Biology
(
Anglèis
)
fornì da Arkive
The Spring Creek bladderpod has an annual life cycle. The plant germinates between September and October and spends the winter as a small rosette of leaves, waiting until the spring before it fully develops and begins to flower. Flowers usually blossom in March and April (4) (5), and once fertilised, the fruit begins to mature and the flowers wither (4). The fruit splits open upon maturity in late April and May and the plant dies shortly after (5). The enclosed seeds fall onto the ground, where they lie dormant until the autumn, at which point the life cycle begins again with seed germination (4).
Like other bladderpods, individual plants of this species are unable to self-fertilise, and reproduction therefore requires cross-pollination with other individuals (5).
Conservation
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Anglèis
)
fornì da Arkive
The Endangered Species Act protects endangered plants on Federal lands, but no known populations of Spring Creek bladderpods are located on federal land. Commercial exploitation or wilful destruction of these plants on privately-owned land is also illegal by anyone other than the landowner, but this law does not prevent landowners from destroying plants on their own land. Furthermore, it is not considered a violation to destroy the plants in the name of public works projects such as road construction, or in the course of routine forestry or agricultural practices. Nevertheless, all landowners have been contacted about the location of Spring Creek bladderpods on their property, and three landowners to date have agreed to protect the plants on their land through various means of management, providing protection for approximately 4,000 plants in total. A Recovery Plan has also recently been formulated for the Spring Creek bladderpod, identifying important targets and management strategies for the future conservation of this rare endemic plant, which will hopefully help ensure its long-term survival in Tennessee (5).
Description
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Anglèis
)
fornì da Arkive
Bladderpods (Lesquerella) earn their unusual name for the inflated, rounded shape of their fruits, or pods (4) (5). The fruit of the Spring Creek bladderpod is somewhere between egg- to pear-shaped, and is smooth to sparsely hairy on the outside, but densely hairy on the inside (2) (5). The flowers are made up of four white to pale-lavender petals, which are yellow at their base, giving the appearance of a yellow centre to the flower (4) (5). A blanket of fine to coarse hairs covers the stems and leaves (5).
Habitat
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Anglèis
)
fornì da Arkive
Typically found on creek floodplains (of Spring Creek, Bartons Creek and Cedar Creek), but also in agricultural fields, flooded pastures and glades (open spaces with few or no trees). This rare species appears to require some degree of annual disturbance to survive, ideally occurring after fertilisation and before germination. Disturbance comes in the form of scouring from natural flooding, or ploughing of the soil on agricultural lands. This disturbance helps remove perennial grasses, herbs and other woody plants (5).
Range
(
Anglèis
)
fornì da Arkive
Confined to a small area within Tennessee's Central Basin in the United States (4).
Status
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Anglèis
)
fornì da Arkive
Classified as Endangered on the IUCN Red List of Threatened Plants 1997 (1) and listed as Endangered on the U.S. Endangered Species Act 1967 (3).
Threats
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Anglèis
)
fornì da Arkive
The continued survival of the Spring Creek bladderpod is threatened by habitat loss in its already limited range, as a result of rapid residential, commercial and industrial development (4) (5). Additional threats include conversion of land to uses other than cultivation of annual crops, such as to pastureland for grazing livestock, and encroachment of the plant's habitat by woody and herbaceous perennials (4) (5). Unless a site is 'disturbed' in some way every few years, populations of this rare plant quickly dwindle, and agriculture has been the primary mechanism by which suitably disturbed habitat has been maintained in the recent past. However, agricultural practices within Tennessee's Central Basin are declining as the demand for residential development increases. Furthermore, the associated construction of new and improved sewer, water and gas lines are often located along streams, precisely the habitat the Spring Creek bladderpod occupies. Any damning or alteration of the three creeks (Spring Creek, Bartons Creek and Cedar Creek) around which it lives pose a further potential threat to the species, since natural flooding is important in dispersal of seeds to newly disturbed sites (5).
Paysonia perforata
(
Anglèis
)
fornì da wikipedia EN
Paysonia perforata, known by the common name Spring Creek bladderpod, is a rare species of flowering plant in the mustard family. It is endemic to Tennessee in the United States, where it is known only from Wilson County.[1] This very rare plant is threatened by the loss and degradation of its habitat.[2] It is federally listed as an endangered species.
Description
This is an annual herb growing mostly erect to a height of 10 to 15 centimeters. The leaves are auriculate (ear-shaped), up to 5 centimeters long by 1.5 wide, and have toothed or lobed edges. They are usually hairy. The flowers have white or lavender petals with a yellow tinge at the bases. The fruit is an inflated silique drying to a papery texture and measuring about half a centimeter wide.[3] This species is similar to Paysonia stonensis, another Tennessee endemic, from which it differs only in the arrangement of hairs on its fruits.[2]
Natural History
This plant only grows in the Central Basin of Tennessee, where there are 21 known occurrences in Wilson County.[2] The occurrences are almost all located on the floodplains of two[1] or three[2] creeks within a five-mile radius of Lebanon. The plant is adapted to a regime of periodic flooding as the creeks swell. The scouring action of the floodwaters maintain a floodplain that is clear of perennial grasses and large or woody vegetation that would otherwise take hold and compete with the bladderpod. Large sections of this floodplain region have been converted to agricultural use, and the soil disturbance created by plowing has replaced the natural disturbance of flooding. Certain agricultural practices do not adversely affect the plant, such as delaying spring plowing until the time of year when the plant has finished its reproduction.[2] The fruit is mature and splits to release seeds in late April and early May.[2] Other practices, such as no-till farming, do not favor the plant's growth because they do not produce the soil disturbance that it would require in nature.[2] Plowing the soil during times of the year when this annual plant has not yet matured and set seed can prevent the species' propagation.[2]
The floodplain soil is silty and overlies limestone substrates. The habitat includes natural floodplains and farm land such as crop fields and pastures. Other rare plants in the Nashville Basin include Boechera perstellata, Dalea foliosa, Dalea gattingeri, and Echinacea tennesseensis.[4]
Conservation
The lack of disturbance in the habitat causes its degradation by allowing the encroachment of large vegetation that crowds out the annual plants. The habitat in this region is being destroyed outright, however, by other processes, particularly the development of residential, commercial, and industrial complexes and associated utilities such as water lines and sewers. The plant's range is on the outer fringe of the Nashville metropolitan area, which is undergoing rapid growth.[2] These threats prompted the addition of this plant to the endangered species list of the US.
References
- licensa
- cc-by-sa-3.0
- drit d'autor
- Wikipedia authors and editors
Paysonia perforata: Brief Summary
(
Anglèis
)
fornì da wikipedia EN
Paysonia perforata, known by the common name Spring Creek bladderpod, is a rare species of flowering plant in the mustard family. It is endemic to Tennessee in the United States, where it is known only from Wilson County. This very rare plant is threatened by the loss and degradation of its habitat. It is federally listed as an endangered species.
- licensa
- cc-by-sa-3.0
- drit d'autor
- Wikipedia authors and editors
Paysonia perforata
(
vietnamèis
)
fornì da wikipedia VI
Paysonia perforata là một loài thực vật có hoa trong họ Cải. Loài này được (Rollins) O'Kane & Al-Shehbaz mô tả khoa học đầu tiên năm 2002.[1]
Chú thích
Liên kết ngoài
- licensa
- cc-by-sa-3.0
- drit d'autor
- Wikipedia tác giả và biên tập viên
Paysonia perforata: Brief Summary
(
vietnamèis
)
fornì da wikipedia VI
Paysonia perforata là một loài thực vật có hoa trong họ Cải. Loài này được (Rollins) O'Kane & Al-Shehbaz mô tả khoa học đầu tiên năm 2002.
- licensa
- cc-by-sa-3.0
- drit d'autor
- Wikipedia tác giả và biên tập viên
