Achnatherum hymenoides (Roemer & J.A. Schultes) Barkworth
 
 
 

 Indian ricegrass, sand grass
 
Prepared by: Jay Cory
 
 
 
 
 
   
  Taxonomy
  Synonymy: Oryzopsis hymenoides (Roem. and Schult.) Ricker., Stipa hymenoides Roemer & J.A. Schultes, Eriocoma cuspidata Nutt.
Latin name meaning: Oryzopsis is derived from the Greek word oruzu, rice, and opsis, appearance (22,23)
Family: Poaceae
Common name: Indian ricegrass, sand grass
Similar species: White grained mountain-rice grass (Oryzopsis asperifolia) and short-awn rice grass (Oryzopsis pungens).
   
  Key Identification Characteristics
  Growth form: Indian ricegrass is a perennial grass that grows in dense clumps. Plants eventually become doughnut shaped because the centers of plant die (16). Plants are 3-7dm tall.
Roots: Roots are fibrous, deep (150 cm)(21) and they may have a rhizosheath formed by sand grains encasing the roots of the grass. Rhizosheaths are important because nitrogen fixation is associated with them, along with water retention and uptake (2, 26, 28). Root hairs hold sand grains in place, along with cementing agents secreted by the plant (2). Indian ricegrass can adjust to shifting sands by elongating basal internodes and producing adventitious roots at these nodes (20). Leaves: Leaves are slender (5mm) and nearly as long as the stems; margins are typically rolled inward
Sheaths: Leaf sheaths are round, split, prominently veined, usually with a fringe of hairs at throat. The base of leaf sheaths is often purple.
Ligules: Ligues are membranous, to 8 mm long, pointed, and conspicuous.
Inflorescence: The inflorescence is a loose panicles, 10-20 cm long, with panicle branches in pairs, spreading and flexible. Glumes are ovate-long-pointed, thin, papery with 3 or 5 greenish nerves, 6-7 mm long, and hairless to finely hairy. Lemmas are 3-4 mm long, densely long soft-hairy with white hairs, turning blackish at maturity. Awns are 4-6 mm long and deciduous.
   
  Ecological & Physiological Relations
  Life history: Indian ricegrass is a short-lived perennial; growth usually declines by the fifth year with a maximum age of 30 years (24)
Native/Introduced: Indian ricegrass is a native grass to North America
Photosynthetic pathway: C3
Distribution: Indian ricegrass grows from Alberta, Arizona, British Columbia, California, Colorado, Idaho, Kansas, Manitoba, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, Saskatchewan, South Dakota, Texas, Utah, Washington, Wyoming and into Mexico(9, 31, 34). Indian ricegrass is one of the most drought-enduring, native grasses in North America (22). Indian ricegrass usually grows on well-aerated rocky or sandy soils such as sand dunes, dry exposed river banks, eroded slopes, and sandy grasslands (9, 22, 23, 31, 34)
Succession: Indian ricegrass is often associated with primary succession on disturbed sandy soils (9, 21, 22, 23, 31). It grows from seeds in caches made by rodents, and is often seeded by humans to stop wind erosion of sandy soils (7, 9, 10, 11, 19, 31,). It is often the dominant perennial grass on salt desert ranges of western North America (29).
Canopy/ground cover, LAI, height: Indian ricegrass is an important native species for revegetation of unstable sandy dry soil (7, 10, 11, 32), and can reach a height of 7 dm (23) under good growing conditions.
Competitive ability as seedlings, in mixes, invasive: Indian ricegrass is well adapted to desert environments, it flowers prolifically, and sets seed quickly; vernalization is not required for flowering (20). Germination of seeds is low unless scarified, aged, or stratified (5, 9, 12, 29, 30, 32). In very sandy and dry environments Indian ricegrass may be the only plant to emerge (26).
   
  Management Considerations
  Grazing: Indian ricegrass is palatable for most grazing animals, and can sustain relatively high grazing pressure if it is allowed to produce enough seed for reproduction. Indian ricegrass is a decreaser under grazing and has disappeared as a prominent species in some areas because of improper grazing management (23). It is preferred by livestock and cures well for winter fe (3, 23, 31, 34). Indian ricegrass decreases under grazing because grazing removes the seeds, and therefore plants are not replaced. Indian ricegrass is a short-lived perennial and therefore death is the result of age, because grazing has no significant effect on its longevity (1). Long-term, heavy grazing has little effect on root and crown biomass, and it does not affect the non-structural carbohydrate reserves, or the seasonal cycle of reserves of this grass (15). Heavy grazing eliminates or greatly reduces non-resistant genotypes. Indian ricegrass has a high regrowth capacity rather than defense mechanisms to overcome intense herbivory (13, 15).
Burning: Because Indian ricegrass establishes from seed, it will usually re-colonize a burnt area within 2-4 years by seeds brought in from surrounding un-burnt areas or from seed buried in the soil (34)
Restoration: Indian ricegrass is adapted for revegetation on sandy, arid areas in the western U.S. and Canada (5). It is has been used for re-vegetating coal and oil shale, as well as uranium mine tailings (26, 32). Germination of this grass is often low and the seed very expensive. Much research has been conducted into increasing germination and decreasing seed shattering.
Increasing germination: Under natural conditions rodents collect bury seeds for winter food; seeds that are not consumed germinate from these caches (10). Rodents may find the seeds and eat many of them before they can germinate. The lemma and palea of the caryopsis limit oxygen transfer to the embryo, along with embryo dormancy decrease germination (5, 11, 19, 29). Germination of seeds with the lemma and palea removed is much higher than for complete seeds (12, 29, 30). Mechanical or acid scarification can increase germination (5, 12, 17, 19, 29, 30). Scarification may make the seed more susceptible to diseases (12, 17, 29, 30). Older seeds with lower vigor may respond negatively to scarification. Aging seeds and pre-chilling can also increase germination (5, 9, 32).
Seeding: Indian ricegrass seeds can germinate from a depth of 15 cm, but best emergence occurs when seeds are planted at a 5 cm depth (31). Greatest germination occurs at low seeding rate (0.3 kg/ha) perhaps because of decreased intraspecific competition or because it was harder for predators find seeds. Seeds planted in fall germinate best probably because of chilling during the winter and seed aging (9, 31). Commercial varieties available include Poloma, Nezpar, and Rim Rock.
   
  References
 
  1. Alzerreca-Angelo, H., E.W. Schupp and S.G. Kitchen. 1998. Sheep grazing and plant cover dynamics of a shadscale community. J. Range Manage. 51:214-222.
  2. Bristow, C.E., G.S. Campbell, L.H. Wullstein and R. Neilson. 1985. Water uptake and storage by rhizosheaths of Oryzopsis hymenoides: A numerical simulation. Physiol Plant. 65:228-232.
  3. Cook, C.W., K. Taylor and L.E. Harris. 1962. The effect of range condition and intensity of grazing upon daily intake and nutritive value of the diet on desert ranges. J. Range Manage. 15:1-6.
  4. Everett, R.L., P.T. Tueller, J.B. Davis and A.B. Bnmner. 1980. Plant phenology in galleta-shadscale and galleta-sagebrush associations. J. Range Manage. 33:446-450.
  5. Griffith, L.W. and D.T. Booth. 1988. Indian ricegrass seed damage and germination responses to mechanical treatments. J. Range Manage. 41:335-337.
  6. Jones, T.A. and D.C. Nielson. 1989. Self-compatibility in "Paloma" Indian ricegrass. J. Range Manage. 42:187-190.
  7. Jones, T.A. 1990. A viewpoint on Indian ricegrass research: its present status and future prospects.J. Range Manage. 43:416-420.
  8. Jones, T.A. and D.C. Nielson. 1992. High seed retention of Indian ricegrass. J. Range Manage. 45:72-74
  9. Jones, T.A. and D.C. Nielson. 1992. Germination of prechilled mechanically scarified and unscarified Indian ricegrass seed. J. Range Manage. 45:175-179
  10. McAdoo, J.K., C.C. Evans, B.A. Roundy, J.A. Young and R.A. Evans. 1983.
    Influence of heteromyid rodents on Oryzopsis hymenoides germination Seed collecting and caching activities, on sandy desert rangelands, Nevada. J. Range Manage. 36:61-64
  11. McDonald, M.B. Jr. and A.A. Khan. 1977. Factors determining germination of Indian ricegrass seeds. Agron. J. 64:558-563.
  12. McDonald, M.B.,Jr. and A.A. Khan. 1983. Acid scarification and protein synthesis during seed germination Oryzopsis hymenoides, gibberellin, abscisic acid. Agron J. 75:111-114.
  13. Meijen, E. vander, M. Wijn and HJ. Verkaar. 1988. Defense and regrowth, alternate plant strategies in the struggle against herbivores. Oikos 51:355-363.
  14. Orodho, A.B., R.L. Cuany and M.J. Trlica. 1998. Previous grazing or clipping affects seed of Indian ricegrass. J. Range Manage. 57:37-41.
  15. Orodho, A.B. and M.J. Trlica. 1990. Clipping and long-term grazing effects on biomass and carbohydrate reserves Indian ricegrass. J. Range Manage. 42:53-57.
  16. Pearson, L.C. 1979. Effects of temperature and moisture on phenology and productivity of Indian ricegrass. J. Range Manage. 32: 127-I 34.
  17. Plummer, A.P. and N.C. Frischknecht. 1952. Increasing field stands of Indian ricegrass. Agron. J. 44:285-287.
  18. Reynolds, T.D. and L. Jr. Fralley. 1989. Root profiles of some native and exotic plant species in southeastern Idaho. Environ Exp. Bot. 29:241-248.
  19. Rogler, G.A. 1960. Relation of seed dormancy of Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] to age and treatment. Agron. J. 52:470-473.
  20. Stoddart, L.A. and J.J. Wilkinson. 1938 Inducing germination in Oryzopsis hymenoides for range reseeding. J. Amer. Soc. Agron. 30:763-768.
  21. Tannas, K. 1997. Common plants of the Western Rangelands. Vol. 1. Curriculum and Instructional Development Services, Lethbridge Community College. Ronald's Printing, Calgary, AB.
  22. United States Department of Agriculture. reprinted 1988. Range plant handbook. Dover ed. Mineola, N.Y.
  23. Ward, A.L. 1971. In vitro digestibility of elk winter forage in southern Wyoming. J. Wildl. Manage. 35:681-688.
  24. West, N.E. 1979. Survival patterns of major perennials in salt desert shrub communities of southwestern Utah. J. Range Manage. 32:442-445.
  25. Whalley, R.D.B., T.A. Jones, D.C. Nielson and R.J. Mueller. 1990. Seed abscission and retention in Indian ricegrass. J. Range Manage. 43:291-294.
  26. Wullstein, L.H. 1980. Nitrogen fixation (acetylene reduction) associated with rhizosheaths of Indian ricegrass (Oryzopsis hymenoides) used in stabilization of the Slick Rock, Colorado tailings pile. J. Range Manage. 33:204-206.
  27. Wullstein, L.H. 1991. Variation in N2 fixation (C2H2 reduction) associated with rhizosheaths of Indian ricegrass (Stipa hymenoides). Amer. Midl. Natur. 126:76-81.
  28. Wullstein, L.H., M.L. Bruening and W.B. Bollen. 1979. Nitrogen fixation associated with sand grain root sheaths (rhizosheaths) with Bacillus polymyxa-like bacteria of certain xeric grasses Oryzopsis hymenoides, Agropyron dasystachyum, Aristida purpurea. Physiol. Plant. 46:1-4.
  29. Young, J.A. and R.A. Evans. 1984. Germination of seeds of 'Paloma' and 'Nezpar' Indian ricegrass (Oryzopsis hymenoides). J. Range Manage. 37:19-21.
  30. Young, J.A., R.A. Evans and D.A. Easi. 1985. Enhancing germination of Indian ricegrass seeds with sulfuric acid. Agron J. 77:203-206.
  31. Young, J.A., R.R. Blank, W.S. Longland and D.E. Palmquist. 1994. Seeding Indian ricegrass in an arid environment in the Great Basin. J. Range Manage. 47:2-7.
  32. Zemetra, R.S., C. Havstad and R.L.Cuany. 1983. Reducing seed dormancy in Indian ricegrass (Oryzopsis hymenoides) revegetation, western United States and Canada, forage crop. J. Range Manage. 36:239-241.
  33. http://www.mip.berkeley.edu/query_forms/browse_checklist.html. 2000. A synonymized checklist of the vascular flora of the United States, Canada and Greenland. Biota of North America Porgram of the North Carolina Botanical Garden.
  34. http://svinet2.fs.fed.us/database/feis/ [1998,March 12]. Fire Effects Information System [Online] (1996, September). Prescribed Fire and Fire Effects Research Work Unit, Rocky Mountain Research Station (producer).

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