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 in the
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 ...
province of 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 ''R. praecox'', 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. It is sometimes grown as an ornamental plant in gardens.
Description
''Roscoea praecox'' 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 ...
. 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. In the case of ''R. praecox'', the flowers appear before the leaves are fully grown. Plants are usually 7–30 cm tall. The first four or five leaves consist only of a sheath, which has brownish veins. The remaining leaves, which are not developed at flowering time, have a blade, with a very small ligule at the junction of the sheath and blade.
In its native habitats, ''R. praecox'' flowers between April and June. The stem ( peduncle) of the flower spike may either be hidden by the leaf sheaths or protrude. One to three flowers open together and may be of various colours: purple, violet or white. The bracts which subtend the flowers are 4–6.5 cm long.
Each flower has the typical structure for ''
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 ...
'' (see the diagrams in that article). There is a tube-shaped outer calyx, 3–4.5 cm long with a two-toothed apex. 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 tube only just slightly protruding from the calyx, terminating in three more or less equally sized lobes, each around 3 cm long: an upright central lobe and two side lobes. 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, which are rhombic in shape with a narrower base, 1.7–2.5 cm long; two central staminodes are partially fused at the base to form a lip or labellum, 2.5–4 cm long by 1.5–2 cm wide. The labellum bends backwards and is split into two lobes for more than half its length. It has white markings at its narrowed base.
The single functional stamen has a cream
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 ...
with spurs about 7 mm long, formed from the connective tissue between the two capsules of the anther.
Taxonomy
''Roscoea praecox'' was first described scientifically by
Karl Moritz Schumann
Karl Moritz Schumann (17 June 1851 – 22 March 1904) was a German botanist.
Schumann was born in Görlitz. He was curator of the Botanisches Museum in Berlin-Dahlem from 1880 until 1894. He also served as the first chairman of the ''Deutsc ...
, a German botanist, in 1904. The specific epithet ''praecox'' means "early". ''R. praecox'' flowers before the leaves have fully developed.
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. praecox'' falls into the Chinese clade as would be expected from its distribution. It is closely related to '' R. cautleyoides'', '' R. humeana'' and '' R. wardii''.
Distribution and habitat
''Roscoea praecox'' occurs in both shrubby and grassy habitats in mountains between 2,200 and 2,300 metres in the
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 ...
province of China.
Cultivation
Some ''Roscoea'' species and cultivars 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. ''R. praecox'' has been grown at the
Royal Botanic Gardens, Kew
Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,100 ...
, where it flowered between May and July. It does not appear to be as widely cultivated as some other species (e.g. it was not included in the Pacific Bulb Society's information on the genus ), but was part of a
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 ...