Grasses are one of the most important plants within the grassland ecosystem found in the park. Large expanses of grasslands form where wind-blown sediment and erosion have created a layer of soil several feet thick. One of the most devastating causes of grassland destruction is grazing by livestock. Because grazing is not allowed within the park for over fifty years, the area has returned to a more natural state and is one of the largest recovering grasslands in the Southwest.

Individual grasses sprout almost anywhere they can find soil, even in potholes filled with dirt. Most grasses fit into two basic groups, bunch grass and sod-forming grass. Bunch grass is classic arid adapted grass occurring in scattered clumps. Its spreading growth pattern reduces competition for limited soil nutrients and water. Examples of bunch grass include rice grass and needle-and-thread grass—many native grasses throughout the West are bunch forming. The large rice grass seeds are rich in protein and were an important source of food for American Indians. Needle-and-thread grass has a sharp seed attached to a thin thread-like tail which develops in a spiral fashion. As the thread unwinds, it drives the seed into the ground. Both of these grasses are perennial, becoming dormant during droughts. Rice grass plants have been known to live over 100 years, through wet and dry times.

Sod-forming grass is what most people have in their yards. Galleta and blue grama, sod-forming perennials native to Petrified Forest National Park, usually grow together. Cheat grass was accidentally brought to the United States in the 1800s and is now found throughout the park, along with other non-native grasses.

To visitors unaccustomed to the vast landscapes of the Southwest, Petrified Forest National Park can seem somewhat barren. On closer look, the land is teeming with diverse and fascinating life.

Some of the grasses found in Petrified Forest National Park include:

Poaceae

Achnatherum aridum (M.E. Jones) Schultes) Barkworth Mormon needlegrass

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

Achnatherum speciosum (Trin. & Rupr.) Barkworth desert needlegrass

Agropyron desertorum* (Fischer ex Link) J.A. Schultes desert wheatgrass, fairway

Agrostis stolonifera L. creeping bentgrass, redtop

Andropogon gerardii Vitman big bluestem

Andropogon hallii Hack sand bluestem

Aristida adscensionis L. sixweeks threeawn

Aristida purpurea var. longiseta (Steud.) Vasey Fendler threeawn, purple threeawn

Bothriochloa ischaemum* (L.) Keng yellow bluestem

Bothriochloa saccharoides (Sw.) Rydb. silver bluestem needle grama

Bouteloua aristidoides (Kunth) Griseb. needle grama

Bouteloua barbata Lag. sixweeks grama

Boutelouacurtipendula (Michx.) Torr. var. curtipendulasideoats grama

Bouteloua eriopoda (Torr.) Torr black grama

Bouteloua gracilis (Willd. ex Kunth) Lag ex Griffiths blue grama

Bouteloua hirsuta Lag. hairy grama

Bouteloua rothrockii Vasey Rothrock’s grama

Bouteloua simplex Lag. matted grama

Bromus diandrus* Roth ripgut brome

Bromus hordeaceus ssp. hordeaceus* L. soft brome, soft chess

Bromus inermis* Leyss. smoothe brome, Hungarian brome

Bromusarvensis L. - field brome [Bromus japonicus* Thunb. ex Murr. Japanese brome]

Bromus rubens* L. foxtail brome, red brome

Bromus tectorum* L. cheat grass

Calamovilfa gigantea (Nutt.) Scribn. & Merr. giant sandreed

Cenchrus spinifex Cav. coastal sandbur

Chloris virgata Sw. feather fingergrass

Cynodon dactylon* (L.) Pers. Bermuda grass

Dasyochloa pulchella (Kunth) Willd. low woollygrass, fluffgrass

Distichlis spicata (L.) Greene inland saltgrass, desert saltgrass

Echinochloa crus-galli* (L.) Beauv. barnyardgrass

Elymus elymoides ssp. elymoides (Raf.) Swenzy wildrye, squirreltail

Elymus ×pseudorepens (Scribn. & J.G. Sm.) Barkworth & D.R. Dewey [lanceolatus × trachycaulus] false quackgrass

Enneapogon desvauxii Beauv. nineawn pappusgrass, spike pappusgrass

Eragrostis barrelieri* Daveau Mediterranean lovegrass

Eragrostis intermedia A. S. Hitchc. plains lovegrass

Eragrostis mexicana (Hornem.) Link Mexican lovegrass

Eragrostis pectinacea (Michx.) Nees ex Steud tufted lovegrass

Eragrostis spectabilis (Pursh) Steud. purple lovegrass

Hesperostipa comata var. comata (Trin. & Rupr.) Barkworth needle and thread grass

Hesperostipa neomexicana (Thurb. ex Coult.) Barkworth New Mexico feathergrass

Hordeum jubatum L. foxtail barley

Hordeum murinum ssp. leporinum* (Link) Arcang. leporinum barley, rabbit barley

Hordeum pusillum Nutt. little barley

Leptochloa fusca ssp. fascicularis (Lam.) N. Snow bearded sprangletop

Lolium perenne* L. perennial ryegrass

Schedonoruspratensis (Huds.) P. Beauv. - meadow fescue

Muhlenbergia depauperata Scribn. sixweeks muhly

Muhlenbergia longiligula A. S. Hitchc. longtongue muhly

Muhlenbergia porteri Scribn. ex Beal bush muhly

Muhlenbergia pungens Thurb. sandhill muhly

Muhlenbergia torreyi (Kunth.) Hitchc. ex Bush ring muhly

Munroa squarrosa (Nutt.) Torr. false buffalograss

Panicum capillare L. witchgrass

Panicum hirticaule J. Presl Mexican panicgrass

Panicum obtusum Kunth obtuse panicgrass, vine mesquite

Pascopyrum smithii (Rydb.) A. Love western wheatgrass

Pennisetum glaucum* (L.) R. Br. pearl millet

Phragmites australis (Cav.) Trin. ex Steud. common reed

Piptatherum micranthum (Trin & Rupr.) Backworth smilograss

Pleuraphis jamesii Torr. James’ galleta

Poa arida Vasey plains bluegrass

Poa fendleriana (Steud.) Vasey muttongrass

Poa pratensis L. Kentucky bluegrass

Polypogon monspeliensis* (L.) Desf. annual rabbitsfoot grass

Polypogon viridis* (Gouan) Breistr. beardless rabbitsfoot grass

Puccinellia distans* (L.) Parl. weeping alkaligrass

Puccinellia fasciculata (Torr.) Bickn. saltmarsh alkaligrass, Torrey alkaligrass

Puccinellia nuttalliana (J.A. Schultes) A.S. Hitchc. Nuttall’s alkaligrass

Schedonnardus paniculatus (Nutt.) Trel. tumblegrass

Schizachyriumscoparium (Michx.) Nash var. scopariumNew Mexico little bluestem

Scleropogon brevifolius Phil. burrograss

Setaria viridis* (L.) Beauv. green bristlegrass

Sorghum halepense* (L.) Pers. Johnsongrass, millet

Sporobolus airoides (Torr.) Torr. alkali sacaton

Sporobolus contractus Hitchc. spike dropseed

Sporoboluspyramidatus (Lam.) Hitchc. Madagascar dropseed

Sporobolus cryptandrus (Torr.) Gray sand dropseed

Sporobolus flexuosus (Thurb. ex Vasey) Rydb. mesa dropseed

Sporobolus giganteus Nash giant dropseed

Sporobolus interruptus Vasey black dropseed

Thinopyrum ponticum* (Host.) Nevski. tall wheatgrass

Vulpia octoflora var. hirtella (Piper) Henr. sixweeks fescue