Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Oplismenus hirtellus subsp. undulatifolius
(wavyleaf basketgrass)

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Datasheet

Oplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass)

Summary

  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Oplismenus hirtellus subsp. undulatifolius
  • Preferred Common Name
  • wavyleaf basketgrass
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • O. hirtellus subsp. undulatifolius, wavyleaf basketgrass, is a shade-tolerant, perennial grass native to Europe, Asia and India. It has now established itself in the forest understory in the central mi...

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Pictures

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PictureTitleCaptionCopyright
Oplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); infestation,  in a closed-canopy mesic forest, showing typical plant growth habit. Maryland, USA.
TitleInfestation
CaptionOplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); infestation, in a closed-canopy mesic forest, showing typical plant growth habit. Maryland, USA.
Copyright©Kerrie L. Kyde/Maryland Department of Natural Resources/Bugwood.org - CC BY-NC 3.0 US
Oplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); infestation,  in a closed-canopy mesic forest, showing typical plant growth habit. Maryland, USA.
InfestationOplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); infestation, in a closed-canopy mesic forest, showing typical plant growth habit. Maryland, USA.©Kerrie L. Kyde/Maryland Department of Natural Resources/Bugwood.org - CC BY-NC 3.0 US
Oplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); close-up of foliage. Little Paint Branch Park, Prince George's County, Maryland, USA.
TitleFoliage
CaptionOplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); close-up of foliage. Little Paint Branch Park, Prince George's County, Maryland, USA.
Copyright©Kerrie L. Kyde/Maryland Department of Natural Resources/Bugwood.org - CC BY-NC 3.0 US
Oplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); close-up of foliage. Little Paint Branch Park, Prince George's County, Maryland, USA.
FoliageOplismenus hirtellus subsp. undulatifolius (wavyleaf basketgrass); close-up of foliage. Little Paint Branch Park, Prince George's County, Maryland, USA.©Kerrie L. Kyde/Maryland Department of Natural Resources/Bugwood.org - CC BY-NC 3.0 US

Identity

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Preferred Scientific Name

  • Oplismenus hirtellus subsp. undulatifolius (Arduino) U. Scholz 1981

Preferred Common Name

  • wavyleaf basketgrass

Other Scientific Names

  • Hippagrostis undulatifolia Kuntze (1891)
  • Oplismenus africanus var. capensis (Hochst.) Stapf (1899)
  • Oplismenus africanus var. simplex Stapf in W.H.Harvey & auct. suc. (eds.) (1899)
  • Oplismenus capensis Hochstetter (1846)
  • Oplismenus coreanus Nakai (1952)
  • Oplismenus simplex K. Schumann (1894)
  • Oplismenus undulatifolius (Ard.) Roem. & Schult. (1817)
  • Oplismenus undulatifolius P. Beauv. (1812)
  • Oplismenus undulatifolius for. elongatus (Honda) Y.N. Lee (1966)
  • Oplismenus undulatifolius var. binatus S.L. Chen & Y.X. Jin (1984)
  • Oplismenus undulatifolius var. elongatus Honda (1932)
  • Oplismenus undulatifolius var. undulatifolius (Chen & Phillips, 2012)
  • Orthopogon bolosii Vayreda (1931)
  • Orthopogon undulatifolius (Ard.) Spreng. (1824)
  • Orthopogon undulatus Link (1827)
  • Panicum burmannii auct. non Retz. (1804)
  • Panicum hirtellum auct. non L. (1785)
  • Panicum kraussii von Steudel (1853)
  • Panicum undulatifolium Ard. (1764)

Local Common Names

  • China: qiu mi cao
  • Germany: Welligblättrige Grannenhirse; Welligblättriger Geradbart

Summary of Invasiveness

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O. hirtellus subsp. undulatifolius, wavyleaf basketgrass, is a shade-tolerant, perennial grass native to Europe, Asia and India. It has now established itself in the forest understory in the central mid-Atlantic region of the United States and is quickly extending its range (Peterson et al., 1999; Kyde and Marose, 2008; Thompson, 2009; Westbrooks and Imlay, 2009).

The subspecies was reported in Maryland, USA in 1996 and is thought to have been present on the Hawaiian islands for at least 150 years, although misidentification may negate this claim (Snow and Lau, 2008). The perennial grass may also be found in Australia (Atlas of Living Australia, 2012).

The extreme stickiness of the spikelets allows for efficient dispersal of the seeds to new areas by biotic and human vectors but the original mode of introduction is unknown. 

O. hirtellus subsp. undulatifolius poses a major threat to forest ecosystems displacing native herbaceous plants and affecting the regeneration of native hardwood tree species (ISSG, 2012).

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Poaceae
  •                             Genus: Oplismenus
  •                                 Species: Oplismenus hirtellus subsp. undulatifolius

Notes on Taxonomy and Nomenclature

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The uncertainty surrounding accurate identification of Oplismenus hirtellus subsp. undulatifolius (Ard.) U. Scholz is widespread. Scholz (1981), who wrote the still most complete taxonomic treatment of the genus, ascribes the apparent disunity in modern floristic works to the strong polymorphism of the species and the problematic disjunct subtropical range of some taxa in the genus Oplismenus.

Davey and Clayton (1978) addressed the circumscription difficulties of non-distinct definitional boundaries by assigning only three species to the genus: O. hirtellus, O. compositus and O. undulatifolius. Validating Scholz’s (1981) observation that using a classical systematic approach would provide no fully satisfying results, recent genetic analysis strongly suggests that the Scholz circumscription of wavyleaf basketgrass as a subspecies of O. hirtellus may be better described as a species in its own right rather than a subspecies of O. hirtellus (Scholz, 1981; USDA-APHIS PPQ CPHST, 2009). 

But if the genetic analyses show that there is a taxon, then all that is wrong is the decision of Scholz (1981) to treat O. undulatifolius as a subspecies. The consequence of the decision has led, perhaps, to the inclusion of multiple taxa under the name O. hirtellus. It is likely that the current consequent confusion in interpretation of the taxon is in part a result of the use of pressed and dried specimens. The sole use of herbarium specimens makes it harder to identify and recognize distinguishing features (Mary Barkworth, Intermountain Herbarium, Utah State University, personal communication, 2012).

The Maryland and Virginia populations have been positively identified as Oplismenus hirtellus subsp. undulatifolius (Ard.) Scholz and are currently referred to as such (USDA-APHIS PPQ CPHST, 2009; ISSG, 2012; USDA-APHIS PPQ PERAL, 2012). An ornamental variegated pink, green and white form is sold under numerous, varied names such as O. hirtellus ‘Variegatus’, O. africanus 'Variegatus', O. variegatus, O. burmanii 'Variegatus', Panicum variegatum, ‘Ribbon grass’ or ‘basket grass’ for hanging baskets. While some have thought that this variegated ornamental form could revert to the subspecies O. hirtellus subsp. undulatifolius, USDA- APHIS indicates that the reversions to a green form of these widely purchased variegated plants, whether natural or chemically induced, are dissimilar enough morphologically to O. hirtellus subsp. undulatifolius to cast doubt on this possibility (USDA-APHIS PPQ CPHST, 2009; ISSG, 2012). O. hirtellus 'Variegatus' often reverts to an all green form and this reverted phenotype does not resemble O. hirtellus subsp. undulatifoliusO. hirtellus 'Variegatus' according to the USDA CPHST study "lacks leaf trichomes, and has not produced seeds or inflorescences" (USDA-APHIS PPQ CPHST, 2009).

The ornamental variegated Oplismenus found in the florist and nursery trade is not a cultivar or sport of O. hirtellus subsp. undulatifolius. The sterile variegated garden species has been propagated and distributed under numerous names since its introduction to the florist, garden and nursery trade in the mid nineteenth century (Long, 1874).

O. hirtellus subsp. undulatifolius was first described as Panicum undulatifolium by the Italian botanist, Pietro Arduino, in 1764. The great naturalist Palisot de Beauvois assigned P. undulatifolius to the genus Oplismenus (Palisot de Beauvois, 1812).  

Noltie (2000) chooses to refer to this taxon as O. undulatifolius (Ard.) P. Beav. var. undulatifolius commenting that "Scholtz… treated both …as ssp. of O. hirtellus (L.) P. Beav., however, they seem to me to be far closer to O. compositus".

Description

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O. hirtellus subsp. undulatifolius is a stoloniferous perennial, typically reaching 20-30 cm tall. It is a low-growing grass, which branches and roots at lower culm nodes. It has ovate, elongate, sharply pointed leaf blades 4-8 cm long x 1.5-2 mm wide that are arranged alternately. Scattered 1-2 mm hairs are present on the upper and lower leaf blade surfaces and the blades are horizontally rippled or undulating. The sheaths and culm axis are noticeably pilose with hairs 1-4 mm long. It has delicate stolons, 1-3 mm in diameter that sometimes creep beneath leaf litter, rooting and branching from nodes. O. hirtellus subsp. undulatifolius has an inflorescence about 10 cm long, comprising a raceme of sparsely placed clusters of spikelets, each 3.5 mm long, with sticky awns 6-12 mm long (extended pointed tips). The spikelets secrete a sticky substance, ideal for dispersal via adhering to passing animals, clothing and footwear (Scholz, 1981; Peterson et al., 1999; Kyde and Marose, 2008; Westbrooks and Imlay, 2009; Noltie, 2000; ISSG, 2012).

O. hirtellus subsp. undulatifolius has been described as looking like small bamboo. Distinguishing characteristics include a 3-veined first glume, a 5-veined second glume and a 7-veined lemma (ISSG, 2012).

With classification and multiple synonyms found in the literature, consideration should be given to the description of Oplismenus undulatifolius, a perennial with culms 20-50 cm tall, straggling, ascending from a prostrate base. Leaf sheaths are usually densely tuberculate-hairy, sometimes glabrous; ligules about 1 mm long; blades 1-15 cm long, 0.3-3 cm wide, glabrous or hairy, lanceolate to narrowly ovate, base somewhat rounded to oblique, tip acute. Panicles are 9-15 cm long, glabrous or hispdulous; branches 4-9, up to 2 cm long, axes often setose, spikelets in 3-5 pairs. Spikelets are lanceolate, hispidulous. Lower glumes are 3-5-veined, awned, awn 5-10 (15) mm long; upper glumes 5-veined, awned, awn 2-5 mm long; lower lemmas herbaceous, 5-9-veined, mucronate, mucro 1-2 mm long; upper lemmas subcoriaceous, smooth (Wipff, 2009). The Flora of North America treats undulatifolius as a "subspecies of O. hirtellus in accordance with the treatment by Scholz (1981) but recognizes that the subspecies differs in its shorter panicle branches, and its hairiness. It is treated as a species in Australia and China (Wipff, 2009).

Distribution

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O. hirtellus subsp. undulatifolius is a cosmopolitan grass species that is found in temperate, subtropical and tropical areas of the world (Hitchcock, 1920; Scholz and Byfeld, 2000; Valdés et al., 2009; Chen and Phillips, 2012; USDA-APHIS PPQ PERAL, 2012; USDA-ARS, 2012). 

Distribution Table

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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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AzerbaijanPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
BhutanPresentNativeNoltie, 2000
ChinaPresentNative Not invasive Scholz, 1981
-AnhuiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-FujianWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-GuangdongWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-GuangxiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-GuizhouWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-HebeiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-HenanWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-HubeiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-HunanWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-JiangsuWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-JiangxiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-ShaanxiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-ShandongWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-ShanxiWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-SichuanWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
-YunnanWidespreadNative Not invasive Chen and Phillips, 2012
-ZhejiangWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
Georgia (Republic of)PresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
IndiaPresentNative Invasive Scholz, 1981O. hirtellus subsp. undulatifolius
-Himachal PradeshPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
-Indian PunjabPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
-Jammu and KashmirPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
-MeghalayaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
-Uttar PradeshPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
IranPresentScholz, 1981O. hirtellus subsp. undulatifolius
JapanPresentScholz, 1981O. hirtellus subsp. undulatifolius
Korea, Republic ofPresentScholz, 1981O. hirtellus subsp. undulatifolius
NepalPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
PakistanPresenteFloras, 2012O. undulatifolius
Sri LankaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
TaiwanWidespreadNative Not invasive Chen and Phillips, 2012O. undulatifolius var. undulatifolius
ThailandPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
TurkeyPresentScholz, 1981O. hirtellus subsp. undulatifolius

Africa

BotswanaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
EthiopiaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
KenyaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
MadagascarPresentUSDA-APHIS, 2012O. hirtellus subsp. undulatifolius
MaliPresentUSDA-APHIS, 2012O. hirtellus subsp. undulatifolius
MozambiquePresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
South AfricaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
SwazilandPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
TanzaniaPresentGBIF, 2012; USDA-ARS, 2012O. hirtellus subsp. undulatifolius
ZambiaPresentUSDA-ARS, 2012O. hirtellus subp. undulatifolius
ZimbabwePresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius

North America

USAPresentPresent based on regional distribution.
-HawaiiPresent, few occurrencesIntroduced Invasive Snow and Lau, 2010O. hirtellus subsp. undulatifolius present in Hawaii for over 150 years
-MarylandWidespreadIntroduced Invasive Peterson et al., 1999O. hirtellus subsp. undulatifolius
-VirginiaPresent, few occurrencesIntroduced Invasive Westbrooks and Imlay, 2009; ISSG, 2012

Europe

CroatiaPresentValdes et al., 2009; USDA-ARS, 2012O. hirtellus subsp. undulatifolius
ItalyPresentScholz, 1981; Valdes et al., 2009O. hirtellus subsp. undulatifolius
Russian FederationPresentScholz, 1981; Valdes et al., 2009O. hirtellus subsp. undulatifolius
SloveniaPresentDakskobler and Vres, 2009; Valdes et al., 2009; USDA-ARS, 2012O. hirtellus subsp. undulatifolius
SpainPresentValdes et al., 2009; USDA-ARS, 2012O. hirtellus subsp. undulatifolius
SwitzerlandPresentScholz, 1981; Valdes et al., 2009O. hirtellus subsp. undulatifolius
Yugoslavia (former)PresentScholz, 1981O. hirtellus subsp. undulatifolius

Oceania

AustraliaPresentPresent based on regional distribution.
-New South WalesPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
-QueenslandPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius
Papua New GuineaPresentUSDA-ARS, 2012O. hirtellus subsp. undulatifolius

History of Introduction and Spread

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In 1996 Ed Uebel discovered O. hirtellus subsp. undulatifolius in Patapsco Valley State Park and at Liberty Reservoir in Maryland (Kerrie Kyde, MD DNR, personal communication). The introduction and establishment of the subspecies in Hawaii is based on a review and assessment for the Records of the Hawaii Biological Survey for 2008 (Snow and Lau, 2008).

The sterile variegated garden species, Oplismenus (Panicum) X variegatum, has been in the horticultural trade since the mid nineteenth century (Long, 1874).

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Hawaii mid-19th C  Yes Snow and Lau (2010)
Maryland 1990s Yes Kyde and Marose (2008); Westbrooks and Imlay (2009) Several theories as to mode of introduction; dispersal by animal and human traffic, water

Risk of Introduction

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USDA-APHIS PPQ estimates that about 30% of the United States is suitable for the establishment of O. hirtellus subsp. undulatifolius (USDA-APHIS PPQ PERAL, 2012). Because it is already established in the United States a risk assessment was not deemed necessary.

Habitat

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O. hirtellus subsp. undulatifolius grows in moist, lightly shaded areas in forests. It is native in warm-temperate and subtropical regions of Asia, India and Africa and has become an invasive weed in the eastern United States as well as reported invasive in Hawaii (Kyde and Marose, 2008; Snow and Lau, 2008; Wipff, 2009; USDA-APHIS PPQ PERAL, 2012).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
Terrestrial – ManagedManaged forests, plantations and orchards Secondary/tolerated habitat Harmful (pest or invasive)
Disturbed areas Principal habitat Harmful (pest or invasive)
Terrestrial ‑ Natural / Semi-naturalNatural forests Principal habitat Harmful (pest or invasive)
Natural forests Principal habitat Natural
Riverbanks Secondary/tolerated habitat Harmful (pest or invasive)

Hosts/Species Affected

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Evidence suggests that O. hirtellus subsp. undulatifolius, a shade tolerant perennial grass, poses a threat to forest ecosystems. It may crowd out native herbaceous plants, and seems to prevent regeneration of native hardwood tree species (ISSG, 2012). Westbrooks and Imlay (2009) report that O. hirtellus subsp. undulatifolius has "displaced native species in several locations of both Maryland and Virginia and may alter environments". As of this date more work is needed to identify how this species interacts with both native and exotic species in forest understore communities (Beauchamp, 2012).

Growth Stages

Top of page Pre-emergence, Seedling stage, Vegetative growing stage

Biology and Ecology

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Genetics

Standard treatments suggest 2n = 54 though there is some suggestion of variability, which is specimen dependent (USDA-APHIS PPQ CPHST, 2009; Chen and Phillips, 2012).

Reproductive Biology

O. hirtellus subsp. undulatifolius produces racemes with 3-7 spikelets from August to November in North America. Its seeds can hold dormancy due to an impermeable membrane that must be scarified before a sufficient number of seeds can germinate. The seed coat may be breached after passing through the digestive system of animals, from insect activity, freezing temperatures, wind, rain, animal traffic or microbial activity in the soil. Seeds are somewhat freeze tolerant and may be viable in the soil seed bank for at least two years or more (USDA-APHIS PPQ CPHST, 2009).

Reproduction in most Oplismenus species is likely apomictic; florets have both male and female parts (Scholz, 1981). Oplismenus subsp. undulatifolius are wind or self pollinated. USDA-APHIS research produced abundant fertile seeds of O. hirtellus subsp. undulatifolius from greenhouse grown plants that have little to no exposure to pollinators or wind (USDA-APHIS PPQ CPHST, 2009; USDA-APHIS PPQ PERAL, 2012).

O. hirtellus subsp. undulatifolius also produces and can spread by stolons and may produce dense monocultural stand or colonies (Kyde and Marose, 2008; Thompson, 2009). 

Physiology and Phenology

The species has relatively showy flowers for a grass and blooms in late August to November.

Environmental Requirements

O. hirtellus subsp. undulatifolius is most abundant in forest interiors with deep litter. It requires moist places and is suited to light shade in forests as it is non-tolerant of bright sunlight (Kyde and Marose, 2008; Wavyleaf Basketgrass Task Force, 2009; Westbrooks and Imlay, 2009; Beauchamp, 2012). O. hirtellus subsp. undulatifolius is found in temperate environments of coastal plain, piedmont, and montane regions. The grass thrives in full canopy hardwood forests, forest margins, and shady riparian zones and appears adaptable to a wide range of pH (Imlay, Kyde and Westbrooks, USA, personal communication, 2009). 

Climate

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ClimateStatusDescriptionRemark
Af - Tropical rainforest climate Tolerated > 60mm precipitation per month
As - Tropical savanna climate with dry summer Tolerated < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Tolerated < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Tolerated Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Tolerated Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)

Notes on Natural Enemies

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None known.

Means of Movement and Dispersal

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Seeds of O. hirtellus subsp. undulatifolius are "wrapped [attached to] in a viscid awn that aids in its epizoochoric dispersal" (USDA-APHIS PPQ PERAL, 2012). Spikelets of O. hirtellus subsp. undulatifolius have very long awns (extended pointed tips) which secrete a sticky substance; a specialized mechanism for dispersal that works by adhering to passing animals, fur, feathers, clothing and footwear (ISSG, 2012; USDA-APHIS PPQ PERAL, 2012).

There is a moderate to high degree of uncertainty based on the limited amount of research as to the modes of dispersal.

Natural Dispersal (Non-Biotic)

Non-biotic (wind, water) mechanisms of dispersal for O. hirtellus subsp. undulatifolius are not evident (USDA-APHIS PPQ PERAL, 2012).

Vector Transmission (Biotic)

There is on-going research into biotic modes of dispersal including but not limited to sticking to ground foraging birds, small rodents and deer. The extremely sticky nature of the awns permits reasonable speculation that there is considerable biotic involvement in the dispersal of O. hirtellus subsp. undulatifolius (USDA-APHIS PPQ PERAL, 2012).

Accidental Introduction

O. hirtellus subsp. undulatifolius seeds readily adhere to human hair, skin, and wool (Scholz, 1981). O. hirtellus subsp. undulatifolius can stick to timber and be transported during months when fruit is ripe according to personal communication from Kyde (2010) to USDA-APHIS (USDA-APHIS PPQ PERAL, 2012).

Intentional Introduction 

There is no evidence of intentional introduction of O. hirtellus subsp. undulatifolius.

Impact Summary

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CategoryImpact
Cultural/amenity Negative
Environment (generally) Negative

Economic Impact

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The recent nature of the introduction and spread makes it hard to ascertain an economic impact. USDA-APHIS PPQ PERAL (2012) reports homeowner control efforts for the removal of O. hirtellus subsp. undulatifolius from lawns in Virginia, USA.

Environmental Impact

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Impact on Habitats

O. hirtellus subsp. undulatifolius forms a dense carpet layer in the forest understory and has been found to grow underneath Japanese stilt grass, creating either a new canopy layer where stiltgrass does not occur or an additional layer where stiltgrass does occur (Kyde and Marose, 2008; Beauchamp, 2012; USDA-APHIS PPQ PERAL, 2012). Westbrooks and Imlay (2009) claim that "once it becomes established, [O. hirtellus subsp. undulatifolius] spreads rapidly through wooded natural areas, crowding out native herbaceous plants and preventing regeneration of native hardwood tree species."  

Impact on Biodiversity

O. hirtellus subsp. undulatifolius displaces native plants in Maryland and Virginia, USA (Kyde and Marose, 2008; Wavyleaf Basketgrass Task Force, 2009; Westbrooks and Imlay, 2009).

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Tolerant of shade
  • Highly mobile locally
  • Fast growing
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
  • Reproduces asexually
Impact outcomes
  • Altered trophic level
  • Changed gene pool/ selective loss of genotypes
  • Damaged ecosystem services
  • Ecosystem change/ habitat alteration
  • Modification of successional patterns
  • Monoculture formation
  • Reduced native biodiversity
  • Threat to/ loss of endangered species
  • Threat to/ loss of native species
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - shading
  • Competition - smothering
  • Rapid growth
  • Rooting
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect as a commodity contaminant
  • Difficult to identify/detect in the field
  • Difficult/costly to control

Uses

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Economic value

None. The related species O. hirtellus may have some use as a forage crop (Dalziel and Hutchinson, 1948).  

Social benefit

None. The website Plants for Use (2008) mentions that because of the sticky nature of the inflorescence, O. hirtellus may be used to catch rats. The exact mechanism for capturing the rats via sticky inflorescences is not reported however.

Similarities to Other Species/Conditions

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O. hirtellus subsp. setarius and O. hirtellus subsp. fasciculatus are native North American subspecies of O. hirtellus and have been confused with the invasive O. hirtellus subsp. undulatifolius. Differentiation is confirmed by genetic analysis (Scholz, 1981; Wipff, 2009; USDA-APHIS PPQ CPHST, 2009; Weakley, 2011).   

In USA, subsp. undulatifolius is distinguished from the native subspecies of O. hirtellus by: panicles branches up to 2 cm long; sheaths and culms noticeably pilose, hairs 1-3 mm long; lemmas 7-veined (in ssp. undulatifolius) and panicle branches often 2-3 cm long; sheaths and culms glabrous or with a few, scattered hairs less than 1 mm long; lemmas (7) 9-11-veined in O. hirtellus (Grass Manual, 2013).

Arthraxon hispidus, small carpgrass stands 0.5 m tall with oval to lance-shaped leaves. Leaves are 2.5-7.6 cm long, 0.5 cm wide and have heart shaped bases. The margins of the leaves have conspicuous hairs. Flowers bloom in early fall and are contained in one to several 2.5-7.6 cm long spikes. Small carpgrass inhabits wet areas such as stream banks, flood plains and shoreline of eastern and central United States. Although similar to O. hirtellus subsp. undulatifolius, it does not have the same wavy leaves (Weakley, 2011; ISSG, 2012). 

Another similar species is Microstegium vimineum, commonly known as Japanese stilt grass. This annual can reach a similar height to O. hirtellus subsp. undulatifolius, standing at 1 m tall but it has pale green lance shaped leaves and smooth stems. Japanese stiltgrass is also noticeably different as it has a reflective silver stripe down the middle of its leaves (ISSG, 2012).

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

Early Detection and Rapid Response (EDRR) through interagency partnering and the work of volunteers is the best strategy for addressing the problem of establishment and spread of O. hirtellus subsp. undulatifolius (Westbrooks and Imlay, 2009).   

Physical/Mechanical Control

In sites where O. hirtellus subsp. undulatifolius is established with indigenous species, manual removal of individual plants is the optimum method of control. PCA-APWG states: "Plants can be pulled by hand fairly easily anytime except when in bloom. If not in flower, pulled material can be left on-site to desiccate and disintegrate. If plants are flowering and the possibility of seeds exists, it is best to bag and remove pulled material. However, once the awns become sticky it is probably best to stop pulling or working in basketgrass infestation because of the likelihood of spreading seeds" (PCA-APWG, 2010).

Movement Control

When O. hirtellus subsp. undulatifolius is in bloom, extreme caution must be taken to avoid physically entering communities of the species because of the extreme stickiness of the spikelets and the likely spread of the plant to new areas (Mark Imlay, USA, personal communication, 2012).

Chemical Control

Herbicide trials in Maryland, USA on chemical control of O. hirtellus subsp. undulatifolius using clethodim and glyphosate were effective. Both work well but clethodim is recommended as it is grass-specific and so it leaves behind the woodland wildflowers and the sedges (PCA-APWG, 2010). Current populations in Maryland and Virginia are still relatively small and eradication is still possible. Glyphosate has been found to work best late in the year, while grass inhibitors are more effective early in the season (ISSG, 2012). 

Gaps in Knowledge/Research Needs

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The genus Oplismenus needs to be revisited with a focus on a phylogenetic circumscription. O. hirtellus subsp. undulatifolius research is needed in all aspects of this plant from biological and ecological interactions to bioeconomic impacts.   

References

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Atlas of Living Australia, 2012. Oplismenus undulatifolius. Copenhagen, Denmark: GBIF. www.ala.org.au/

Beauchamp VB, 2012. Niche requirements and competitive effects of a new forest invader, Oplismenus hirtellus spp. undulatifolius (wavyleaf basket grass). Maryland, USA: Entomological Society of America. In 997th ESA Annual Meeting (August 5-10, 2012) program annoucement and abstracts

Chen S; Phillips SM, 2012. Flora of China, 22. Cambridge, USA: Harvard University Herbaria, 593-598.

Dakskobler I; Vres B, 2009. Novelities in the flora of the northern part of the Submediterranean region of Slovenija (Novosti v flori severnega dela submediteranskega obmocja Slovenije), 24:13-34.

Dalziel JM; Hutchinson J, 1948. The useful plants of west tropical Africa: being an appendix to the Flora of west tropical Africa. London, UK: Crown Agents for the Colonies, 612.

Davey JC; Clayton WD, 1978. Some multiple discriminant function studies on Oplismenus (Gramineae), 33(1):147-157.

Delfeld M; Delfeld N, 2008. Plants for use. USA, http://plantsforuse.com/

eFloras, 2012. Flora of Pakistan. Missouri, USA: Missouri Botanical Garden. http://www.efloras.org

GBIF, 2012. Global Biodiversity Information Facility. Global Biodiversity Information Facility (GBIF). http://data.gbif.org

Hitchcock AS, 1920. Revisions of North American grasses: Isachne, Oplismenus, Echinochloa, and Chaetochloa. Washington DC, USA: United States Government Printing Office, 93.

Hitchcook AS, 1935. Manual of the grasses of the United States. U.S. Dep. Agric., 1040 pp.

ISSG, 2012. Global Invasive Species Database (GISD). Auckland, New Zealand: University of Auckland. http://www.issg.org/database

Kyde KL; Marose BH, 2008. Wavyleaf basketgrass in Maryland: an early detection rapid response program in progress. Maryland, USA: Maryland Department of Natural Resources. http://www.state.us/wildlife/Plants_Wildlife/WLBG/pdfs/wlbg_poster011108

Long EA, 1874. The home florist: a treatise on the cultivation, management and adaptability of flowering and ornamental plants, designed for the use of amateur florists. Buffalo, NY, USA: Long Brothers.

Noltie HJ, 2000. Flora of Bhutan, Volume 3, Part 2. The Grasses of Bhutan. Edinburgh, UK: Royal Botanic Gardens, 457-883.

Palisot Beauvois AMFJ de, 1812. Essai d'une Nouvelle Agrostographie (Essai d'une Nouvelle Agrostographie). Paris, France: Chez l'Auteur, 54, 168.

Peterson PM; Terrell EE; Uebel EC; Davis CA; Scholz H; Soreng RJ, 1999. Oplismenus hirtellus subspecies undulatifolius, a new record for North America, 64(2):201-202.

Plant Conservation Alliance - Alien Plant Working Group, 2010. Wavyleaf Basketgrass Oplismenus hirtellus ssp. undulatifolius. Washington DC, USA: Plant Conservation Alliance. http://www.nps.gov/plants/index.htm

Scholz H; Byfeld AJ, 2000. Three Grasses New to Turkey, 24:263-267.

Scholz U, 1981. Monographie der Gattung Oplismenus Gramineae, 13:213.

Snow N; Lau A, 2010. Notes on grasses (Poaceae) in Hawai'i: 2 in Records of the Hawaii Biological Survey for 2008, 107:46-60.

The Plant List, 2010. The Plant List Version 1. UK: Royal Botanic Gardens, Kew and Missouri Botanical Gardens. http://www.theplantlist.org/

Thompson JP, 2009. Invasive species: wavyleaf basketgrass - Oplismenus hirtellus subsp. undulatifolius. http://ipetrus.blogspot.com/2009/04/invasive-species-wavyleaf-basketgrass. Blogger. http://ipetrus.blogspot.com/2009/04/invasive-species-wavyleaf-basketgrass.html

USDA-APHIS PPQ CPHST, 2009. Differences of Oplismenus hirtellus ssp. undulatifolius to native and horticultural taxa. Washington DC, USA: USDA.

USDA-APHIS PPQ PERAL, 2012. Weed Risk Assessment for Oplismenus hirtellus (L. Beauv. subsp. undulatifolius (Ard.) U. Scholz (Poaceae) - Wavyleaf basketgrass. Washington DC, USA: USDA.

USDA-ARS, 2012. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

Valdes B; Scholz H; Raab-Straube; Parolly EG von, 2009. Poaceae (pro parte majore). Berlin, Germany: Euro+Med Plantbase. http://www.emplantbase.org/

Wavyleaf Basketgrass Task Force, 2009. Wavyleaf Basketgrass Task Force Meeting Minutes. Washington DC, USA: US Forest Service.

Weakley AS, 2011. Flora of the Southern and Mid-Atlantic States. North Carolina, USA: University of North Carolina Herbarium.

Westbrooks R; Imlay M, 2009. Wavyleaf Basketgrass - A New Invader of Deciduous Forests in Maryland and Virginia. Georgia, USA: Southeast Exotic Pest Plant Council.

Wipff JK, 2009. Grass Manual on the Web: Flora of North America - Oplismenus P. Beauv [ed. by Barkworth M. E.]. Utah, USA: Utah State University. http://herbarium.usu.edu/webmanual/

Organizations

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Denmark: GBIF Global Biodiversity Information Facility, Universitetsparken 15, DK-2100 Copenhagen Ø, http://www.gbif.org/

France: EPPO, European and Mediterranean Plant Protection Organization, 21 boulevard Richard Lenoir, 75011 Paris, http://www.eppo.int/

USA: GISIN, Global Invasive Species Information Network, USGS 12201 Sunrise Valley Drive, Mail Stop 302, Reston, VA, http://ibis-test.nrel.colostate.edu/DH.php?WC=/WS/GISIN/home.html&WebSiteID=4

USA: Intermountain Herbarium, Utah State, 5305 Old Main Hill, Utah State University, Logan, Utah 84322-5305, http://herbarium.usu.edu/

USA: Tropicos, Missouri Botanical Garden - 4344 Shaw Boulevard, Saint Louis, Missouri 63110, http://www.tropicos.org/

USA: USDA-ARS NISIC, National Agricultural Library, Abraham Lincoln Building, 10301 Baltimore Avenue, Beltsville, MD 20705-2351, http://www.invasivespeciesinfo.gov/index.shtml

New Zealand: ISSG Invasive Species Specialist Group, University of Auckland (New Zealand), School of Biological Sciences, Centre for Biosecurity and Biodiversity, http://www.issg.org/

Contributors

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22/08/12 Original text by:

John Peter Thompson, PO Box 1664, Upper Marlborough, Maryland 20773, USA

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