Vitex rotundifolia
Encyclopedia
Vitex rotundifolia is a species of Vitex that is native to seashores throughout the Pacific. Its range includes continents and islands stretching from India east to Hawaii and from Korea south to Australia. This woody perennial plant typically grows approximately 1 m in height. It has a sprawling growth habit and produces runners that root regularly at nodes. This rooting pattern allows the plant to spread rapidly. At maturity, V. rotundifolia produces blue-purple flowers that are borne in clusters and ultimately yield small brown-black fruits. Its leaves are rounded at the tips with green upper surfaces and silver lower surfaces. While the plant is a seashore obligate, it grows over a wide latitude range. It has been used for medicinal purposes throughout its native range. More recently, it was imported to the eastern United States where it has become a seashore invasive. Control efforts are presently underway to protect the fragile beach dune ecosystem.
that can grow as tall as 1.5 m though it typically ranges from 0.5 to 1 m in height. As a product of its rapid nodal rooting, the plant can form dense mats reaching in excess of 10 m from the parent plant. New stems are green, square and fleshy initially before maturing brown and woody. Older, large-diameter stems are covered with heavily fissured bark. Running horizontal stems produce frequent upright branches. Leaves are strongly aromatic, intensifying when crushed. The majority of leaves are simple
, but they can occasionally be palmate trifoliate or 2-leaved. Leaves measure 2 to 6.5 cm in length and 1-4.5 cm in width. Leaf margins are entire
. The leaf shape varies from ovate to obovate with acute
bases and obtuse
apexes. Occasionally, leaf apexes are acute
or emarginate. Upper leaf surfaces are dark green whereas lower leaf surfaces range in color from silver to white to light green; all leaf surfaces are tomentose
. Petiole
bases are typically somewhat purple and measure 0 to 1 cm in length. Blades are cupped downward slightly. Leaf veins are lighter green than surrounding tissue. Flowers are borne in indeterminate
panicles that may be terminal
or axillary
. Infloresences measure 3 to 7 cm in length. The calyx is cup-shaped and 4 to 4.5 cm long. Flowers are zygomorphic, purple to blue-purple, and short pedunculate. They are two-lipped and funnel-form (measuring 8 mm in length). Four stamens are didynamous and extend beyond the corolla tube (measuring 9 to 10 mm). The style extends beyond the stamens (total length: 12 mm) . Pollen is tricolpate
. Ovaries
consist of two carpels with each containing two single seeded locules
. Fruits are globose drupes that are green while immature but turn yellow and red before maturing to bluish black. The fruits are frequently incorrectly characterized in the literature as "seeds
or berries". Each drupe contains a maximum of four seeds though there are usually fewer as a result of seed abortion. Each seed is encapsulated in a separate compartment. Endosperm
is absent. Seeds germinate into tender seedlings that bear two cotyledons and quickly develop two red-margined true leaves. Ploidy
level is 2n = 32, 34*.
and subfamily Viticoideae
. The plant was originally described by the son of Carolus Linnaeus
, Carl Linnaeus the Younger The original description was published in Supplementum Plantarum
in 1782. The generic epithet, Vitex, is derived from the Latin viere, meaning “to bind or twist” in reference to the rope-like stems produced by some species in the genus. The specific epithet, rotundifolia, is derived from the Latin rotundus, which means "round, spherical", and folium, meaning "leaf.” This is a reference to the rounded character of the leaves.
save those in the subfamily Verbenoideae were recently moved to the family Lamiaceae
. As a result of this reorganization, two monophyletic families were established from the paraphyletic Verbenaceae and polyphyletic Lamiaceae. This new classification scheme was initially proposed by Cantino in 1992. Subsequent cpDNA analysis, rbcL sequence analysis, chemotaxonomic studies, and morphological analyses have supported the original logic for family reorganization.
This revision has resulted in some confusion regarding the classification of V. rotundifolia in the literature. Despite the fact that the revision is well supported with volumes of data, many authors continue to incorrectly place the plant in Verbenaceae.
English speaking countries
China
Japan
Korea
Hawaii
and Vitex rotundifolia have been developed at the Chicago Botanic Garden
. These cultivars have undergone successful trials at Longwood Gardens
. The characteristics of the hybrids are more like those of V. rotundifolia than V. agnus-castus. However, the hybrids are more upright than V. rotundifolia and have been described as "open and spreading." The leaf characteristics are intermediate between the two parent plants while the blue-purple flower color of the parents persists in the hybrid.
This plant's natural range includes much of the Pacific Rim
and many of the Pacific islands. The plant was observed by Munir from Northern and Western Australia, New Guinea, Indonesia, New Caledonia, Polynesia, Hawaii, Malaya, Philippines, and Hong Kong. Moldenke reported V. rotundifolia in Brazil, Mauritius, Reunion, Bangladesh, Sri Lanka, Andaman Islands, China, Taiwan, Japan, Ryukyu Islands, Korea, Indochina, Thailand, Borneo, and Sarawak. The plant has also been observed in southern India. Cultivation of V. rotundifolia has been reported in England, Florida, Germany, the Hawaiian Islands, Hong Kong, Java, Johnston Island, Maryland, and New York. At present in the United States, beach vitex has become naturalized only in southeastern states along the east and gulf coasts.
and tropical areas of the Pacific. In temperate areas, the plant is deciduous
and loses its leaves during the cool nights of fall. In the southeastern United States, leaves emerge in April while flowering occurs from June-August with fruiting following shortly thereafter. Fruits may remain attached to the plant into the early spring. V. rotundifolia is capable of overwintering on the dunes in South and North Carolina and in gulf coastal areas. It can survive in USDA hardiness zones 6b to 10.
, which would make self pollination unlikely. Abe reported V. rotundifolia flowers on Nishino-shima Island were visited by flies, honey bees, beetles, butterflies, and ants though most of the visitors were ants. Diverse groups of pollinators visit the flowers in search of the 0.5 µl/flower nectar reward. Due to this wide range of visitors, it is unlikely the plant would require a specialist insect to mediate successful pollination.
mechanism. This dormancy mechanism is made up of a physical dormancy component and a physiological dormancy component. The physical dormancy mechanism is believed to be inforced at least in part by cuticular alkanes that prevent water penetration.. The mechanism of the physiological dormancy component is not yet fully understood. This dormancy mechanism allows for the establishment of a substantial soil seed bank that is capable of surviving and producing new seedlings in excess of 4 years after all vegetation has been removed. Dormancy mechanisms also allow the plant to undergo long-distance dispersal.
beach vitex inhabits. Since the populations are largely clonal
, this may enhance genetic drift
. Significant variations have been observed with regard to geneotype and chemotype
of various beach vitex samples collected from across China. Genotypic and chemotypic variations were closely associated. Large genetic variation between populations was observed with lower variation within populations, and plants within 20 m of each other were closely related. It was believed that differentiation of separated populations might be the cause of variations between populations.
.
. This plant dominates dune ecosystems leading to a reduction in the prevalence of native species. Native species exclusion is of particular concern because some of the species that share a niche
with V. rotundifolia, such as sea beach amaranth (Amaranthus pumilus
Rafinesque), are presently listed as threatened.
V. rotundifolia fruits have been shown to transfer cuticular alkanes to the sand substrate. This results in intense sand hydrophobicity that persists in the soil for many years. This hydrophobicity might negatively impact dune recovery or serve as a means for limiting growth of native plant species.
Sea turtle conservation groups have publicized concerns that dense V. rotundifolia growth may prevent sea turtles from reaching acceptable nesting sites. These same organizations believe that V. rotundifolia may limit the ability of baby turtles to reach the ocean after they hatch. A recent USA Today article mentioned these concerns as part of an effort to raise awareness of V. rotundifolia, as has at least one review article. However, these concerns have not been validated scientifically. Several sea turtle species nest along the coasts of the Carolinas. These include the endangered loggerhead turtle (Caretta caretta), the endangered green turtle (Chelonia mydas), and the critically endangered Kemp's Ridley
(Lepidochelys kempii). If scientific evidence is found to support claims that V. rotundifolia harms sea turtles, this threat would constitute a substantial environmental issue.
Beach vitex emits large amounts of methyl chloride from its leaves. V. rotundifolia was one of the six highest emitting species of 33 possessing this characteristic. A total of 187 species were examined. Methyl chloride is produced naturally, but may be responsible for a substantial portion of the negative impacts on the stratospheric ozone layer
.
Virginia has enacted a quarantine
of its coastal counties (effective 10/26/09) to limit further V. rotundifolia spread.
At least 12 municipalities in North and South Carolina have enacted ordinances that ban V. rotundifolia planting and require homeowners to remove established plantings from their property .
. A 5.25 % solution of imazapyr
is applied to the wounded areas of the stems. After a period of 6 months, all stems are removed. This treatment procedure is repeated until zero regrowth is observed. Triclopyr
may be used to treat small resprouts and seedlings.
Description
V. rotundifolia is a sprawling shrubShrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
that can grow as tall as 1.5 m though it typically ranges from 0.5 to 1 m in height. As a product of its rapid nodal rooting, the plant can form dense mats reaching in excess of 10 m from the parent plant. New stems are green, square and fleshy initially before maturing brown and woody. Older, large-diameter stems are covered with heavily fissured bark. Running horizontal stems produce frequent upright branches. Leaves are strongly aromatic, intensifying when crushed. The majority of leaves are simple
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....
, but they can occasionally be palmate trifoliate or 2-leaved. Leaves measure 2 to 6.5 cm in length and 1-4.5 cm in width. Leaf margins are entire
Entire
*In philately, see Cover*In mathematics, see Entire function*In animal fancy and animal husbandry, entire indicates that an animal has not been desexed, that is, spayed or neutered...
. The leaf shape varies from ovate to obovate with acute
Acute
Acute may refer to:* Acute accent* Acute angle* Acute * Acute * Acute toxicity...
bases and obtuse
Obtuse
Obtuse may refer to:* Obtuse angle, an angle of between 90 and 180 degrees,* Obtuse triangle, a triangle with an internal angle of between 90 and 180 degrees,* leaf shape,* Linguistic ambiguity, lacking sharpness or quickness of sensibility....
apexes. Occasionally, leaf apexes are acute
Acute
Acute may refer to:* Acute accent* Acute angle* Acute * Acute * Acute toxicity...
or emarginate. Upper leaf surfaces are dark green whereas lower leaf surfaces range in color from silver to white to light green; all leaf surfaces are tomentose
Tomentose
Tomentose is a term used to describe plant hairs that are flattened and matted, forming a woolly coating known as tomentum. Often the hairs are silver or gray-colored...
. Petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
bases are typically somewhat purple and measure 0 to 1 cm in length. Blades are cupped downward slightly. Leaf veins are lighter green than surrounding tissue. Flowers are borne in indeterminate
Indeterminate growth
In biology and especially botany, indeterminate growth refers to growth that is not terminated in contrast to determinate growth that stops once a genetically pre-determined structure has completely formed. Thus, a plant that grows and produces flowers and fruit until killed by frost or some other...
panicles that may be terminal
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...
or axillary
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...
. Infloresences measure 3 to 7 cm in length. The calyx is cup-shaped and 4 to 4.5 cm long. Flowers are zygomorphic, purple to blue-purple, and short pedunculate. They are two-lipped and funnel-form (measuring 8 mm in length). Four stamens are didynamous and extend beyond the corolla tube (measuring 9 to 10 mm). The style extends beyond the stamens (total length: 12 mm) . Pollen is tricolpate
Tricolpate
Tricolpate refers to a subclassification of the "Eudicot" monophyletic group, the "true dicotyledons" Tricolpate refers to a subclassification of the "Eudicot" monophyletic group, the "true dicotyledons" Tricolpate refers to a subclassification of the "Eudicot" monophyletic group, the "true...
. Ovaries
Ovary (plants)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...
consist of two carpels with each containing two single seeded locules
Locule
A locule is a small cavity or compartment within an organ or part of an organism ....
. Fruits are globose drupes that are green while immature but turn yellow and red before maturing to bluish black. The fruits are frequently incorrectly characterized in the literature as "seeds
SEEDS
SEEDS is a voluntary organisation registered under the Societies Act of India....
or berries". Each drupe contains a maximum of four seeds though there are usually fewer as a result of seed abortion. Each seed is encapsulated in a separate compartment. Endosperm
Endosperm
Endosperm is the tissue produced inside the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This makes endosperm an important source of nutrition in human diet...
is absent. Seeds germinate into tender seedlings that bear two cotyledons and quickly develop two red-margined true leaves. Ploidy
Ploidy
Ploidy is the number of sets of chromosomes in a biological cell.Human sex cells have one complete set of chromosomes from the male or female parent. Sex cells, also called gametes, combine to produce somatic cells. Somatic cells, therefore, have twice as many chromosomes. The haploid number is...
level is 2n = 32, 34*.
Taxonomy
Vitex rotundifolia is a member of the family LamiaceaeLamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
and subfamily Viticoideae
Viticoideae
Viticoideae is one of the seven subfamilies of Lamiaceae-The Genera of Viticoideae:This subfamily contains the following 10 genera:* Cornutia L.* Gmelina L.* Paravitex Fletcher* Petitia Jacq.* Pseudocarpidium Millsp....
. The plant was originally described by the son of Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
, Carl Linnaeus the Younger The original description was published in Supplementum Plantarum
Supplementum Plantarum
Supplementum Plantarum Systematis Vegetabilium Editionis Decimae Tertiae, Generum Plantarum Editiones Sextae, et Specierum Plantarum Editionis Secundae, commonly abbreviated to Supplementum Plantarum Systematis Vegetabilium or just Supplementum Plantarum, and further abbreviated by botanists to...
in 1782. The generic epithet, Vitex, is derived from the Latin viere, meaning “to bind or twist” in reference to the rope-like stems produced by some species in the genus. The specific epithet, rotundifolia, is derived from the Latin rotundus, which means "round, spherical", and folium, meaning "leaf.” This is a reference to the rounded character of the leaves.
Family level classification
Vitex and all other members of the family VerbenaceaeVerbenaceae
Verbenaceae, commonly known as the verbena family or vervain family, is a family of mainly tropical flowering plants. It contains trees, shrubs and herbs notable for heads, spikes, or clusters of small flowers, many of which have an aromatic smell.Recent phylogenetic studies have shown that...
save those in the subfamily Verbenoideae were recently moved to the family Lamiaceae
Lamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
. As a result of this reorganization, two monophyletic families were established from the paraphyletic Verbenaceae and polyphyletic Lamiaceae. This new classification scheme was initially proposed by Cantino in 1992. Subsequent cpDNA analysis, rbcL sequence analysis, chemotaxonomic studies, and morphological analyses have supported the original logic for family reorganization.
This revision has resulted in some confusion regarding the classification of V. rotundifolia in the literature. Despite the fact that the revision is well supported with volumes of data, many authors continue to incorrectly place the plant in Verbenaceae.
Species level classification
Recent revisions of the genus Vitex have placed V. rotundifolia in synonomy with V. trifolia subsp. littoralis Steenis. Previous researchers have placed V. rotundifolia within V. trifolia. Moldenke (1958) placed V. rotundifolia in synonymy with V. trifolia var. simplicifolia. The placement of Moldenke was in disagreement with Corner (1939), which held V. rotundifolia as distinct from V. trifolia. The placement of Corner was subsequently supported by several authors: Fosberg (1962), Munir (1987), and Wagner (1999).Common Names
Likely due to the wide range over which V. rotundifolia is native, the plant has acquired a host of common names.English speaking countries
- Beach vitex
- Round-leaved chaste tree
- Single-leaf chaste tree
- Chasteberry
- Monk’s pepper
China
- Dan ye man jing
Japan
- Hamagou
Korea
- Man Hyung Ja
Hawaii
- Kolokolo kahakai
- Hinahina kolo
- Manawanawa
- Mawanawana
- Pohinahina
- Polinalina
Hybrids
Multiple hybrids between Vitex agnus-castusVitex agnus-castus
Vitex agnus-castus, also called Vitex, Chaste Tree, Chasteberry, Abraham's Balm or Monk's Pepper, is a native of the Mediterranean region. It is one of the few temperate-zone species of Vitex, which is on the whole a genus of tropical and sub-tropical flowering plants...
and Vitex rotundifolia have been developed at the Chicago Botanic Garden
Chicago Botanic Garden
Located at 1000 Lake Cook Road, Glencoe, Illinois, USA, the Chicago Botanic Garden is a living plant museum situated on nine islands featuring 24 display gardens and surrounded by four natural habitats: McDonald Woods, Dixon Prairie, Skokie River Corridor, and Lakes and Shores. The Garden is open...
. These cultivars have undergone successful trials at Longwood Gardens
Longwood Gardens
Longwood Gardens consists of over 1,077 acres of gardens, woodlands, and meadows in Kennett Square, Pennsylvania, United States in the Brandywine Creek Valley...
. The characteristics of the hybrids are more like those of V. rotundifolia than V. agnus-castus. However, the hybrids are more upright than V. rotundifolia and have been described as "open and spreading." The leaf characteristics are intermediate between the two parent plants while the blue-purple flower color of the parents persists in the hybrid.
Distribution and habitat
V. rotundifolia grows along sandy and rocky coasts from 0 to 15 m above sea level. Plants grow down to the ocean waves themselves. V. rotundifolia is highly tolerant of the harsh beach dune environment characterized by intense heat, high wind, coarse-textured soil, and elevated salinity.This plant's natural range includes much of the Pacific Rim
Pacific Rim
The Pacific Rim refers to places around the edge of the Pacific Ocean. The term "Pacific Basin" includes the Pacific Rim and islands in the Pacific Ocean...
and many of the Pacific islands. The plant was observed by Munir from Northern and Western Australia, New Guinea, Indonesia, New Caledonia, Polynesia, Hawaii, Malaya, Philippines, and Hong Kong. Moldenke reported V. rotundifolia in Brazil, Mauritius, Reunion, Bangladesh, Sri Lanka, Andaman Islands, China, Taiwan, Japan, Ryukyu Islands, Korea, Indochina, Thailand, Borneo, and Sarawak. The plant has also been observed in southern India. Cultivation of V. rotundifolia has been reported in England, Florida, Germany, the Hawaiian Islands, Hong Kong, Java, Johnston Island, Maryland, and New York. At present in the United States, beach vitex has become naturalized only in southeastern states along the east and gulf coasts.
Biology and Ecology
Beach vitex is a perennial that grows throughout the summer months in temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
and tropical areas of the Pacific. In temperate areas, the plant is deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
and loses its leaves during the cool nights of fall. In the southeastern United States, leaves emerge in April while flowering occurs from June-August with fruiting following shortly thereafter. Fruits may remain attached to the plant into the early spring. V. rotundifolia is capable of overwintering on the dunes in South and North Carolina and in gulf coastal areas. It can survive in USDA hardiness zones 6b to 10.
Growth
The plant grows rapidly, and reproduces through vegetative means. As the plant matures, it begins to flower. After maturation, the plant produces large numbers of fruits (up to 5581 fruits per square meter).Pollination
Insect visitation is the likely method of pollen transfer due to the spatial separation of the anthers and stigmaStigma (botany)
The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. The stigma receives pollen at pollination and it is on the stigma that the pollen grain germinates. The stigma is adapted to catch and trap pollen with various hairs, flaps, or sculpturings...
, which would make self pollination unlikely. Abe reported V. rotundifolia flowers on Nishino-shima Island were visited by flies, honey bees, beetles, butterflies, and ants though most of the visitors were ants. Diverse groups of pollinators visit the flowers in search of the 0.5 µl/flower nectar reward. Due to this wide range of visitors, it is unlikely the plant would require a specialist insect to mediate successful pollination.
Dormancy
Evidence indicates that beach vitex possesses a combinational dormancyDormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
mechanism. This dormancy mechanism is made up of a physical dormancy component and a physiological dormancy component. The physical dormancy mechanism is believed to be inforced at least in part by cuticular alkanes that prevent water penetration.. The mechanism of the physiological dormancy component is not yet fully understood. This dormancy mechanism allows for the establishment of a substantial soil seed bank that is capable of surviving and producing new seedlings in excess of 4 years after all vegetation has been removed. Dormancy mechanisms also allow the plant to undergo long-distance dispersal.
Dispersal
There is substantial supportive evidence of a water-based dispersal mechanism for beach vitex fruits. V. rotundifolia plants are present throughout the Pacific including coastal areas of two continents and many islands. Bird dispersal is highly unlikely as there is no fleshy fruit reward; water dispersal is the most likely dispersal means capable of enabling dispersal over such long distances. Fruits are covered with thick coatings of hydrophobic cuticular alkanes allowing them to resist water penetration for extended periods. Researchers have observed V. rotundifolia fruits floating on rivers and oceans.Genetic Diversity
Genetic diversity within populations has been found to be much lower than the average for most woody plants. Additionally, the divergence between populations was found to be higher. There were large genetic differences between populations, indicating there is limited gene flow between populations. This is understandable due to the limited ecological nicheEcological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
beach vitex inhabits. Since the populations are largely clonal
Clonal interference
Clonal interference is a phenomenon in the population genetics of an asexually reproducing organism. It occurs when two beneficial mutations arise independently in different individuals in a genetically homogeneous population. In the absence of genetic recombination, the mutations cannot join to...
, this may enhance genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
. Significant variations have been observed with regard to geneotype and chemotype
Chemotype
Introduced by Pierre Franchomme in 1975 and formalized in the European Union in 2006 with the adoption of the regulation REACH, a chemotype is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites...
of various beach vitex samples collected from across China. Genotypic and chemotypic variations were closely associated. Large genetic variation between populations was observed with lower variation within populations, and plants within 20 m of each other were closely related. It was believed that differentiation of separated populations might be the cause of variations between populations.
Medicinal Uses
V. rotundifolia has found many medicinal uses. These uses generally parallel those of Vitex agnus-castusVitex agnus-castus
Vitex agnus-castus, also called Vitex, Chaste Tree, Chasteberry, Abraham's Balm or Monk's Pepper, is a native of the Mediterranean region. It is one of the few temperate-zone species of Vitex, which is on the whole a genus of tropical and sub-tropical flowering plants...
.
Environmental Concerns
In areas where it has been introduced outside of its native range, V. rotundifolia has proven to be an invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
. This plant dominates dune ecosystems leading to a reduction in the prevalence of native species. Native species exclusion is of particular concern because some of the species that share a niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
with V. rotundifolia, such as sea beach amaranth (Amaranthus pumilus
Amaranthus pumilus
Amaranthus pumilus, the seaside amaranth or seabeach amaranth, is a species of amaranth. This annual plant is now a threatened species, although it was formerly scattered along the eastern coast of the United States, its native range....
Rafinesque), are presently listed as threatened.
V. rotundifolia fruits have been shown to transfer cuticular alkanes to the sand substrate. This results in intense sand hydrophobicity that persists in the soil for many years. This hydrophobicity might negatively impact dune recovery or serve as a means for limiting growth of native plant species.
Sea turtle conservation groups have publicized concerns that dense V. rotundifolia growth may prevent sea turtles from reaching acceptable nesting sites. These same organizations believe that V. rotundifolia may limit the ability of baby turtles to reach the ocean after they hatch. A recent USA Today article mentioned these concerns as part of an effort to raise awareness of V. rotundifolia, as has at least one review article. However, these concerns have not been validated scientifically. Several sea turtle species nest along the coasts of the Carolinas. These include the endangered loggerhead turtle (Caretta caretta), the endangered green turtle (Chelonia mydas), and the critically endangered Kemp's Ridley
Kemp's Ridley
Kemp's ridley sea turtle , or Atlantic ridley sea turtle is the rarest sea turtle and is critically endangered. It is one of two living species in the genus Lepidochelys Kemp's ridley sea turtle (Lepidochelys kempii), or Atlantic ridley sea turtle is the rarest sea turtle and is critically...
(Lepidochelys kempii). If scientific evidence is found to support claims that V. rotundifolia harms sea turtles, this threat would constitute a substantial environmental issue.
Beach vitex emits large amounts of methyl chloride from its leaves. V. rotundifolia was one of the six highest emitting species of 33 possessing this characteristic. A total of 187 species were examined. Methyl chloride is produced naturally, but may be responsible for a substantial portion of the negative impacts on the stratospheric ozone layer
Ozone layer
The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...
.
Legislation
In light of the invasive characteristics of V. rotundifolia, it has been added to the North Carolina Noxious Weed List (effective 2/1/2009). Plants on this list are effectively banned within the state in that possession, sale, and transport of these species is illegal.Virginia has enacted a quarantine
Quarantine
Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....
of its coastal counties (effective 10/26/09) to limit further V. rotundifolia spread.
At least 12 municipalities in North and South Carolina have enacted ordinances that ban V. rotundifolia planting and require homeowners to remove established plantings from their property .
Control Measures
Initially, beach vitex stems are wounded using a macheteMachete
The machete is a large cleaver-like cutting tool. The blade is typically long and usually under thick. In the English language, an equivalent term is matchet, though it is less commonly known...
. A 5.25 % solution of imazapyr
Imazapyr
Imazapyr is a non-selective herbicide used for the control of a broad range of weeds including terrestrial annual and perennial grasses and broadleaved herbs, woody species, and riparian and emergent aquatic species....
is applied to the wounded areas of the stems. After a period of 6 months, all stems are removed. This treatment procedure is repeated until zero regrowth is observed. Triclopyr
Triclopyr
Triclopyr is a systemic, foliar herbicide in the pyridine group. It is used to control broadleaf weeds while leaving grasses and conifers unaffected....
may be used to treat small resprouts and seedlings.
External Links
- Species Profile- Beach Vitex (Vitex rotundifolia), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for Beach Vitex.