''Roscoea cangshanensis'' is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

native to the mountains of

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, being found in

Yunnan Yunnan , () is a landlocked Provinces of China, province in Southwest China, the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is ...

. Most members of the ginger family (

Zingiberaceae Zingiberaceae () or the ginger family is a family of flowering plants made up of about 50 genera with a total of about 1600 known species of aromatic perennial herbs with creeping horizontal or tuberous rhizomes distributed throughout tropical Af ...

), to which it belongs, are tropical, but ''R. canshanensis'', like other species of ''

Roscoea ''Roscoea'' is a genus of perennial plants of the family (biology), family Zingiberaceae (the ginger family). Most members of the family are tropical, whereas ''Roscoea'' species are native to mountainous regions of the Himalayas, China and its ...

'', grows in much colder mountainous regions.

Description

''Roscoea cangshanensis'' is a

. Like all members of the genus ''Roscoea'', it dies back each year to a short vertical

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

, to which are attached the tuberous roots. When growth begins again, "

pseudostem A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrien ...

s" 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 A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ...

, 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 ''

'' (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 Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

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 The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s (

staminodes In botany, a staminode is an often rudimentary, sterile or abortive stamen, which means that it does not produce pollen.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''; Published by Gerald Duckworth & C ...

): 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 The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

, 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 In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

: Luo Ming-Hua, Gao Xin-Fen and Lin Hong-Hui. The specific epithet refers to the Cangshan mountain range where it was found.

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 Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

. 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 The Brahmaputra is a trans-boundary river which flows through Tibet, northeast India, and Bangladesh. It is also known as the Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, Luit in Assamese, and Jamuna River in Bangla. It ...

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''.

Distribution and habitat

''Roscoea cangshanensis'' has been found only in one location, in the Cang Shan mountains in

, where it occurs at 2,600 metres in damp soil under pines.

References

{{Taxonbar, from=Q7367548 cangshanensis Plants described in 2007 Endemic flora of Yunnan