Sextonia
Encyclopedia
Sextonia is a neotropical genus of plant
in Lauraceae
family, South America.
evergreen trees with male and female flowers on separate trees. Occurring in Peru, Brazil: Amapa, Maranhao, Para.
Caribbean: Trinidad and Tobago. Northern South America: French Guiana; Guyana; Suriname; Bolivar in Venezuela.
The genus is characterized by an extremely rare combination of characters that have occured in the species in its own distinct genus. There is little information regarding the species due to its scarcity.
Flowers monoclinic with urceolate hypanthium,.
The fruit is a berry, a small dark drupe
containing a single seed
.
Sextonia consists of two species where occur.
. The ecological requirements of the genus are those of the laurel forest
and like most of their counterparts laurifolia in the world, they are vigorous species with a great ability to populate the habitat that is conducive. The natural habitat is rainforest which is cloud-covered for much of the year. The species is found in forests that face threats of destruction by human deforestation
.
Because of the special lack of worldwide knowledge about the family lauraceae
in general, very little is known about their diversity. Recent monographs of the small and medium genera of lauraceae with up to 100 species per genus have produced a high increase in the number of known species. This high increase is expected for other genera as well, particularly for those with more than 150 species recorded, bringing an expected considerable increase in the total number of species of the family.
A related vegetal community evolved millions of years ago on the supercontinent of Gondwana
, and species of this community are now found on several separate areas of the Southern Hemisphere
, including South America
, Africa
, New Zealand
, Australia
and New Caledonia
.
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
in Lauraceae
Lauraceae
The Lauraceae or Laurel family comprises a group of flowering plants included in the order Laurales. The family contains about 55 genera and over 3500, perhaps as many as 4000, species world-wide, mostly from warm or tropical regions, especially Southeast Asia and South America...
family, South America.
Overview
It is a genus of aromatic dioeciousPlant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
evergreen trees with male and female flowers on separate trees. Occurring in Peru, Brazil: Amapa, Maranhao, Para.
Caribbean: Trinidad and Tobago. Northern South America: French Guiana; Guyana; Suriname; Bolivar in Venezuela.
The genus is characterized by an extremely rare combination of characters that have occured in the species in its own distinct genus. There is little information regarding the species due to its scarcity.
Characteristics
They are evergreen monoecious trees. Large trees to 45 m tall. Twigs thick, corky, terete. Clustered leaves and flowers. Leaves alternate, clustered near te tips of the branches, pinnately veined, without domatia.Flowers monoclinic with urceolate hypanthium,.
The fruit is a berry, a small dark drupe
Drupe
In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...
containing a single seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
.
Sextonia consists of two species where occur.
Ecology
Endemic species of the tropical seasonal semi-deciduous montane forests, Cloud forestCloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...
. The ecological requirements of the genus are those of the laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
and like most of their counterparts laurifolia in the world, they are vigorous species with a great ability to populate the habitat that is conducive. The natural habitat is rainforest which is cloud-covered for much of the year. The species is found in forests that face threats of destruction by human deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
.
Because of the special lack of worldwide knowledge about the family lauraceae
Lauraceae
The Lauraceae or Laurel family comprises a group of flowering plants included in the order Laurales. The family contains about 55 genera and over 3500, perhaps as many as 4000, species world-wide, mostly from warm or tropical regions, especially Southeast Asia and South America...
in general, very little is known about their diversity. Recent monographs of the small and medium genera of lauraceae with up to 100 species per genus have produced a high increase in the number of known species. This high increase is expected for other genera as well, particularly for those with more than 150 species recorded, bringing an expected considerable increase in the total number of species of the family.
A related vegetal community evolved millions of years ago on the supercontinent of Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
, and species of this community are now found on several separate areas of the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
, including South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
.