''Roscoea wardii'' 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 ...

occurring from eastern

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

in India to western

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 ...

in China. 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 like other species of ''

Roscoea ''Roscoea'' is a genus of perennial plants of the 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 southern neighbo ...

'', ''R. wardii'' grows in much colder mountainous regions.

Description

''Roscoea wardii'' is a

. Like all members of the genus ''Roscoea'', it grows from a short

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 the tuberous roots are attached. 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 nutrie ...

s" are produced: structures which resemble stems but are actually formed from the tightly wrapped bases (sheaths) of its leaves. ''R. wardii'' reaches a height of 32 cm. There are three to five bladeless sheathing leaves with pink veins and two to three full leaves, 7–8 cm long by 1.7–4.5 cm wide. At the junction of the blade and sheath there are small transparent structures (ligules), 1–2 mm high. The stem ( peduncle) of the flower spike is short, almost absent in some plants. The flowers are typically deep purple in colour, although paler rose-coloured forms are known. Pale green bracts, 3.5–5.5 cm long, surround the base of the flowers. Each flower has the typical structure for ''

'' (see that article for labelled images). There is a tube-shaped outer calyx, about 3.3–4.5 cm long, which emerges from the surrounding bracts. 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 about 4–8 cm long, usually emerging from the calyx, at least when the flowers are mature. The tube terminates in three petal lobes: an upright central lobe and two slightly shorter side lobes. The central lobe is about 2–3.2 cm long by 1.3–2.5 cm wide; the side lobes are considerably smaller, 0.2–0.3 cm long by 0.4–1.4 cm 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 petals, about 1.6–2 cm long by 0.7–1 cm wide, including a short narrowed "claw" at the base. Two central staminodes are fused at the base to form a lip or labellum, about 2.2–4.5 cm long by 1.6–4.5 cm wide. The labellum is deeply lobed and has three white lines at the base of each lobe. The single functional

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 6–9 mm long, and the typical ''Roscoea'' "spurs" on the filament – blunt-tipped in the case of ''R. wardii''. The three-celled ovary is about 3 cm long when matured with seeds.

Taxonomy

''R. wardii'' was first described by Jill Cowley in 1982.

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. wardii'' falls into the Chinese clade as would be expected from its distribution. It is closely related to '' R. cautleyoides'', '' R. humeana'' and '' R. praecox''.

Distribution and habitat

''Roscoea wardii'' is found in mountainous regions along the borders between

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa people, ...

(China),

(India) and

Burma Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Cultivation

''R. wardii'' was included in a trial of ''Roscoea'' held by the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

from 2009 to 2011. It proved hardy with a rating of H4 (hardy though most of the UK apart from inland valleys, at winter altitude and central/northerly locations). It was given the

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

, subject to availability, and currently holds the award.

Notes

References

Bibliography

* {{Taxonbar, from=Q7367565 wardii Plants described in 1982 Flora of Arunachal Pradesh Flora of Myanmar Flora of Yunnan