Chigua
Encyclopedia
Chigua is a genus of cycad
s in the family Zamiaceae
containing two species, endemic to small areas in northwestern Colombia
. Described by botanist Dennis Stevenson
in 1990, it is the most recently named genus. Both species are listed as Critically Endangered
by the IUCN Red List
. The genus name comes from a Spanish
transliteration of the common name given to cycads by the indigenous peoples of Colombia. The species are found in wet lowland rainforest
s at 100-200 m altitude.
Plants have a subterranean globose stem. The leaves
emerge singly and are straight, oblong, and pinnately compound. The petiole and rachis
have spines. Leaflet
s are opposite, lanceolate, and jointed at the base. They have a toothed margin with a distinct midrib and forking parallel side veins. Male cones are cylindrical and covered in short hairs. They are held on long erect stalks and have hexagonal sporophyll
s. Female cones are broadly cylindrical and hairy, held on very long peduncle
s two to three times the length of the cone. The female sporophylls are also hexagonal and have distinct bumps. The elliptical seeds are pink or red in color.
Chigua is very closely related to the genus Zamia
. C. restrepoi was collected as early as 1918 by Francis Pennell, but the new species was placed in Zamia. It was not collected again until 1986, and two subsequent collections in 1987 and 1988 became the basis for the establishment of a new genus. Because the genus has only been collected four times, there is little known about its conservation problems. The population sizes for the species are unknown, and nothing is known about the cones or seeds of C. bernalii, which is only known from the 1986 collection. Because political conflict in Colombia has made travelling dangerous there, the genus is unlikely to be well known for a while. Cattle grazing
, mining
, and oil exploration
have threatened the habitat in the region.
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s in the family Zamiaceae
Zamiaceae
The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and warm temperate regions of Africa, Australia and North and South America....
containing two species, endemic to small areas in northwestern Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. Described by botanist Dennis Stevenson
Dennis Stevenson
Dennis Stevenson was an Australian politician with the Abolish Self-Government Coalition party. He was elected to the Australian Capital Territory Legislative Assembly in the inaugural 1989 ACT elections and served under the 1st and 2nd assemblies, retiring in 1995...
in 1990, it is the most recently named genus. Both species are listed as Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....
by the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The genus name comes from a Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
transliteration of the common name given to cycads by the indigenous peoples of Colombia. The species are found in wet lowland rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s at 100-200 m altitude.
Plants have a subterranean globose stem. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
emerge singly and are straight, oblong, and pinnately compound. The petiole and rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
have spines. Leaflet
Leaflet
A leaflet in botany is a part of a compound leaf. A leaflet may resemble an entire leaf, but it is not borne on a stem as a leaf is, but rather on a vein of the whole leaf. Compound leaves are common in many plant families...
s are opposite, lanceolate, and jointed at the base. They have a toothed margin with a distinct midrib and forking parallel side veins. Male cones are cylindrical and covered in short hairs. They are held on long erect stalks and have hexagonal sporophyll
Sporophyll
A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia , or microsporangia...
s. Female cones are broadly cylindrical and hairy, held on very long peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
s two to three times the length of the cone. The female sporophylls are also hexagonal and have distinct bumps. The elliptical seeds are pink or red in color.
Chigua is very closely related to the genus Zamia
Zamia
Zamia is a genus of cycad of the family Zamiaceae, containing around 50 species, native to North, Central and South America. Species occur as far north as Georgia in the United States to as far south as Bolivia Zamia is a genus of cycad of the family Zamiaceae, containing around 50 species, native...
. C. restrepoi was collected as early as 1918 by Francis Pennell, but the new species was placed in Zamia. It was not collected again until 1986, and two subsequent collections in 1987 and 1988 became the basis for the establishment of a new genus. Because the genus has only been collected four times, there is little known about its conservation problems. The population sizes for the species are unknown, and nothing is known about the cones or seeds of C. bernalii, which is only known from the 1986 collection. Because political conflict in Colombia has made travelling dangerous there, the genus is unlikely to be well known for a while. Cattle grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
, mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, and oil exploration
Oil exploration
Hydrocarbon exploration is the search by petroleum geologists and geophysicists for hydrocarbon deposits beneath the Earth's surface, such as oil and natural gas...
have threatened the habitat in the region.