Vitex rotundifolia
(beach vitex)

Pictures

Picture	Title	Caption	Copyright
Title Flowers and foliage Caption Vitex rotundifolia (beach vitex); flowers and foliage. Kanaha Beach, Maui, Hawaii, USA. November, 2006. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Flowers and foliage	Vitex rotundifolia (beach vitex); flowers and foliage. Kanaha Beach, Maui, Hawaii, USA. November, 2006.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex, Pohinahina); habit, showing stems and foliage. Kanaha Beach, Maui, Hawaii, USA. November, 2004. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex, Pohinahina); habit, showing stems and foliage. Kanaha Beach, Maui, Hawaii, USA. November, 2004.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex, Pohinahina); habit, showing foliage, flowers and fruits. Kanaha Beach, Maui, Hawaii, USA. November, 2006. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex, Pohinahina); habit, showing foliage, flowers and fruits. Kanaha Beach, Maui, Hawaii, USA. November, 2006.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex, Pohinahina); habit. Uprange, Kahoolawe, Hawaii, USA. July, 2003. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex, Pohinahina); habit. Uprange, Kahoolawe, Hawaii, USA. July, 2003.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex); habit, showing well established plant, with strong, woody, stems. Papohaku, Molokai, Hawaii, USA. May, 2005. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex); habit, showing well established plant, with strong, woody, stems. Papohaku, Molokai, Hawaii, USA. May, 2005.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex); colonizing habit. USDA Plant Materials Center, Molokai, Hawaii, USA. July, 2012. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex); colonizing habit. USDA Plant Materials Center, Molokai, Hawaii, USA. July, 2012.	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Vitex rotundifolia (beach vitex, Pohinahina); colonizing habit. Papohaku, Molokai, Hawaii, USA. May, 2005. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Vitex rotundifolia (beach vitex, Pohinahina); colonizing habit. Papohaku, Molokai, Hawaii, USA. May, 2005.	©Forest Starr & Kim Starr - CC BY 4.0
Title Flowers and fruit Caption Vitex rotundifolia (beach vitex, Pohinahina); flowers and fruit. Hoolawa Farms, Maui, Hawaii, USA. November, 2006. Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Flowers and fruit	Vitex rotundifolia (beach vitex, Pohinahina); flowers and fruit. Hoolawa Farms, Maui, Hawaii, USA. November, 2006.	©Forest Starr & Kim Starr - CC BY 4.0

Identity

Preferred Scientific Name

• Vitex rotundifolia L. f.

Preferred Common Name

• beach vitex

Other Scientific Names

• Vitex agnus-castus var. ovata Kuntze
• Vitex ovata Thunberg
• Vitex repens Blanco
• Vitex rotundifolia forma albescens Linnaeus f.
• Vitex rotundifolia forma albiflora S. S.
• Vitex rotundifolia forma rosea Satomi
• Vitex trifolia subsp. litoralis Steenis
• Vitex trifolia var. obovata Bentham
• Vitex trifolia var. ovata Makino
• Vitex trifolia var. simplicifolia Chamisso
• Vitex trifolia var. unifoliolata Schauer

International Common Names

• English: creeping vitex; roundleaf chastetree
• French: gatilier à feuilles simples
• Chinese: dan ye man jing; manjingzi

Local Common Names

• China: viticus fructus
• Japan: hamagô
• Korea, Republic of: man hyung ja
• USA/Hawaii: hinahina kolo; kolokolo kahakai; manawanawa; mawanawana; pohinahina; polinalina

EPPO code

• VIXRO (Vitex rotundifolia)

Summary of Invasiveness

Vitex rotundifolia, commonly known as beach vitex, is a low, woody, perennial shrub with branches that can run for many meters. It is native to Asia, including China and Japan, and also to Oceania, including Australia and Papua New Guinea. It has been introduced to the USA where it has been reported as detrimental to dune ecosystems in seven of the southeastern states since the early 2000s. Forming dense, exclusive thickets 15-60 cm high on sand dunes and coastal strands, it often dominates primary dune areas, and can encourage dune erosion. Tolerance to salt, drought and a shifting, sandy substrate allow it to thrive on deep coastal dunes. According to Hu et al. (2007), V. rotundifolia has been protected as a Threatened species in Shiga Prefecture of Honshu, Japan, and was also included in the List of the Important Wild Plants for Conservation in China in 1989. It is currently on the Florida Exotic Pest Plant Council’s list of invasive plants (FLEPPC, 2015).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Lamiales
•                         Family: Lamiaceae
•                             Genus: Vitex
•                                 Species: Vitex rotundifolia

Notes on Taxonomy and Nomenclature

The genus Vitex was designated by C. Linnaeus Sr. in 1753. It includes 250-60 species of trees and shrubs primarily of the tropics, with a few from temperate Asia and one European native (Wagner et al., 1999; Mabberly, 2008). Although sometimes placed in the family Verbenaceae, the genus Vitex is a clear member of the Lamiaceae based on its laterally attached ovules and rbcL and ndhF molecular sequences; characters which are considered monophyletic for the Lamiaceae (Labiatae) (Judd et al., 2002). Within the Lamiaceae, Vitex is placed in the polyphyletic subfamily Viticoideae along with Gmelina, Callicarpa, Premna, Cornutia and other relatives (Judd et al., 2002).

C. Linnaeus Jr. described V. rotundifolia based on type material from Japan. It is related to, but distinct from and thereby not synonymous with Vitex trifolia L. (Wagner et al., 1999).

Description

Description from Munir (1987), Flora of China Editorial Committee (2016) and Wagner et al. (1999):

A prostrate shrub 10-40 (-90) cm high, spreading to about 10-20 m diameter.

Stems prostrate to creeping, rooting at the nodes. Young branches silky-tomentose. Branches terete or obscurely 4-sided when mature.

Leaves mostly 1-foliolate, rarely a few 2- or 3- 5-7 (-9) foliolate, sessile or with short petioles. Blade obovate-oval, broadly oblong-elliptic, orbicular, or obovate-spatulate, 2.5-5 cm long, 1.5-3 cm broad; base tapering to rounded, margin entire, apex abruptly subacuminate to rounded; abaxial (lower) surface velvety to minutely silky tomentose, adaxial (upper) surface usually pale dull green and pubescent; pair of nerves 4-6.

Inflorescence mostly abbreviate, terminal thyrse borne on small side-branches, 3-10 (-13) cm long, 1-2.5 cm wide; densely tomentose; cymes with short peduncules, usually branched, arranged in a pyramidal panicle.

Flowers zygomorphic with short pedicels; pedicels densely glandular and tomentose, 0.5-2 mm long; bracteoles linear, 1-2.5 mm long. Calyx tube cylindrical, 3-4 mm long, 2-3 mm diam. at the top, 5-ribbed outside with 5 short teeth at the top; glandular and silky-tomentose outside, glabrous within.

Corolla purplish-mauve to lilac-blue; tubular below, tube abruptly spreading, 2-lipped and 5-lobed above; glandular and silky-tomentose outside, villous inside the tube and on the lower half of the large anterior lobe of the lower-lip; the anterior lobe broadly elliptic or almost orbicular in outline, glabrous in the upper inner half and along the periphery outside, 3-5 (-6) mm long, 3-5 mm broad; the two lateral lobes more or less oblong-elliptic or elliptic-ovate, 2-3 (-4) mm long, 1.5-3 (-3.5) mm broad at the base; the two lobes of the upper lip oblong-ovate, 2-3 (-4) mm long, 1.5-3 (-3.5) mm broad. Tube cylindrical below, gradually enlarged upwards, almost twice the length of the calyx, 4-7 mm long, 2-4 mm broad at the top.

Stamens exserted, connate to the corolla-tube; filaments filiform, the anterior pair 7-9 mm long, the lateral pair 6.5-8 mm long; anthers elliptic-oblong in outline, ± 1 mm long, lobes oblong, free and divergent in the lower half.

Ovary globose, glabrous, densely glandular all over, 1-1.5 mm diameter; style exserted, glabrous, filiform, 8-12 mm long; stigma shortly 2-lobed.

Fruit a globose fleshy drupe. Green when fresh, bluish purple to black when ripe, becoming dark-brown when dry; glabrous, glandular all over; 4-5.5 mm long, 5-6.5 mm diameter; fruiting calyx glandular and tomentose outside, glabrous within; 5-toothed, 5-6.5 mm diameter. The seeds are difficult to remove from the fruit.

Plant Type

Distribution

V. rotundifolia has a widespread native range including temperate coastal areas of Japan, Korea and China to Southeast Asia, the Pacific Islands, Australia, and Hawaii (USA).  

A common sandy seashore species in Japan, V. rotundifolia also occurs inland at Lake Biwa, an ancient freshwater lake that was established ca. 400 mya and harbors coastal plant taxa (Setoguchi et al., 2010).

The introduced distribution of V. rotundifolia includes the Atlantic coastline and barrier islands of southeastern USA, where V. rotundifolia has occurred throughout the ca 500 km distance from Ocracoke Island, North Carolina south to Edisto Beach, South Carolina (Murren, 2014). Scattered occurrences, some severe, have been and continue to be found along the Atlantic coasts of Maryland, Virginia, Georgia and Florida. Populations on the Gulf of Mexico shorelines of northwestern Florida and Southern Alabama are among the more recent disjunct occurrences.

The Republic of Georgia, USA, has reported V. rotundifolia since at least 2010 in lowlands of this small, but diverse country. Present coverage is estimated at 0.04% of total land mass, yet modeling predictions based on occurrence and bioclimatic data suggest a future coverage increase to 3.66% in (Thalmann et al., 2015).

In Hawaii, USA, V. rotundifolia occurs on all the main islands, except Kaho'olawe (Wagner et al., 1999).

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

The Arboretum of North Carolina State University, USA, originally recommended V. rotundifolia to the nursery industry where it became available in southeastern USA during the mid to late 1980s. There it was promoted for stabilizing shore dunes while at the same time providing unusual flowers and foliage to the landscape. It was planted by homeowners and incorporated into revegetation programs, especially those that followed extensive hurricane damage of frontal dunes in 1989 (Cousins et al., 2010a). Clonal growth and occasional self-starting, adjacent seedlings were observed to contribute to the unexpectedly rapid expansion of planted patches. Spontaneous populations in isolated areas of barrier islands and regional beaches began to occur from seeds and/or stems carried by longshore drift and coastal currents (Murren et al., 2014).

In 2001, V. rotundifolia was first vouchered as naturalized in the USA, from Georgetown County, South Carolina (Hauser et al., 2009). Within ten years, a survey discovered plants at 246 sites in South Carolina and at 621 sites in North Carolina (Cousins et al., 2010a). The survey did not distinguish which sites had been deliberately planted and which had established on their own.

In 2012, V. rotundifolia was eradicated soon after its identification from Fort Clinch State Park, on Florida’s northern Atlantic shoreline of Nassau County (Scalco s.n. [FLAS]: Colette Jacono, University of Florida, personal observation, 2016) and near the same time found across the state on the Gulf of Mexico, at Gulf Breeze Peninsula, in Santa Rosa County. Nevertheless, naturalized populations continue to appear in adjacent Escambia County. 22 populations have been located on Santa Rosa Island and one at Perdido Bay (Sanson 1 [FLAS]; FLEPPC, 2014) as they do on Atlantic beaches south to Flagler and Volusia County, Florida where land managers continue to find and manage plants (FLEPPC, 2014). Inland to Putnam County, central Florida, the species has been known to hang on for years in an abandoned garden, with no indication of invasive tendencies (Whitten 4072b [FLAS]).

Introductions

Risk of Introduction

Unless homeowners are aware of its negative impacts on the shoreline, this species - easy to propagate, salt and drought tolerant, low growing, and attractive - might continue to be planted. It also spreads easily via ocean currents to new locations.

USA

Because V. rotuntifolia is not prohibited by the USA federal government, interstate trade remains without regulation and the flow of new genotypes into the country remains uninterrupted. Legislation by individual states and municipalities has become even more important for regulating trade, possession and movement.

Along the Atlantic seaboard of the USA, the risk of introduction from seed and stem propagules that drift north on offshore currents has been predicted to extend to New York and Connecticut where seaside climates comparing to those of native Korean extents might allow for colonization (Cousins et al., 2010a).

V. rotundifolia was listed as under quarantine in Virginia in 2009 (Cousins et al., 2010b) but this regulation has since been revoked (Virginia General Assembly, 2016).

Habitat

In the southeastern USA, V. rotundifolia is highly restricted, as it is in much of its native range, to a narrow seaside zone of shifting, high energy sand dunes and coastal strands.  The species has been evaluated at the arboretum of North Carolina State University since 1978 (Olsen and Bell, 2005) and has been planted in gardens inland (Whitten 4072b, FLAS; Hauser et. al, 2009), but has only been known to escape cultivation, grow aggressively, and invade natural habitats along sandy, energy driven coastlines.

Habitat List

Host Plants and Other Plants Affected

Growth Stages

Biology and Ecology

Genetics

Chromosome number:  2n = 32 (Wagner et al., 1999).

Throughout its widespread native range V. rotundifolia demonstrates a good deal of variability including leaf shape and the number of leaflets. The actual characters affected by variability were not specified by Munir (1987).

In 2008, Hu et al. used inter-simple sequence repeat (ISSR) fingerprinting to study genetic diversity and clonal variation in 14 populations along the China coast. Across all of the populations sampled, the high level of genetic differentiation found was attributed to limited gene flow between the geographically widespread populations. Within populations the genotypic diversity found was greater than expected for a clonal species, indicating significant sexual reproduction occurred within the populations. Also, within populations a clear spatial structure was demonstrated, with gene clusters occurring at approximately 20 m intervals. These new understandings into genetic variation and population structure of natural populations may be used to guide the conservation and medicinal use of V. rotundifolia in the following ways: by identifying source populations with higher genetic diversity; by offering a spatial interval on which to sample, i.e. to avoid collecting from clonal material with identical genotypes (Hu et al., 2008).  Additionally, Hu et al. (2007) used molecular markers to reveal a pattern of genetic variation that aligned with a pattern of medicinal chemical constitutes from the fruits.

Introduced populations of V. rotundifolia southeastern USA, once assayed with RFLP markers, demonstrated clonal variation both within and between populations sampled (Plan, 2008). More recently, ISSR microsatellite markers have been developed to investigate genetic diversity and population structure of V. rotundifolia in its native range. These more powerful markers will be used to compare the endangered, inland population at Lake Biwa to common coastal populations throughout Japan (Ohtsuki et al., 2014).

Reproductive Biology

Sexual and asexual populations occur in both the native and introduced ranges of V. rotundifolia. Two to five, or less years may be expected before an individual matures to reproduce by flowering and fruit (USDA-APHIS, 2013). Approximately 76% of the fruits have been found to contain at least one viable seed, and individual fruits have an average of 1.25 viable seeds (Cousins et al., 2010b; Murren et al.. 2014). The species is considered a prolific seed producer due to the prediction that it may produce 1000 seeds per m² (USDA-APHIS, 2013).

Experimental germination rates in V. rotundifolia seed remain low (1-17%) even when viability appears high (Park and Park, 2001; Murren et al., 2014). Viable seeds have been found in the soil for 1.5-4 years (Cousins et al., 2010b). Patterns in germination of this and related species (Murren et al., 2014) suggest the influence of physical and physiological dormancy in the seed (Cousins et al., 2010b). Dormancy generally allows for entrenchment in habitats and viability in widely dispersed seed, i.e. floating fruits. Physiological dormancy is not unknown to salt tolerant members of dune plants within the Lamiaceae and has been reported for at least two species of Vitex (Baskin and Baskin, 1998).

Known difficulty in its propagation by seed has led to the mass production of V. rotundifolia from micropropagation of nodal shoot. Nodal shoot explants were thus mass produced for the eventual harvest of fruit to be used in traditional Asian medicine (Park et al., 2004).

Physiology and Phenology

The widespread adaptability of V. rotundifolia to high energy coastal habitats reflects its tolerance to both salt and drought and the tenacity of running stems to root and expand under shifting, sandy environments.

V. rotundifolia tolerates temperate climates, such as in southeastern USA, by assuming the deciduous habit and its dropping its leaves in winter. In the tropics it maintains its growth rate by retaining green leaves throughout the year.

In southeastern USA, V. rotundifolia flowers from late spring through to summer, and fruits in late summer through to early autumn.

Environmental Requirements

Specifically a tropical to temperate coastal environment hosting deep sands and shifting substrate as found on coastal sand dunes of shorelines and coastal strand.

In Hawaii, USA, V. rotundifolia occurs to elevations of 15 m (Wagner et al. 1999).
 

Climate

Latitude/Altitude Ranges

Rainfall

Rainfall Regime

Soil Tolerances

Soil drainage

• free

Soil reaction

• alkaline

Soil texture

• light

Special soil tolerances

• infertile
• saline

Means of Movement and Dispersal

Primary dispersal of V. rotundifolia is naturally by ocean currents and intentionally by humans.

Natural Dispersal

Estuarine river currents, ocean waves, offshore and deep water ocean currents. A thick water repellent cuticle on fruits helps aid dispersal by ocean currents. Ocean currents are believed to be responsible for the pervasiveness of V. rotundifolia throughout the Pacific. It occurs on many volcanic islands, including those that have existed for only a short time (Cousins et al., 2010b).

Vector Transmission (biotic)

Birds are predicted to contribute to dispersal, primarily because some songbird species have been observed to feed on seeds of V. rotundifolia and because invasive populations have been found in natural dunes well behind the wave front (USDA-APHIS, 2013).

Accidental Introduction

Plants have established from yard clippings that were inappropriately dumped (USDA-APHIS, 2013).

Intentional Introduction

Intentional dispersal of V. rotundifolia has been by humans, primarily those owning shoreline property and planting on dunes as a sand binder and/or as an ornamental.

Pathway Causes

Pathway Vectors

Impact Summary

Economic Impact

Along the Atlantic coastal beaches of southeastern USA, large revenues have been spent in eradicating and/or managing invasive populations. Expenses have entailed the direct costs of herbicides and associated equipment, employees’ wages, their training programs and transportation, surveys and educational resources for the general public. Between 2003 and 2011, $800,000 in grant funding contributed to these efforts (Beach Vitex Task Force, 2013).

Environmental Impact

V. rotundifolia was listed as a noxious weed in North Carolina in 2009 (Cousins et al., 2010b) but is not listed on the current State-listed Noxious Weeds List (USDA-NRCS, 2016).

Impact on Habitats

Severely alters native habitat by dominating primary dune areas with dense, sprawling, perennial, woody cover (Beach Vitex Task Force, 2013). Thickets can reach 15-60 cm high.

Occludes photosynthetically active radiation (PAR) from reaching the sand surface. Approximately 90% of PAR is excluded by populations of V. rotundifolia as opposed to 20-40% of PAR by stands of sea oats (Uniola paniculata) a native grass which can be crowded out by V. rotundifolia (Westbrooks and Madsen, 2006; Cousins et al., 2010a).

Encourages dune erosion and reduced dune profile due to its non-fibrous taproot which extends vertically with minimal branching. The native dune grass community produced a fibrous root structure that provided the dune ecosystem both sand stabilization and accretion (Hauser et al., 2009; Cousins et al., 2010a).

Induces hydrophobicity in the sand substrate due to accumulated deposits of cuticular alkanes deposited from overlying leaves and fruits (Cousins et al., 2009). Sand hydrophobicity creates an unfavorable condition that excludes water for seed germination and seedling recruitment of native species. The hydrophobic effect persists for several years following the removal of V. rotundifolia (Cousins et al., 2009).

Impact on Biodiversity

Dominating monocultures of V. rotundifolia greatly reduce the native floristic diversity of grasses and herbaceous plants through shading, physical occlusion, and the development of hydrophobic conditions that inhibit native seedling regeneration (Cousins et al., 2009).

The tangle of woody branches formed by V. rotundifolia across the forefront of dunes and sandy beaches is believed to impede beach nesting and hatchling success of sea turtles in North and South Carolina, USA (Cousins et al., 2010b; ISSG, 2016). The Carolinas are home to a number of sea turtle species which are either US Federally Endangered or Threatened, including: loggerhead (Caretta caretta), green turtle (Chelonia mydas), Kemp's Ridley (Lepidochelys kempii)leatherback (Dermochelys coriacea), and hawksbill (Eretmochelys imbricate)(Cousins et al., 2010b; ISSG, 2016).

Sea-beach amaranth (Amaranthus pumilus) is a US Federally Threatened plant species that can be outcompeted by V. rotundifolia (Westbrooks and Madsen, 2006). A. pumilus is an effective sand binder, building small dunes where it grows on sparsely vegetated lower foredunes and upper strands of non-eroding beaches. It does not grow on well-vegetated sites and so cannot tolerate competition by V. rotundifolia.

Encroachment of V. rotundifolia into critical nesting habitats of migratory shorebirds, such as the US Federally Endangered piping plover (Charadrius melodus) (US Fish and Wildlife Service, 2009), remains an impending threat to species requiring open sand for nesting.

Threatened Species

Social Impact

Beach residents and beach-goers of southeastern USA have shared an alarmed concerned over the spread of this species because of its demonstrated ability to limit their access to recreation, mainly by covering beach entry trails and occluding sandy beaches with woody mats of low growing shrubbery (Beach Vitex Task Force, 2013).

Risk and Impact Factors

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Pioneering in disturbed areas
• Highly mobile locally
• Long lived
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year
• Reproduces asexually
• Has high genetic variability

• Negatively impacts tourism
• Reduced amenity values
• Reduced native biodiversity
• Threat to/ loss of endangered species

• Allelopathic
• Competition - shading
• Rapid growth
• Rooting

• Highly likely to be transported internationally deliberately

Uses

Economic Value

Micro propagation methods have been developed for the mass production of explants to be used in commercial cultivation aimed at growing fruits for traditional Asian medicine (Park et al., 2004). Increasingly high demands remain for the medicinal products developed from V. rotundifolia in China (Hu et al., 2007).

Social Benefit

Pharmacological studies have demonstrated that flavonoids isolated from V. rotundifolia, have anti-inflammatory, antitumor, and analgesic properties (Kobayakawa et al., 2004; Bae et al., 2013; Gao and Chen, 2015). A recent example demonstrated that the flavonoid vitexicarpin significantly reduced vascular inflammation, which leads to atherosclerosis, by inhibiting adhesion molecules that injure the vascular endothelial cells (Lee et al., 2012).

Environmental Services

In Hawaii, USA, V. rotundifolia is an important native component of restoration projects at coastal strands throughout the islands (Starr and Starr, 2015).

Uses List

Environmental

• Erosion control or dune stabilization
• Land reclamation
• Landscape improvement
• Revegetation

General

• Botanical garden/zoo

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical
• Traditional/folklore

Similarities to Other Species/Conditions

In southeastern USA, two small Vitex tree species preceded the naturalization of V. rotundifolia, both having escaped horticultural planting. Strongly upright and branching, Vitex agnus-castus and Vitex negundo are easily distinguished from V. rotundifolia with its prostrate, running, and rooting branches. Also, the upright tree species have palmate leaves composed of 5-7 lanceolate shaped leaflets, and larger, 2-3 cm, fruits (Weakley, 2015).

Wagner et al (1999) clarify that although V. rotundifolia has often been treated as a sub-form of Vitex trifolia, the two differ distinctly in habit and in leaf shape. V. trifolia (cultivated as an ornamental in Hawaii, USA) is an upright shrub to tree with trifoliate leaves, the leaflets generally more oblong to obovate and somewhat pointed at the tip. The occasional occurrence of simple leaves in V. trifolia and trifoliolate leaves in V. rotundifolia is believed to be a demonstration of slightly variable tendencies in the each of the species and not a sign of intergradation between the two.

Like V. rotundifolia, the neo-tropical tree species Vitexcymosa, is known for its water dispersed fruits, which, with the aid of aerenchyma tissue, float in the seasonally inundated floodplains of its indigenous Panamanian and South American tropics (Mabberley, 2008). The fruits of V. cymosa grow to be six times larger than those of V. rotundifolia, have a sweetly edible pulp, and like V. rotundifolia have seeds difficult to separate from the pulp. In habit and form however, V. cymosa differs greatly. It produces a wide, branching canopy over a single, 12-20 m tall trunk and is exploited from the wild for timber or cultivated for shade (Lorenzi et al., 2006).

On beaches of southeastern USA, seedlings of V. rotundifolia might be mistaken for the native silver-leaf croton, (Croton punctatus) (Gresham 2015). A member of the Euphorbiaceae, C. punctatus differs from V. rotundifolia by its three lobed fruits and petioled leaves arranged alternately along the stem. Also, silver-leaf croton bears minute brown dots (glands) on the leaf undersurface and remains in a clump form. It never sends out long running stems as does V. rotundifolia.

In Florida, USA, on coastal dunes from Volusia to the South, V. rotundifolia might initially be mistaken for the native seagrape, Coccoloba uvifera, a woody member of the family Polygonaceae which shares the low shrubby habit of creeping and branching stems. The orbicular leaves of seagrape, however, are 10 times the size of V. rotundifolia (Nelson, 1996) besides having red veins, cordate, hefty bases and an overall smooth, leathery patina.

Prevention and Control

Control

Physical/mechanical control

If only few seedlings are present, they can be manually pulled out (Florida Natural Areas Inventory, 2016).

Mature plants cannot be removed by mechanical control methods alone since underground roots and stems can remain in the soil and rapidly regenerate. Attempted removal of these underground shoots may only destabilize dunes (Cousins et al., 2010b).

Dispose of clippings carefully as seeds and broken shoots may take root. Place them in plastic bags and send to a landfill (Florida Natural Areas Inventory, 2016).

Biological control

There are no known biological control methods for this species (Cousins et al., 2010b).
    
Chemical control

Imazapyr has been shown to be effective when painted onto wounds of V. rotundifolia stems created using a machete. Allow the plants to stay intact for 6 months following treatment. Repeat this process until there is zero regrowth (Cousins et al., 2010b).

Triclopyr has also been successful when used on seedlings and small-caliper resprouts (Cousins et al., 2010b).

References

Bae H; Kim Y; Lee E; Park S; Jung KH; Gu MJ; Hong SP; Kim J, 2013. Vitex rotundifolia L prevented airway eosinophilic inflammation and airway remodelling in an ovalbumin-induced asthma mouse model. International Immunology, 25(3):197-205.

Baskin CC; Baskin JM, 1998. Seeds: ecology, biogeography, and evolution of dormancy and germination. San Diego, USA: Academic Press, xiv+666 pp.

Beach Vitex Task Force, 2013. Beach Vitex News and Archives. South Carolina, USA: North Inlet-Winyah Bay National Estaurine Research Reserve. www.northinlet.sc.edu/beachvitex/

BISH, 2016. Herbarium Pacificum - Bishop Museum. Honolulu, Hawaii, USA. http://www.bishopmuseum.org/

BO, 2016. Herbarium Bogoriense - Research Centre for Biology. Cibinong, Indonesia.

BRI, 2016. Queensland Herbarium. Queensland, Australia. http://www.qld.gov.au/environment/plants-animals/plants/herbarium/specimens/

Cousins MM; Briggs J; Gresham C; Whetstone J; Whitwell T, 2010. Beach vitex (Vitex rotundifolia): an invasive coastal species. Invasive Plant Science and Management, 3(3):340-345. http://www.wssa.net

Cousins MM; Briggs J; Whitwell T; Gresham C; Whetstone J, 2010. Reestablishment potential of beach vitex (Vitex rotundifolia) after removal and control efforts. Invasive Plant Science and Management, 3(3):327-333. http://www.wssa.net

Cousins MM; Gresham CA; Riley MB; Whitwell T, 2009. Beach dune sand hydrophobicity due to the presence of beach vitex (Vitex rotundifolia L. f.). Journal of Agricultural and Food Chemistry, 57(2):409-415. http://pubs.acs.org/journals/jafcau/index.html

FLAS, 2014. University of Florida Herbarium Collections Catalog. Gainesville, Florida, USA: Museum of Natural History. http://www.flmnh.ufl.edu/herbarium/cat/

FLEPPC, 2014. FLEPPC Plant List Committee Documentation of the Criteria used in Determination of Category I and Category II Invasive Species. Florida, USA: Florida Exotic Pest Plant Council. http://www.fleppc.org/list/2015/criteria_Vitex-rotundifolia.pdf

FLEPPC, 2015. Florida Exotic Pest Plant Council's 2015 list of invasive plant species, 4 pp. http://www.fleppc.org/list/2015FLEPPCLIST-LARGEFORMAT-FINAL.pdf

Flora of China Editorial Committee, 2016. Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

Florida Museum of Natural History, 2015. University of Florida Herbarium Collections Catalog. Gainesville, Florida, USA. http://www.flmnh.ufl.edu/herbarium/cat/

Florida Natural Areas Inventory, 2016. Invasive species: Vitex rotundifolia - beach vitex. Florida, USA: Florida Natural Areas Inventory. http://www.fnai.org/Invasives/Vitex_rotundifolia_FNAI.pdf

Gao X; Chen G, 2015. Isolation, identification and cytotoxic activity analysis of polymethoxylated flavonoids from Vitex rotundifolia fruit. Journal of Plant Resources and Environment, 24(2):118-120.

Georgia Department of Natural Resources, 2009. Georgia Invasive Species Strategy. Social Circle, Georgia, USA: Wildlife Resources Division. http://georgiawildlife.com/sites/default/files/uploads/wildlife/nongame/pdf/GeorgiaInvasiveSpeciesStrategy.pdf

Glenn S; Moore G, 2009. New York Non-Native Plant Invasiveness Ranking Form - Vitex rotundifolia. New York, USA: New York Invasive Species Information. http://www.nyis.info/user_uploads/bf8f1_Vitex.rotundifolia.NYS.pdf

Gresham CA, 2015. Identifying and Managing beach vitex. South Carolina, USA: Clemson Cooperative Extension Service. http://www.clemson.edu/extension/hgic/pests/weeds/hgic2315.html

Hauser C; Rosenberg L; Perry JE, 2009. First record of the exotic invasive Vitex rotundifolia (Verbenaceae) in Virginia. Banisteria, 34:45-47.

HN, 2016. National Center for Natural Sciences and Technology Herbarium. Hanoi, Vietnam.

Hu Yuan; Zhang QiaoYan; Xin HaiLiang; Qin LuPing; Lu BaoRong; Rahman K; Zheng HanChen, 2007. Association between chemical and genetic variation of Vitex rotundifolia populations from different locations in China: its implication for quality control of medicinal plants. Biomedical Chromatography, 21(9):967-975. http://www3.interscience.wiley.com/cgi-bin/abstract/114230945/ABSTRACT?CRETRY=1&SRETRY=0

Hu Yuan; Zhu Yu; Zhang QiaoYan; Xin HaiLiang; Qin LuPing; Lu BaoRong; Rahman K; Zheng HanChen, 2008. Population genetic structure of the medicinal plant Vitex rotundifolia in China: implications for its use and conservation. Journal of Integrative Plant Biology, 50(9):1118-1129. http://www.blackwell-synergy.com/loi/jipb

Imada C, 2012. Bishop Museum Technical Report 60. Hawaiian Native and Naturalized Vascular Plants Checklist. Honolulu, Hawaii, USA. http://hbs.bishopmuseum.org/publications/pdf/tr60.pdf

Invasive Plant Atlas of the United States, 2015. Invasive Plant Atlas of the United States. http://www.invasiveplantatlas.org/

ISSG, 2016. Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission. http://www.issg.org/database/welcome/

Judd WS; Campbell CS; Kellogg EA; Stevens PF; Donoghue MJ, 2002. Plant Systematics: a Phylogenetic Approach. Second Edition. Sunderland, Massachusetts, USA: Sinauer Associates, 576 pp.

Kobayakawa J; Sato-Nishimori F; Moriyasu M; Matsukawa Y, 2004. G2-M arrest and antimitotic activity mediated by casticin, a flavonoid isolated from Viticis Fructus (Vitex rotundifolia Linne fil.). Cancer Letters, 208(1):59-64.

L, 2016. National Herbarium Nederland - Naturalis. Lieden, Netherlands. https://science.naturalis.nl/en/collection/naturalis-collections/botany/

LE, 2016. Komarov Botanical Institute Herbarium. Saint Petersburg, Russia. http://www.binran.ru/

Lee S; Lee Y; Kim Y; Kim J; Kang D; Lee H, 2012. Vascular protective role of vitexicarpin isolated from Vitex rotundifolia in human umbilical vein endothelial cells. Inflammation, 35(2):584-593.

Lorenzi H; Bacher L; Lacerda M; Sartori S, 2006. Brazilian Fruits and Cultivated Exotics. Nova Odessa, Brazil: Plantarum Institute of Plant Studies, 672 pp.

Mabberley DJ, 2008. Mabberley's plant-book: a portable dictionary of plants, their classifications and uses, Ed.3 [ed. by Mabberley, D. J.]. Cambridge, UK: Cambridge University Press, xviii + 1021 pp.

McAvoy WA, 2011. Potential Invaders of Non-native, Invasive Plants in Delaware. Delaware Natural Heritage and Endangered Species Program, Delaware Division of Fish and Wildlife. http://www.dnrec.delaware.gov/fw/NHESP/Documents/Potential%20Invaders%2028%20Dec%202011.pdf

MEL, 2016. National Herbarium of Victoria - Royal Botanic Gardens Victoria. http://www.rbg.vic.gov.au/

MO, 2016. Missouri Botanical Garden Herbarium. Missouri, USA. http://www.missouribotanicalgarden.org/plant-science/plant-science/resources/herbarium.aspx

Munir AA, 1987. A taxonomic revision of the genus Vitex L (Verbenaceae) in Australia. Journal of Adelaide Botanical Garden, 10:31-79.

Murren CJ; Purvis KG; Glasgow D; Messervy J; Penrod M; Strand AE, 2014. Investigating lag phase and invasion potential of Vitex rotundifolia: a coastal dune exotic. Journal of Coastal Research, 30(4):815-824. http://www.bioone.org/loi/coas

Nelson G, 1996. The Shrubs and Woody Vines of Florida: A Reference and Field Guide. Sarasota, Florida, USA: Pineapple Press.

North Carolina Department of Agriculture and Consumer Services, 2015. North Carolina Noxious Weeds List. Raleigh, North Carolina, USA: Plant Industry Division - Plant Protection Section. http://www.ncagr.gov/plantindustry/plant/weed/noxweed.htm

Ohtsuki T; Shoda T; Kaneko Y; Setoguchi H, 2014. Development of microsatellite markers for Vitex rotundifolia (Verbenaceae), an endangered coastal plant in Lake Biwa, Japan. Applications in Plant Sciences, 2(4):1300100. http://www.bioone.org/doi/full/10.3732/apps.1300100

Olsen RT; Bell AC, 2005. History of beach vitex cultivation: a potential invasive ornamental. In: Proceedings of the 50th Annual Southern Nursery Association Research Conference. Atlanta, Georgia, USA: Southern Nursery Association, 531-533.

Park C; Park E, 2001. Growing characteristics and propagation of Vitex rotundifolia for development of rehabilitation plant in seaboard area. Korean Journal of Environment and Ecology, 15(1):57-68.

Park H; Min B; Cha H, 2004. Mass production of sand dune plant, Vitex rotundifolia via micropropagation. Journal of Plant Biotechnology, 6(3):165-169.

Plan A, 2008. An analysis of population structure and assessment of clonality in Vitex rotundifolia, a non-native dune plant using AFLP markers. Master's Thesis. Charleston, South Carolina, USA: College of Charleston.

Setoguchi H; Ishibashi N; Fujita K; Matsubara H; Terada K; Yagi H, 2010. Leaf blade thickness differentiation between coastal and freshwater populations of the coastal plant Vitex rotundifolia (Verbenaceae). Bulletin of the National Museum of Nature and Science. Series B, Botany, 36(2):39-42. http://ci.nii.ac.jp/vol_issue/nels/AA12231458_en.html

Song CS, 1989. List of the Important Wild Plants for Conservation in China. Beijing, China: Chinese Forestry Press.

Starr F; Starr K, 2015. Plants of Hawaii. Makawao, Hawaii, USA: Starr Environmental. http://www.starrenvironmental.com/resources/

Thalmann DJK; Kikodze D; Khutsishvili M; Kharazishvili D; Guisan A; Broennimann O; Müller-Schärer H, 2015. Areas of high conservation value in Georgia: present and future threats by invasive alien plants. Biological Invasions, 17(4):1041-1054. http://link.springer.com/article/10.1007%2Fs10530-014-0774-2

University of West Florida, 2015. Voucher specimen data from the Michael Cousens Herbarium. Pensacola, Florida, USA: UWF.

US Fish and Wildife Service, 2009. Piping plover (Charadrius melodus). 5-Year Review: Summary and Evaluation., USA: US Fish and Wildlife Service. http://www.fws.gov/northeast/endangered/PDF/Piping_Plover_five_year_review_and_summary.pdf

US Fish and Wildlife Service, 1996. Recovery Plan for seabeach amaranth (Amaranthus pumilus) Rafinesque. Atlanta, Georgia, USA.

USDA-APHIS, 2013. Weed risk assessment for Vitex rotundifolia Lf (Lamiaceae) - Beach vitex. Raleigh, North Carolina, USA. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/Vitex_rotundifolia_WRA.pdf

USDA-ARS, 2015. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2016. Introduced, Invasive and Noxious Plants. USA: USDA Natural Resources Conservation Centre. http://plants.usda.gov/java/noxiousDriver

Virginia General Assembly, 2016. Legislative Information System: Virginia Administrative Code. Virginia, USA: Virginia General Assembly. http://leg1.state.va.us/000/reg/TOC02005.HTM#C0316

Wagner WL; Herbst DR; Sohmer SH, 1999. Manual of the flowering plants of Hawaii. Revised edition. Honolulu, Hawaii, USA: University of Hawaii Press/Bishop Museum Press, 1919 pp.

Weakley AS, 2015. Flora of the Southern and Mid-Atlantic States. Chapel Hill, North Carolina, USA: University of North Carolina Herbarium. http://www.herbarium.unc.edu/seflora/

Westbrooks RG; Madsen J, 2006. Federal Regulatory Weed Risk Assessment Beach Vitex (Vitex rotundifolia L. f.) Assessment Summary., USA: USGS BRD; Mississippi State University. http://www.northinlet.sc.edu/beachvitex/media/bv_risk_assessment.pdf

Wunderlin RP; Hansen BF, 2015. Atlas of Florida vascular plants. Tampa, Florida, USA: Institute for Systematic Botany, University of South Florida. http://www.florida.plantatlas.usf.edu/

Links to Websites

Principal Source

Draft datasheet under review

Contributors

26/01/2016 Original text by:

Colette Jacono, Consultant, University of Florida

Distribution Maps