Friday, August 24, 2012

Invasive Species - Example of the Cost of Disinterest - wavyleaf basket grass - Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz

               The best way to control or manage invasive species is to find them early and do something about them quickly before they can get established and spread. This strategy is known as IPM (Integrated Pest Management) in agriculture/horticulture and EDRR (Early Detection & Rapid Response) in ecology. Identification of a novel species is the first step because you cannot control what you do not know. Ignorance is not bliss when it comes to gardens, landscapes and natural areas.
               In the Mid Atlantic region of the eastern United States there is a new invader that is spreading rapidly, wavyleaf basket grass. It is now six years since I first wrote about this species. With the exception of the valiant work of a few people such as Imlay, Kyde, Bergmann, Swearingen, Marose, and a small group of concerned, volunteer weed warriors, we have done nothing, and the plant is spreading perhaps soon to a point of no control because the cost will become too great even as the ecosystem damage sky-rockets to a point of no return. We could have controlled this plant and even eradicated 16 years ago when it was first 'discovered' outside of Baltimore, and we could have done it for a few dollars and some hours if we had practiced the principles of EDRR. We did nothing and it is now in the mountains of western Virginia.                
               A review of the uncertainty surrounding accurate identification of Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz is in order. The genus Oplismenus is not economically important but has been known to western science since the early 19th century. As with many grasses, classification and categorization of the many species in the genus Oplismenus is difficult and confused. Oplismenus hirtellus ssp. 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).

               The most complete descriptions of the various members or taxa of the genus Oplismenus was written by Ursula Scholz in 1981 - in German - so bone up on your foreign language skills (Scholz, 1981). Because o the description difficulties inherent in Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz as a host of synonyms or "other names" which add to the confusion when attempting to research this species on the internet.  

The Maryland and Virginia populations have been positively identified as Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz . 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". This ornamental variegated Oplismenus used in gardens and sold at nurseries is not Oplismenus hirtellus ssp. undulatifolius. It is a 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 19th century (Long, 1874).

               Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz  is native to Europe and Asia. It is a shade tolerant, low-growing, perennial grass, with leaf blades that are flat, dark green, about 0.5” wide and 1.5-4” long, with rippling waves across the grass blades.  The leaf sheaths and stems are noticeably hairy.  O.  hirtellus ssp. undulatifolius has spikelet's that form long sticky awns (Scholz, 1981; Peterson et al., 1999; Kyde & Marose, 2008; Westbrooks & Imlay, 2009).

               Be very careful when planning a control effort because there are two native species:   Oplismenus hirtellus ssp. setarius (Lam.) Mez ex Ekman and O. hirtellus subsp. fasciculatus U. Scholz. Also beware that wavyleaf  basketgrass looks like Arthraxon hispidus (Thunb.) Makino and Microstegium vimineum (Trin.) A. Camus. Microstegium vimineum is the ever present rampant invasive also known as Japanese stilt grass.

      I have just finished a datasheet on wavyleaf basket grass, Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz, for CABI's Invasive Species Compendium   


1         Atlas of Living Australia 2012 Oplismenus undulatifolius (Ard.) Roem. & Schult. Australian node of the Global Biodiversity Information Facility (GBIF).
2         Beauchamp, V. B. 2012 Niche requirements and competitive effects of a new forest invader, Oplismenus hirtellus spp. undulatifolius (wavyleaf basket grass). 997th ESA Annual Meeting (August 5 -- 10, 2012) program annoucement and abstracts.
3         Chen, S. & Hillips, S. M. 2012 Flora of China. Harvard University Herbaria 22, 593–598.
4         Dakskobler, I. & Vreš, B. 2009 Novosti v flori severnega dela submediteranskega območja Slovenije (Novelities in the flora of) the northern part of the Submediterranean region of Slovenija. Hladnikia 24, 13–34.
5         Dalziel, J. M. & Hutchinson, J. 1948 The useful plants of west tropical Africa: being an appendix to the Flora of west tropical Africa. Published under the authority of the Secretary of State for the Colonies by the Crown Agents for the Colonies.
6         Davey, J. C. & Clayton, W. D. 1978 Some multiple discriminant function studies on Oplismenus (Gramineae). Kew Bull. 33, 147 – 157.
7 2012 Flora of Pakistan.
8         Global Biodiversity Information Facility (GBIF) 2012 GBIF Data Portal. GBIF Secretariat.
9         Hitchcock, A. S. 1920 Revisions of North American grasses: Isachne, Oplismenus, Echinochloa, and Chaetochloa. Govt. Print. Off.
10       Hitchcock, A. S. 1935 Manual of Grasses of the United States. Miscellane. Washington, D.C., USA: United States Government Printing Office.
11       ISSG 2012 Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species.
12       Kyde, K. L. & Marose, B. H. 2008 Wavyleaf basketgrass in Maryland: an early detection rapid response program in progress. Invasive Resources,.
13       Long, E. A. 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.
14       Palisot de Beauvois, A. M. F. J. 1812 Essai d’une Nouvelle Agrostographie. Paris, FR:
15       PCA-APWG 2010 Wavyleaf Basketgrass Oplismenus hirtellus ssp. undulatifolius (Ard.) U. Scholz. PCA-APWG.
16       Peterson, P. M., Terrell, E. E., Uebel, E. C., Davis, C. A., Scholz, H. & Soreng, R. J. 1999 Oplismenus hirtellus subspecies undulatifolius, a new record for North America. Castanea 64, 201–202.
17       Plants for Use 2008 Oplismenus hirtellus (L.) Palib. POACEAE Common names: Basket Grass (Hortus).
18       Scholz, H. & Byfeld, A. J. 2000 Three Grasses New to Turkey. Turk J Bot 24, 263–267.
19       Scholz, U. 1981 Monographie der Gattung Oplismenus Gramineae. Phanerogamarum monographiae 13, 213.
20       Snow, N. & Lau, A. 2008 Notes on grasses (Poaceae) in Hawai‘i: 2. Records of the Hawaii Biological Survey, Bishop Museum Occasional Papers 107, 46–60.
21       The Plant List 2010 Version 1.
22       Thompson, J. P. 2009 Invasive species: wavyleaf basketgrass - Oplismenus hirtellus subsp. undulatifolius. Invasive Notes Weblog.
23       USDA ARS 2012 Germplasm Resources Information Network - (GRIN). National Genetic Resources Program.
24       USDA-APHIS PPQ CPHST. 2009 Differences of Oplismenus hirtellus ssp. undulatifolius to native and horticultural taxa. , 33–35.
25       USDA-APHIS PPQ PERAL 2012 Weed Risk Assessment for Oplismenus hirtellus (L.) P. Beauv. subsp. undulatifolius (Ard.) U. Scholz (Poaceae) – Wavyleaf basketgrass - ver 2, June 14, 2012.
26       USDA-ARS 2012 Germplasm Resources Information Network (GRIN).
27       Valdés, B., Scholz, H., Raab-Straube, E. von & Parolly, G. 2009 Poaceae (pro parte majore). Euro+Med Plantbase - the information resource for Euro-Mediterranean plant diversity.
28       Wavyleaf Basketgrass Task Force - 2009 Wavyleaf Basketgrass Task Force Meeting Minutes. , 9.
29       Weakley, A. S. 2011 Flora of the Southern and Mid-Atlantic States. North Carolina Botanical Garden & University of North Carolina at Chapel Hill.
30       Westbrooks, R. & Imlay, M. 2009 Wavyleaf Basketgrass – A New Invader of Deciduous Forests in Maryland and Virginia.
31        Wipff, J. K. 2009 Flora of North America - Oplismenus P. Beauv.- 25.06.  

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