Gossypium arboreum
Encyclopedia
Gossypium arboreum, commonly called tree cotton, is a species of cotton
native to India
and Pakistan
and other tropical and subtropical regions of the Old World
. There is evidence of its cultivation as long ago as the Harappan civilization of the Indus Valley for the production of cotton textiles. This species of cotton was also introduced into East Africa and was grown by the Meroe
civilization in Nubia
. The shrub was included in Linnaeus's Species Plantarum
published in 1753. The holotype
was also supplied by him, which is now in the Linnean Herbarium in the Swedish Museum of Natural History
.
. The blades are ovate to orbicular in shape and have 5 to 7 lobes, making them superficially resemble a maple
leaf. The lobes are linear to lanceolate, and often a tooth is present in the sinus. Gland
s are present along the midrib or occasionally on the adjacent nerves. The leaves are glabrescent, meaning the pubescence is lost with age, but when it is present on young leaves, it is both stellate (i.e. star-shaped) and simple.
The flower
s are set on short pedicel
s (i.e. flower stalks). An epicalyx is present, which is a series of subtending bract
s that resemble sepal
s. It has large, ovate segments that are dentate (i.e. toothed along the margins), though sometimes only very slightly so. They are cordate (i.e. heart-shaped) at the base and acute at the apex. The true calyx is small, measuring only about 5 mm in length. Its shape is cupular, and there are 5 subtle dentations present. The corolla is a pale yellow on colour, sometimes with a purple centre, and occasionally entirely purple. It measures 3 to 4 cm in length. The staminal
tube bears the anthers and is 1.5 to 2 cm in length. The fruit
is a 3 to 4 celled capsule measuring 1.5 to 2.5 cm across. It is ovoid or oblong in shape and glabrous (i.e. hairless). The surface is pitted and a beak is present at the termnial end. The seeds within are globular and are covered in long white cotton
.
Gossypium
Gossypium is the cotton genus. It belongs to the tribe Gossypieae, in the mallow family, Malvaceae, native to the tropical and subtropical regions from both the Old and New World. The genus Gossypium comprises around 50 species , making it the largest in species number in the tribe Gosssypioieae....
native to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
and other tropical and subtropical regions of the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
. There is evidence of its cultivation as long ago as the Harappan civilization of the Indus Valley for the production of cotton textiles. This species of cotton was also introduced into East Africa and was grown by the Meroe
Meroë
Meroë Meroitic: Medewi or Bedewi; Arabic: and Meruwi) is an ancient city on the east bank of the Nile about 6 km north-east of the Kabushiya station near Shendi, Sudan, approximately 200 km north-east of Khartoum. Near the site are a group of villages called Bagrawiyah...
civilization in Nubia
Nubia
Nubia is a region along the Nile river, which is located in northern Sudan and southern Egypt.There were a number of small Nubian kingdoms throughout the Middle Ages, the last of which collapsed in 1504, when Nubia became divided between Egypt and the Sennar sultanate resulting in the Arabization...
. The shrub was included in Linnaeus's Species Plantarum
Species Plantarum
Species Plantarum was first published in 1753, as a two-volume work by Carl Linnaeus. Its prime importance is perhaps that it is the primary starting point of plant nomenclature as it exists today. This means that the first names to be considered validly published in botany are those that appear...
published in 1753. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
was also supplied by him, which is now in the Linnean Herbarium in the Swedish Museum of Natural History
Swedish Museum of Natural History
The Swedish Museum of Natural History , in Stockholm, is one of two major museums of natural history in Sweden, the other one being located in Gothenburg....
.
Description
Tree cotton is a shrub attaining heights of 1 to 2 metres. Its branches are covered with pubescence and are purple in colour. Stipules are present at the leaf base and they are linear to lanceolate in shape and sometimes falcate (i.e. sickle-shaped). The leaves are attached to the stem by a 1.5 to 10 cm petiolePetiole (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...
. The blades are ovate to orbicular in shape and have 5 to 7 lobes, making them superficially resemble a maple
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
leaf. The lobes are linear to lanceolate, and often a tooth is present in the sinus. Gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
s are present along the midrib or occasionally on the adjacent nerves. The leaves are glabrescent, meaning the pubescence is lost with age, but when it is present on young leaves, it is both stellate (i.e. star-shaped) and simple.
The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are set on short pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
s (i.e. flower stalks). An epicalyx is present, which is a series of subtending bract
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 often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s that resemble sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s. It has large, ovate segments that are dentate (i.e. toothed along the margins), though sometimes only very slightly so. They are cordate (i.e. heart-shaped) at the base and acute at the apex. The true calyx is small, measuring only about 5 mm in length. Its shape is cupular, and there are 5 subtle dentations present. The corolla is a pale yellow on colour, sometimes with a purple centre, and occasionally entirely purple. It measures 3 to 4 cm in length. The staminal
Stamen
The stamen is the pollen producing reproductive organ of a flower...
tube bears the anthers and is 1.5 to 2 cm in length. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a 3 to 4 celled capsule measuring 1.5 to 2.5 cm across. It is ovoid or oblong in shape and glabrous (i.e. hairless). The surface is pitted and a beak is present at the termnial end. The seeds within are globular and are covered in long white cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
.
External links
- Public domain photo (copyright expired) of Gossypium arboreum (flickr.com)