Senega lewtonii

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Senega lewtonii
Polygalalewtonii.jpg
Status TNC G3.svg
Vulnerable  (NatureServe)
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Polygalaceae
Genus: Senega
Species:
S. lewtonii
Binomial name
Senega lewtonii
(Small) J.F.B.Pastore & J.R.Abbott
Synonyms
  • Polygala lewtoniiSmall

Senega lewtonii is a rare species of flowering plant in the milkwort family known by the common name Lewton's polygala, or Lewton's milkwort. It is endemic to Florida in the United States, where it is limited to the central ridge of the peninsula. There are about 49 occurrences of the plant remaining. [1] Most occurrences contain very few plants. The species is threatened by the loss and degradation of its habitat. [2] This is a federally listed endangered species of the United States.

Contents

Description

The plant is a short-lived perennial herb producing erect, fleshy stems from the top of its taproot. The stems grow up to 20 centimeters tall. The leaves are alternately arranged and overlapping, with a number of small leaves in the axil of one larger leaf. They are linear to spatula-shaped and about a centimeter long. The top of each stem is occupied by a short inflorescence of flowers. [2] There are three types of flowers on this plant. [1] [3] The most obvious is the chasmogamous type borne in the inflorescence on the stem. These are each half a centimeter long with pink winglike sepals and three smaller tufted pink petals at the center. The second type of flower is cleistogamous and borne at the base of the plant. These do not open, but self-pollinate. These flowers, which occur at the leaf axils, are rare. [4] The third type of flower is a cleistogamous, unopening type that remains underground. [1] These are borne on a stalk up to 40 centimeters long which is located just below the surface of the soil. [5] They are white in color, [4] and also self-pollinate. [1] The very uncommon mode of reproduction characterized by aboveground chasmogamous flowers and belowground cleistogamous flowers is called amphicarpy and it is known from fewer than 100 plant species. [5] The different types of flowers may occur at different times of the year. [1] The aboveground flowers depend on insect pollinators for successful reproduction, as evidenced by the low fruit production of flowers in a pollinator-exclusion experiment. [4] Pollinators include bee-flies, flower flies, and leaf-cutter bees. [1] The fruit is a capsule containing cylindrical seeds each about 0.3 centimeters long. [2] The seeds have hairs which attract ants, [4] which then collect and disperse them. [2] The most common type of seed-collecting ant is Pheidole morrissii and others include Paratrichina arenavaga and P. phantasma . [1]

Distribution

This species grows on the sandhills of Central Florida and the transition between sandhill and Florida scrub. The land is dominated by longleaf pine, turkey oak, and other oaks. It can also be found in recently cleared areas such as the dry, open clearings around power lines. [2] The substrate is yellow sand. [5] Other endangered plant species in the habitat include Warea amplexifolia , Ziziphus celata , Prunus geniculata , and Nolina brittoniana . [6]

Habitat

The habitat occupied by this species is maintained by a natural fire regime. Fire helps the plant by removing competing plants and the buildup of ground litter and lichens. Though the plant is burned in fires, its seedlings sprout in large numbers in the seasons after a large fire, in one case increasing the population by 800%. It is thought that smoke may trigger or foster germination of seeds in the soil seed bank. Fire also benefits the plant by increasing its survival, lowering its age of reproductive maturity, and increasing the density of the plants. [1]

Because fire is beneficial and necessary for the plant, the common practice of fire suppression is a major threat to its survival. [2] The plant declines the longer its habitat goes without a fire. Another major threat to the species is the outright loss of its habitat to development. The yellow-sand sandhill regions are desirable for conversion to citrus groves. Land has also been consumed in rapidly expanding development of residential areas. The destruction of the habitat has resulted in habitat fragmentation. Remaining fragments are popular terrain for off-road vehicle enthusiasts. [1]

Many occurrences of the species are located on land that is now protected. Prescribed burns help to bring the habitat back to its normal state. [1]

Related Research Articles

<i>Polygala</i> Genus of flowering plants

Polygala is a large genus of flowering plants belonging to the family Polygalaceae. They are commonly known as milkworts or snakeroots. The genus is distributed widely throughout much of the world in temperate zones and the tropics. The genus name Polygala comes from the ancient Greek "much milk", as the plant was thought to increase milk yields in cattle.

<i>Platystemon</i> Genus of flowering plants

Platystemon is a monotypic genus of flowering plants in the poppy family containing the single species Platystemon californicus, which is known by the common name creamcups. It is native to Oregon, California, Arizona, Utah and Baja California, and is found in open grasslands and sandy soils below 6,000 feet (1,800 m) elevation.

<i>Eriodictyon capitatum</i> Species of flowering plant

Eriodictyon capitatum, the Lompoc yerba santa, is a rare evergreen shrub in the borage family. It is endemic to western Santa Barbara County, in California.

<i>Bergia texana</i> North American species of flowering plant in the waterwort family

Bergia texana is a species of flowering plant in the waterwort family known by the common name Texas bergia. It is native to the western and central United States and northern Mexico, where it is a plant of wetlands, living in mud and moist soils along the edges of rivers and pools. This is an annual or perennial herb producing a branching, glandular, hairy stem which grows upright or trailing up to 30 centimeters long. The leaves are 2 to 4 centimeters long, mainly oval in shape and pointed, and lightly toothed along the edges. The inflorescences appear at the tips of stem branches and in the leaf axils, bearing single flowers or small clusters. Each small flower has five green sepals and five greenish white petals. Some of the flowers open, while others are cleistogamous, remaining closed and self-pollinating. The fruit is an oval capsule with many seeds in each of its five chambers.

<i>Warea carteri</i> Species of flowering plant

Warea carteri is a species of plant in the mustard family, Brassicaceae, known by the common names Carter's pinelandcress and Carter's mustard. It is an endangered, fire-dependent annual herb occurring in xeric, shrub-dominated habitats on the Lake Wales Ridge of central Florida in the United States.

<i>Rhinotropis californica</i> Species of flowering plant

Rhinotropis californica, synonym Polygala californica, is a species of flowering plant in the milkwort family known by the common name California milkwort. It is native to southwestern Oregon and northern and central California, where it grows in the coastal mountain ranges in local habitat types such as chaparral and forest. It is a perennial herb producing spreading stems, generally decumbent in form, up to about 35 centimeters in maximum length, lined with narrow oval leaves each a few centimeter long. The upper inflorescences produce several open flowers, and there may be some closed, cleistogamous flowers lower on the plant. The open flowers have pink or white winglike lateral sepals with hairy edges. The petals are similar in color, the central one tipped with a white or yellow beak. The fruit is a flattened green capsule up to a centimeter long containing hairy seeds.

<i>Torreyostellaria</i> Species of flowering plant

Torreyostellaria is a genus of flowering plants in the family Caryophyllaceae. It is monotypic, being represented by the single species Torreyostellaria jamesiana, commonly known as tuber starwort and sticky starwort, It is native to much of the western United States, where it can be found in sagebrush, coniferous forests, and many other types of habitat.

<i>Chionanthus pygmaeus</i> Species of flowering plant

Chionanthus pygmaeus is a rare species of flowering plant in the olive family known by the common name pygmy fringetree. It is endemic to Florida, where there are 46 known occurrences as of 2010. The plant is found in increasingly rare habitat in Central Florida that is being consumed for development, and some protected areas are not managed adequately. Most populations are small. It is a federally listed endangered species of the United States.

<i>Clitoria fragrans</i> Species of legume

Clitoria fragrans is a rare species of flowering plant in the legume family known by the common name pigeon wings, or sweet-scented pigeon wings. It is endemic to Central Florida, where it was known most recently from 62 occurrences, but no current estimates of the total global population are available. The plant is a federally listed threatened species of the United States.

<i>Conradina glabra</i> Species of flowering plant

Conradina glabra is a rare species of shrub known by the common names Apalachicola rosemary or Apalachicola false rosemary. It is endemic to Liberty County, Florida, where it is known from about ten populations. It is found only in a small area and it is threatened by habitat destruction. It is a federally listed endangered species.

<i>Lespedeza leptostachya</i> Species of plant

Lespedeza leptostachya is a rare species of flowering plant in the legume family known by the common names prairie lespedeza and prairie bush-clover. It occurs in the Upper Midwest region of the United States. The flowers are creamy-white to purplish and arranged into a narrow terminal spikes.

<i>Lupinus aridorum</i> Species of legume

Lupinus aridorum is a rare species of lupine known by the common name scrub lupine. It is endemic to Florida in the United States, where there were 10 known populations remaining in 2003. Fewer than 6000 individual plants were counted. It is threatened by the loss and degradation of its habitat. The scrub lupine is a federally listed endangered species of the United States.

<i>Lysimachia asperulifolia</i> Species of plant

Lysimachia asperulifolia is a rare species of flowering plant in the Primulaceae known by the common name rough-leaved loosestrife and roughleaf yellow loosestrife. It is endemic to the Atlantic coastal plain in North Carolina and northern South Carolina in the United States, where there are 64 known populations. It is a federally listed endangered species of the United States.

<i>Nolina brittoniana</i> Species of plant

Nolina brittoniana is a rare species of flowering plant in the asparagus family known by the common name Britton's beargrass. It is endemic to Florida, where there are 72 known populations, only a few large enough to be considered viable. It is federally listed as an endangered species of the United States.

<i>Polygala smallii</i> Species of flowering plant

Polygala smallii is a rare species of flowering plant in the milkwort family known by the common name tiny polygala, or tiny milkwort. It is endemic to Florida in the United States, where it is limited to the southeastern coast of the peninsula. The plant is now only known from eight sites, with most individuals located on one site in Miami-Dade County. The species is threatened by the loss of its habitat. This is a federally listed endangered species of the United States.

<i>Warea amplexifolia</i> Species of flowering plant

Warea amplexifolia is a rare species of flowering plant in the mustard family known by the common names wideleaf pinelandcress, wide-leaf warea, and clasping warea. It is endemic to Florida in the United States, where it is limited to a few counties in the central part of the peninsula. It is threatened by the loss and degradation of its habitat. It is a federally listed endangered species of the United States.

<i>Kummerowia stipulacea</i> Species of legume

Kummerowia stipulacea is a species of flowering plant in the legume family known by the common name Korean clover. It is native to China, Japan, Korea, and Russia, and it is present in the eastern United States as an introduced species.

Delphinium viridescens is a species of flowering plant in the buttercup family known by the common name Wenatchee larkspur. It is endemic to central Washington state in the United States, where it occurs in the Wenatchee Mountains in Chelan and Kittitas Counties.

<i>Dichanthelium clandestinum</i> Species of grass

Dichanthelium clandestinum is a species of grass known by the common name deertongue. It is native to eastern North America, including eastern Canada and the eastern United States.

Amphicarpy is a reproductive strategy that occurs with 13 plant families, expressed mostly in species with an annual life cycle. It is characterized by production of two types of fruit, for different ecological roles. It is sometimes restricted to the situation where one fruit type is aerial and the other subterranean (hypogeous), and similar to, but distinguished from, heterocarpy, which latter means a plant that carries two distinct types of fruit or seeds. The word amphicarp is the contraction of the Greek words ἀμφί meaning "of both kinds" and καρπός meaning fruit.

References

  1. 1 2 3 4 5 6 7 8 9 10 USFWS. Polygala lewtonii Five-year Review. August 2010.
  2. 1 2 3 4 5 6 Polygala lewtonii. The Nature Conservancy.
  3. Swift, Joel F.; Smith, Stacy A.; Menges, Eric S.; Bassüner, Burgund; Edwards, Christine E. (2016-12-01). "Analysis of mating system and genetic structure in the endangered, amphicarpic plant, Lewton's polygala (Polygala lewtonii)". Conservation Genetics. 17 (6): 1269–1284. doi:10.1007/s10592-016-0860-3. ISSN   1566-0621.
  4. 1 2 3 4 Weekley, C. W. and A. Brothers. (2006). Failure of reproductive assurance in the chasmogamous flowers of Polygala lewtonii (Polygalaceae), an endangered sandhill herb. Am J Bot 93:245-53.
  5. 1 2 3 U.S. Fish and Wildlife Service, Lewton's polygala (Polygala lewtonii), 5-Year Review: Summary and Evaluation (PDF)
  6. Polygala lewtonii. Archived 2011-10-26 at the Wayback Machine Center for Plant Conservation.