''Rheum webbianum'' is a species of

herbaceous 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 ...

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 ...

rhubarb Rhubarb is the fleshy, edible stalks ( petioles) of species and hybrids (culinary rhubarb) of ''Rheum'' in the family Polygonaceae, which are cooked and used for food. The whole plant – a herbaceous perennial growing from short, thick rhizo ...

-relative in the family

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus ''Polygonum'', and was first used by Antoine Laurent de Jussieu in 1789 ...

from the southwestern

Himalayan region The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...

, known in (Indian) English as Indian rhubarb, Gilgiti rhubarb or small Himalayan rhubarb.

Taxonomy

The species epithet honours

Philip Barker Webb Philip Barker Webb (10 July 1793 – 31 August 1854) was an English botanist. Life Webb was born to a wealthy, aristocratic family; his father was the lord of the manors of Witley and Milford, Surrey, Milford, in Surrey, England. Webb was e ...

, a botanist from the 19th century. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

is kept at the

herbarium A herbarium (plural: herbaria) is a collection of preserved plant specimens and associated data used for scientific study. The specimens may be whole plants or plant parts; these will usually be in dried form mounted on a sheet of paper (called ...

of the

Liverpool Museum World Museum is a large museum in Liverpool, England which has extensive collections covering archaeology, ethnology and the natural and physical sciences. Special attractions include the Natural History Centre and a planetarium. Entry to the ...

. In the 1998 ''Flora Republicae popularis Sinicae'' A. R. Li classifies ''R. webbianum'' in section ''Rheum'' together with ''R. compactum'', ''R. likiangense'' and ''R. wittrockii''.

Description

Habitus ''Rheum webbianum'' is a

plant which grows from in height. It has a stout, hollow stem bearing the

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

, this is finely sulcate (with many fine fissures in profile) and glabrous (hairless) or covered in

papilla Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Basilar papilla, a sensory organ of lizards, amphibians and fish * Dental papilla, in a developing tooth * Dermal papillae, part of ...

(papilliferous) on the surface of its upper part. This plant is very variable, especially in the leaf size and plant height. Rheum webbianum -Viote 02

Leaves It has a stout, long petiole on its basal leaves which is shorter than blade and papilliferous. Leaves are leathery, and green on the upper side and muricate on the lower, or papillose or glabrous. The shape of the leaf blade is entire, orbicular,

cordate Cordate is an adjective meaning 'heart-shaped' and is most typically used for: * Cordate (leaf shape), in plants * Cordate axe, a prehistoric stone tool See also * Chordate A chordate () is an animal of the phylum Chordata (). All chordat ...

(heart-shaped), reniform-cordate to

reniform Reniform is an adjective meaning "kidney-shaped" and may specifically refer to: * Reniform leaf The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single ...

(kidney-shaped) in shape, long (more usually ), from (more usually ) wide, and with the blade shorter than wide. The leaf blade has five to 7, nearly basal, main veins. The apex (tip) of the leaf blade is obtuse (rounded) or subacute (slightly pointed), the margin is slightly sinuolate (wavy), and the base is broadly cordate. The upper leaves on the inflorescence stem are smaller and are

ovate Ovate may refer to: *Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ovat ...

in shape. Flowers The

is a large, diffusely branched (once or twice), densely-flowered

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

up to 1m tall, with the flower clusters usually axillary, less commonly terminal (at the end of the

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s). The small flowers have no

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s, are pale yellowish in colour, have a diameter of , have a filiform (wiry), 3-5mm long

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

which is jointed below middle, and have elliptic-shaped

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s. Fruit The winged fruit is notched (slightly

retuse The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

) on both ends; the wings are broad, approximately 3.5mm wide, and with longitudinal veins near their margins. The fruit is broadly oblong/ellipsoid or orbicular in shape, 8-12mm across, approximately as long as wide. The seeds are narrowly ovoid-ellipsoid in shape, approximately 4mm wide. Karyotypy ''R. webbianum'' populations apparently are found in both

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

and tetraploid forms, having a

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

count of 2''n''=22 or 2''n''=44. It is suspected that this infraspecific

karyotypic A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

diversity indicates the existence of one or more

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

, despite the different forms being phenotypically identical, because the

polyploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

forms would essentially be reproductively isolated.

Similar species

According to the 2003 key in the ''

Flora of China The flora of China consists of a diverse range of plant species including over 39,000 vascular plants, 27,000 species of fungi and 3000 species of bryophytes.Wu, Z. Y., P. H. Raven & D. Y. Hong, eds. 2006. Flora of China. Vol. 22 (Poaceae). Sc ...

'', this species is distinguished from other entire-leaved rhubarbs in China with leaves having a wavy or crisped margin; ''R. wittrockii'', ''R. rhabarbarum'', ''R. australe'' and ''R. hotaoense'', by having less than 1 cm-sized fruit, yellow-white flowers, and a wider than long leaf blade with a reniform-cordate to cordate shape. In many characters, it is most similar to ''R. rhabarbarum'' and ''R. hotaoense''.

Distribution

This species is present in

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

(

Gilgit-Baltistan Gilgit-Baltistan (; ), formerly known as the Northern Areas, is a region administered by Pakistan as an administrative territory, and constituting the northern portion of the larger Kashmir region which has been the subject of a dispute bet ...

Khyber-Pakhtunkhwa Khyber Pakhtunkhwa (; ps, خېبر پښتونخوا; Urdu, Hindko: خیبر پختونخوا) commonly abbreviated as KP or KPK, is one of the four provinces of Pakistan. Located in the northwestern region of the country, Khyber Pakhtunkhwa ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

(

Kashmir Kashmir () is the northernmost geographical region of the Indian subcontinent. Until the mid-19th century, the term "Kashmir" denoted only the Kashmir Valley between the Great Himalayas and the Pir Panjal Range. Today, the term encompas ...

Uttarakhand Uttarakhand ( , or ; , ), also known as Uttaranchal ( ; the official name until 2007), is a state in the northern part of India. It is often referred to as the "Devbhumi" (literally 'Land of the Gods') due to its religious significance and ...

), western

Nepal Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...

and southwest

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, ...

It is very common in the Himalayas.

Ecology

Habitat

In Pakistan it grows on slopes at an elevation of above sea level. In Tibet it is known from slopes at 3500-3600m elevation. In Nepal it grows at altitudes of 2400-4200m. In India it is known from elevations of 2400-4300m.

Life cycle

It flowers extending from June through September in Pakistan. It flowers June to July in India. It fruits August to September in Tibet.

Local names

In Pakistan it is known as ' in the Gilgit region, and ' in the Chitral valley. An

Urdu Urdu (;"Urdu"
''

Hindi Hindi (Devanāgarī: or , ), or more precisely Modern Standard Hindi (Devanagari: ), is an Indo-Aryan language spoken chiefly in the Hindi Belt region encompassing parts of northern, central, eastern, and western India. Hindi has been de ...

it is called the following names: (Indian rhubarb), or . In

Marathi Marathi may refer to: *Marathi people, an Indo-Aryan ethnolinguistic group of Maharashtra, India *Marathi language, the Indo-Aryan language spoken by the Marathi people *Palaiosouda, also known as Marathi, a small island in Greece See also * * ...

it is known as . It is called ' in

. In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...

it is known as , .

Uses

Like ''

Rheum australe ''Rheum australe'', synonym ''Rheum emodi'', is a flowering plant in the family Polygonaceae. It is commonly known as Himalayan rhubarb, Indian rhubarb and Red-veined pie plant. It is a medicinal herb used in the Indian Unani system of medicine, ...

'', the roots of this species are harvested from the wild to make the drug Indian rhubarb; this was formerly an important drug in Western medicine, and is still used in

Unani Unani or Yunani medicine (Urdu: ''tibb yūnānī'') is Perso-Arabic traditional medicine as practiced in Muslim culture in South Asia and modern day Central Asia. Unani medicine is pseudoscientific. The Indian Medical Association describes U ...

medicine. In Pakistan locals eat the leaf stalk cooked as in the West. The root is used as a purgative. In the Chitral valley the stems of the unripe inflorescence and leaf stalks are also eaten raw for the taste. Poor children collect the plant from the wild to sell in the market for money.

References

{{Taxonbar, from=Q10923670 webbianum