Charpentiera densiflora
Encyclopedia
Charpentiera densiflora is a rare species of tree
in the amaranth family
known by the common names dense-flowered pāpala and Nā Pali Coast pāpala. It is endemic to the island of Kauai
in Hawaii
, where there are 300 to 400 mature trees remaining. This and many other rare Kauaian plants were added to the endangered species list
of the United States in 2010.
This is a tree growing up to 12 meters tall. It occurs in forests in moist mountain gulches which are dominated by hala
(Pandanus tectorius), a common tree of the Pacific Islands. The leaves are roughly oval in shape and up to 40 centimeters long. The inflorescence
is a branching panicle
of flowers, each main branch bearing up to 100 flowers. Like other plants of its genus, this species is gynodioecious
; most of the plants have bisexual flowers with male and female parts, but some have only female flowers. Some of the female parts in the bisexual flowers are abortive or nonfuctional, indicating that the species is in the middle of an evolution
toward a fully dioecious system; eventually some flowers might start developing without the female parts. If the species becomes dioecious, some individuals will produce all male flowers and some will bear all female. This species has smaller seeds than any other of its genus.
The tree is found only on Kauai, and mainly on the Nā Pali Coast
. There are seven populations. Many of the remaining individuals are in the forests of Hoolulu Valley at around 800 feet in elevation
. The tree sometimes grows alongside Charpentiera elliptica
, and the two species sometimes hybridize. However, the rare dense-flowered pāpala does not seem to be succumbing to the problems involved in hybridization, such as genetic pollution
, as evidenced by its maintaining its numbers without having its population overcome by hybrids. It is possible that ecological isolation
helps protect the tree.
This rare tree is threatened by a number of processes. It was probably much more widespread than it is today. Its habitat has been destroyed and degraded by feral goat
s and pigs, washed out by flood
s, and invaded by a number of non-native plant species
. It experienced damage during Hurricane Iniki
in 1992, which led to erosion
.
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
in the amaranth family
Amaranthaceae
The flowering plant family Amaranthaceae, the Amaranth family, contains about 176 genera and 2,400 species.- Description :Most of these species are herbs or subshrubs; very few are trees or climbers. Some species are succulent....
known by the common names dense-flowered pāpala and Nā Pali Coast pāpala. It is endemic to the island of Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, where there are 300 to 400 mature trees remaining. This and many other rare Kauaian plants were added to the endangered species list
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
of the United States in 2010.
This is a tree growing up to 12 meters tall. It occurs in forests in moist mountain gulches which are dominated by hala
Pandanus tectorius
Pandanus tectorius is a species of Pandanus that is native to Malesia, eastern Australia, and the Pacific Islands. Common names include Thatch Screwpine, Hala , Bacua , and Vacquois ....
(Pandanus tectorius), a common tree of the Pacific Islands. The leaves are roughly oval in shape and up to 40 centimeters long. The inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a branching panicle
Panicle
A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....
of flowers, each main branch bearing up to 100 flowers. Like other plants of its genus, this species is gynodioecious
Plant 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....
; most of the plants have bisexual flowers with male and female parts, but some have only female flowers. Some of the female parts in the bisexual flowers are abortive or nonfuctional, indicating that the species is in the middle of an evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
toward a fully dioecious system; eventually some flowers might start developing without the female parts. If the species becomes dioecious, some individuals will produce all male flowers and some will bear all female. This species has smaller seeds than any other of its genus.
The tree is found only on Kauai, and mainly on the Nā Pali Coast
Na Pali Coast State Park
Nā Pali Coast State Park encompasses of land and is located in the center of the rugged along the northwest side of Kauai, the oldest inhabited Hawaiian island. The Nā Pali coast itself extends southwest starting at Kee Beach extending all the way to Polihale State Park. The pali rise as high as...
. There are seven populations. Many of the remaining individuals are in the forests of Hoolulu Valley at around 800 feet in elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
. The tree sometimes grows alongside Charpentiera elliptica
Charpentiera elliptica
Pāpala is an endangered species of flowering tree in the pigweed family, Amaranthaceae, that is endemic to the island of Kauai in Hawaii. It inhabits coastal mesic and mixed mesic forests at elevations of ....
, and the two species sometimes hybridize. However, the rare dense-flowered pāpala does not seem to be succumbing to the problems involved in hybridization, such as genetic pollution
Genetic pollution
Genetic pollution is a controversial term for uncontrolled gene flow into wild populations. This gene flow is undesirable according to some environmentalists and conservationists, including groups such as Greenpeace, TRAFFIC, and GeneWatch UK.-Usage:...
, as evidenced by its maintaining its numbers without having its population overcome by hybrids. It is possible that ecological isolation
Reproductive isolation
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not...
helps protect the tree.
This rare tree is threatened by a number of processes. It was probably much more widespread than it is today. Its habitat has been destroyed and degraded by feral goat
Feral goat
The feral goat is the domestic goat when it has become established in the wild. Feral goats occur in Australia, New Zealand, Ireland, Great Britain, Hawaii, the Galapagos and in many other parts of the world...
s and pigs, washed out by flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
s, and invaded by a number of non-native plant species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. It experienced damage during Hurricane Iniki
Hurricane Iniki
Hurricane Iniki was the most powerful hurricane to strike the U.S. state of Hawaii in recorded history. Forming on September 5 during the strong El Niño of 1991–1994, Iniki was one of eleven Central Pacific tropical cyclones during the 1992 season. It attained tropical storm status on...
in 1992, which led to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.