscoea, grows in much colder mountainous regions...
and R. debilis.