Contents
- Plant communities
- Functional groups
- Field identification of grasses
- Bluebunch wheatgrass
- Crested wheatgrass
- Bottlebrush squirreltail
- Idaho fescue
- Thurber's needlegrass
- Needle-and-thread grass
- Prairie junegrass
- Indian ricegrass
- Basin wildrye
- Sandberg bluegrass
- Cheatgrass
- Medusahead
- Ventenata
- Tips: Seedling identification
- Tips: Plant collection and working with a botanist
- Perennial bunchgrass cheat sheet
- Annual grass cheat sheet
- Table of current and historic synonyms
- Glossary of terms
- Additional resources
Get the full report
Plant communities
As you move across the northern Great Basin, you encounter hundreds of different plant species forming a large variety of plant communities. Plant communities are associations of plant species that are shaped by abiotic and biotic factors such as soils, climate and competition. The resulting communities are often described by listing the two or three most dominant species on a site.
To make informed decisions, land managers in the northern Great Basin must know an area’s plant community and its members. Plants respond to abiotic and biotic conditions around them, and this allows you to infer what has happened on the site and what may develop in the future.
Some plants flourish after disturbances. The presence of these plants in high numbers could be a clue that there has been a recent fire or overgrazing. Other species decline with disturbance, and this may help you predict how a plant community will change when facing drought or disturbance from off-road vehicles. Some species may not be present every year, lying dormant and waiting for the perfect set of conditions to thrive. These plants give you clues to episodic climate events.
This guide provides detailed identification information for common grass species found throughout the northern Great Basin, highlighted in green on the accompanying map. However, many of these grasses are found throughout the Great Basin (highlighted in blue on the map). Several can be found throughout the West.
Under ideal management conditions, you would know the genus and species of every plant on your site, some measure of its vigor (such as percent cover or aboveground biomass), and how it responds to disturbances. However, what do you do when you are new to an area or do not have the time or money to identify each and every plant in the community? What if you are unable to follow a site over several years to get a good feel for its condition? You still can learn from the plants on the ground without a genus-species identification. To do this, identify your site’s plants by functional groups.
Terms to know
Abiotic factor: nonliving things, such as chemical or physical factors, that affect ecosystems and the species in them. Abiotic factors affecting plants can include climate and habitat factors such as sunlight, soil type, water, temperature and many more.
Biotic factor: the living components of an ecosystem, which includes plants, animals, bacteria, fungus and all other living things. Biotic factors affecting plants can include competition with other plants, consumption by herbivores, interactions with fungus and bacteria, and other interactions of living things within an ecosystem.
Functional groups
Functional groups are categories of plants grouped together based on similar growth habits, physical features and roles within the plant community. An example of two simple and readily understood functional groups are annual and perennial plants.
Annual plants live for one year (Figure 1A). They start as a seed, sprout, grow, flower, produce more seed for next year’s generation and then die. The majority of their resources are allocated to seed production to ensure the species’ existence through time. Perennial plants also start from seed and are capable of living multiple years. Perennial plants invest resources into structures that allow them to survive winters, outlast droughts and exist through time, therefore perennials may not produce seed when conditions are poor.
Even without knowing the name of a plant, you can learn much about its role in a community, or its response to disturbance, by understanding whether it employs the annual or perennial strategy.
You can further subdivide annual plants into grasses and forbs (broad-leafed herbaceous plants), and perennial plants into grasses, forbs, shrubs and trees (Figure 1C). Within perennial grasses, you could subdivide them further into rhizomatous or bunch-forming perennial grasses (Figure 1D).
This is the power of the functional group as a management tool. You can create a functional group specific to your needs that helps you track, monitor or answer biological questions about your site. You can define two functional groups based on a perennial shrub’s response to fire (that is, is it killed or does it resprout?). You may also choose to base functional groups on how palatable plants are to a target wildlife species, such as like browsing deer or grazing elk.
Whatever functional groups you choose, they should be biologically based and help answer the management questions you have on your site. Many land managers use Ecological Site Descriptions, also known as ESDs, which provide site information regarding soils, climate and vegetation characteristics and interpretation of that information relative to a site’s management and disturbance history. Ecological site descriptions group plants by functional group, and you may choose to use the same groups as the ecological site descriptions for your site. To learn more about ecological site descriptions and how to use them as a management tool, see An Introduction to Using Ecological Site Descriptions as a Management Tool by Dustin Johnson and Kirk Davies. Access and download ecological site descriptions for your site.
For another example of commonly used functional groups in the sagebrush ecosystem and more background on the ecology in the northern Great Basin, see Western roots: Diving into a sea of diversity (PNW 714).
Functional groups in the field
Like all natural systems, not all plants fit neatly into functional groups. Some plants are biannual, which means that they live for two years only. These are technically perennial, but short-lived. You can group them with the annuals or the perennials, or you can create a new functional group if that serves your needs best. Many invasive weed species fall in the biannual category.
Other plants may have persistent woody bases but behave more like perennial forbs. They could be classified as perennial forbs or as a subshrub functional group created just for them. It is crucial that you define your functional groups in a plant community so that they are useful and help answer specific management questions. Plants that do not cleanly fit into the groups may or may not be important to you, and your decision-making team will need to decide if those “misfits” need more consideration. Figures 2–6 show plant communities in the northern Great Basin and the functional groups within them.
Field identification of grasses
This guide focuses on the most common northern Great Basin species within the perennial bunchgrass functional group. It will touch on a few common examples of the annual grass functional group.
Grasses can be difficult to identify to a species level. Most grass keys and guides use reproductive features to identify species, and seed heads and seeds are only available during a short window each year. If you are trying to identify a grass during the other 10–11 months of the year, vegetative features are helpful.
Identifying grasses using only fall regrowth after a fire (Figure 7A, B), dormant bunchgrasses in the middle of winter (Figure 8A, B) or newly emerged seedlings in a restoration project (Figure 9), requires physical structures that are available year-round. This photo guide will focus on those vegetative features.
Vegetative characteristics of common Great Basin grass species
The individual unit of a grass plant is a tiller (Figure 10). A tiller consists of a single stalk of leaves. A tiller may form a reproductive culm. The seed head is formed at the end of the culm. A leaf sheath is leaf-like material that wraps around younger leaves or, in the case of a reproductive tiller, the culm.
You can imagine the sheath and the collar as a shirt — some shirts button right to the top and are closed around the neck. Other shirts — or even a robe — are loosely wrapped around the neck and left open. Leaf sheaths and collars can be closed, tightly wrapped, or open and loose (Figure 11). Leaf collars are one of the key physical features that you can use to identify northern Great Basin grass species year-round.
A grass leaf blade grows from the bottom up — this is why you can mow your lawn and not kill the grass. The leaf blade grows like a fingernail from the nail bed. The ligule (Figure 11) is an extra piece of tissue that forms at the growth point. You can think of the ligule as a “cuticle” that forms as the leaf blade grows. Ligules take numerous forms. For example, ligules can be smooth or shaggy, pointed or flat, white or see-through, or too small to see without a hand lens. Continuing the fingernail analogy, the auricles are little protrusions, or “hangnails,” at the leaf collar’s edge (Figure 11).
Perennial bunchgrasses
bluebunch wheatgrass
Pseudoroegneria spicata (Pursh) A. Löve ssp. spicata
Old seed heads on bluebunch wheatgrass often persist into the next growing season. They are a long, slender spike that zigzags slightly (Figure 12A). These can be found sticking above the bulk of the bunchgrass. Bluebunch wheatgrass can grow into old, open bunches where the center has died and the new growth has formed a ring. The grass pictured in Figure 12C burned in a fire, and all that remains are the younger tillers on the outside. You can almost picture the original plant that is missing from the middle.
The bluebunch wheatgrass collar is often a well-defined “purple” rust color with long, curled auricles (Figure 13). The ligule for bluebunch wheatgrass is not noticeable without a hand lens. Bluebunch wheatgrass’ leaf blades are not much wider than the culm. The well-defined auricles and narrow leaf blades can even be seen in winter on dead material.
crested wheatgrass
Agropyron cristatum (L.) Gaertn
Although crested wheatgrass is not a native bunchgrass to the area, it has been used in plantings for over 100 years and is considered by many to be naturalized. Crested wheatgrass is commonly planted on public and private lands to improve available forage and to prevent invasion by annual grasses after a wildfire.
Crested wheatgrass often grows in large, dense, upright bunches. The old seed heads remain most of the year and are reminiscent of a fish bone or herringbone design (Figure 14).
Crested wheatgrass has long, slender, yellow auricles at the collar. Unlike bluebunch wheatgrass, the leaf blade is much wider than the culm and balloons out at the collar (Figure 15).
Based on physical characteristics, these two species, crested wheatgrass and bluebunch wheatgrass, were once in the same genus, Agropyron spp. They have since been separated, but it is helpful in the field to compare the vegetative characteristics of these two grasses.
bottlebrush squirreltail
Elymus elymoides (Raf.) Swezey ssp. elymoides
Bottlebush squirreltail is highly variable. Its bunch can appear dark, glossy green and tall like bluebunch wheatgrasss. It can also be small, light green and with fuzzy leaf blades (Figure 16A-D). As they weather, last year’s leaf blades often form white corkscrews throughout the base of the bunch. These corkscrews are visible even in winter.
Auricles can be present or completely absent (Figure 16C) on bottlebrush squirreltail. The young seed heads look like a squirrel’s tail and the ripe seed heads spread out like a bottlebrush (Figure 17A). After the seeds ripen, the entire seed head will break off and blow away like a small tumbleweed, leaving behind a pinwheel of glumes (Figures 17B and 17C). Before these seed heads ripen, they can be easily confused with robust medusahead.
Idaho fescue
Festuca idahoensis Elmer
Idaho fescue is a fine-leafed, dense bunchgrass with open, lacy seed heads. The leaves are fine, tightly rolled and smooth (Figure 18A, B). This is the only species in the northern Great Basin with black roots (Figure 18C). Clumps of Idaho fescue can be pulled out of the ground with a good tug, but be sure to grasp tightly at the very base of the tillers. The leaves are fine and break off easily as you try to pull, especially in winter. In the northern Great Basin, black roots on a bunchgrass mean it is Idaho fescue. However, finding a few white roots in spring does not rule it out as Idaho fescue, because newly grown roots can be white and fleshy (Figure 22B).
Idaho fescue leaf blades are at a strong right angle, standing straight up like the back of a wooden chair when viewed from the side. (Figure 19A, B). Northern Great Basin species’ collars look less upright and more reclined, like an easy chair. This leaf collar shape is also helpful in winter when it is difficult to pull the black roots out of the ground. The ligule is green, translucent and hard to distinguish from the rest of the collar. You will want to compare these traits to Thurber’s needlegrass (Figure 22).
Thurber’s needlegrass
Achnatherum thurberianum (Piper) Barkworth
Thurber’s needlegrass has a distinct seed (Figure 20B). But without seed heads, Thurber’s needlegrass can be easily confused with Idaho fescue. Like Idaho fescue, Thurber’s needlegrass forms a short, compact bunch (Figure 20A) with fine, tightly rolled leaf blades. However, these leaves are typically stiffer than Idaho fescue and feel like sandpaper when you stroke them from top to bottom. Thurber’s needlegrass bunches form upright tufts, whereas the Idaho fescue bunches form softer, rounded mounds. Thurber’s needlegrass seems to stay green later into the summer than other bunchgrasses.
The ligule on Thurber’s needlegrass is a long, nearly transparent flag that extends down the leaf sheath. The example in Figure 21 is nearly a centimeter long. This ligule is easy to find on early spring growth, flowering plants, and even dead tillers in the middle of winter.
Thurber’s needlegrass has thick, buff-colored roots, while Idaho fescue has black roots (Figure 22B). These samples were pulled in early spring. Notice that the Idaho fescue does have some new white roots that will blacken with time. The glumes on the Thurber’s needlegrass are longer and wider than those of Idaho fescue. This feature is even visible on old seed heads in winter (Figure 22C).
What to look for
Thurber’s needlegrass has four characteristics that distinguish it from Idaho fescue:
- It has distinctive, long ligules that appear nearly translucent until gently pulled back (Figure 21).
- Its leaf collars are not at a right angle (Figure 22A) like Idaho fescue’s “wooden-back chair” leaf collars.
- It does not have black roots. Thurber’s needlegrass roots are thick, fleshy and buffcolored (Figure 22C).
- The fine, tightly rolled leaves are stiff and sandpaper-like when rubbed tip to base.
needle-and-thread grass
Hesperostipa comata (Trin. & Rupr.) Barkworth ssp. comata
Needle-and-thread grass is a less common grass species in the northern Great Basin, but appears on many sites with bluebunch wheatgrass and Idaho fescue. It often indicates that the site has sandier soils. This plant may have growth habits similar to bluebunch wheatgrass, but the bunches tend to be looser, its leaves broader (Figure 24C), and the long ligules are distinct even in winter (Figure 23A). The seed awns are very long (4–8 inches), straight and often mature to a dark black (Figure 24A, B).
Needle-and-thread grass compared to Thurber's needlegrass
Needle-and-thread grass has:
- Broader, flatter leaf- larger looser bunch
- Wide ligule — still very long, generally a bigger culm and leaf (Figure 32B).
- Seed awns are straight and longer by several inches.
Needle-and-thread grass compared to bluebunch wheatgrass
Needle-and-thread grass has:
- Longer, wider ligule, visible even in winter
- No auricles at leaf collar.
- Seed heads are a loose panicle (not a spike like bluebunch wheatgrass, Figure 12A)
These differences would be evident even with dead winter materials.
prairie Junegrass
Koeleria macrantha (Ledeb.) J.A. Schultes
Prairie Junegrass has distinctive seed heads evident through much of the year (Figure 25). New seed heads have a shimmery, reflective quality when held angled to the sun. This plant, without seed heads present, may be confused with bottlebrush squirreltail at first glance. However, the leaves and culms are thicker, fleshier and often have a yellow-orange tint near the tiller’s base
The prairie Junegrass ligule is large, white, thick and rounded; the edges are scalloped and a bit ragged (Figure 26A). The dead material does not form corkscrews like bottlebrush squirreltail, and old, dense seed heads can be found most of the year. Be sure to look on the ground for old materials or on nearby plants for comparison.
Indian ricegrass
Achnatherum hymenoides (Roemer & J.A. Schultes) Barkworth
Indian ricegrass has a large, round, open bunch with stiff, round culms (Figure 27A). The leaves tend to roll into a tight round tube (Figure 28). The seed heads are distinctive, open, lacey panicles that can be found year-round (Figure 27B, C). The panicle’s branched, tree-like seed-head structure is in sharp contrast to the spike structure found on bluebunch wheatgrass in Figure 12A. If the Indian ricegrass does not have seed heads, check the base of the plant for old seed heads knocked down by snow or wind.
Without any seed heads present, Indian ricegrass may look similar to prairie Junegrass. However, the leaves, sheaths and culms of Indian ricegrass are smoother, stiffer and rounder than prairie Junegrass. The ligule on Indian ricegrass is white, smooth-edged and half-moon-shaped (Figure 28). Prairie Junegrass’s ligule is shorter and ragged (see also Figure 26A).
basin wildrye
Leymus cinereus (Scribn. & Merr.) A. Löve
Basin wildrye is a large bunchgrass. The example in Figure 29A is 5 feet or taller. The seed heads are hand-length (Figure 29B). When size cannot be used as an identifying factor, such as when it is a seedling or after fire, then the nodes and ligule can help identify it. The ligule, like everything else on basin wildrye, is large (Figure 30A,B), and the leaves are much wider than the culm (Figure 30C). The area beneath the nodes (joints/knuckles found along the culm) are constricted and narrower than the culm (Figure 30D).
Sandberg bluegrass
Poa secunda J. Presl
Sandberg bluegrass is the most common shallow-rooted perennial grass in the northern Great Basin. It grows in short (2- to 4-inch tall), tight bunches that often form pedestals. It is the first perennial bunchgrass to grow in spring and the first to turn brown and drop seed in summer (Figure 31; see also Figure 3). Their leaf blades are typically flexible, smooth and folded down the center. You should look for the “railroad tracks” that are formed by two prominent veins at the center of each unfolded leaf (Figure 32A). The ligule is white, tent-shaped and easily visible without a hand lens. (Figure 32B).
In the northern Great Basin, this plant is famous for growing into and around the bases of larger, deep-rooted perennial grasses. It is common to see ripe Sandberg bluegrass seed heads emerging from the edge or center of a bottlebrush squirreltail or bluebunch wheatgrass that has just begun to green up in spring.
Although not deep-rooted, these plants have extensive lateral roots that are effective at capturing rainfall from brief rain events. These spreading roots allow Sandberg bluegrass to stiffly compete with emerging native grass seedlings. In the northern Great Basin, Sandberg bluegrass is often separated from the deep-rooted bunchgrasses into a shallow-rooted bunchgrass functional group of its own.
Annual grasses
Invasive annual cheatgrass, medusahead and ventenata, or North Africa grass, are increasingly common in the northern Great Basin and can be detrimental to native species. While many can identify them when seed heads are present, here are several ways to recognize these grass species throughout the year. See the Extension publication Recognizing and Identifying three invasive annual grasses in the Great Basin desert (EM 9188) for more information about identification and control of these species.
cheatgrass
Bromus tectorum L.
These annual grasses can be as small as a single tiller, can form tight mats, or can be as large as some perennial grasses when resources are plentiful. Seed heads, both fresh and dead, are easily identifiable. As an annual, cheatgrass invests heavily in reproduction, and the heavy seed heads will bow over under the weight (Figure 33E). Notice even the tiny individual in Figure 33D has a seed head.
Cheatgrass has a long, shaggy ligule that is noticeably larger than bluebunch wheatgrass, crested wheatgrass or bottlebrush squirreltail (Figure 33A, B). The leaf sheath is pubescent, meaning it has sporadic, long, thin hairs that are especially visible on adult plants. An entire plant may be covered in long hairs or may even appear velvety (Figure 33C). As cheatgrass enters the dormant stage, it often turns a purplish color, as seen in Figure 36A.
medusahead
Taeniatherum caput-medusae (L.) Nevski
Medusahead is an aggressive invasive grass that thrives in disturbed sites. Like cheatgrass, medusahead is easy to identify when in large patches or when the seed heads are fully formed (Figure 34, 36). Seed heads form quickly and persist throughout the growing season, aiding identification. Medusahead can form large individuals with many tillers (Figure 34C) or solid mats that dominate a landscape (Figure 36B). In spring, these larger plants may be confused with bottlebrush squirreltail. But unlike bottlebrush squirreltail, medusahead seed heads do not break apart and tumble away (Figures 17, 35). Furthermore, medusahead seed heads have awn-like glumes that remain even after the seed has shattered. These empty seed heads remain into the winter.
When distinguishing bottlebrush squirreltail from medusahead, consider that bottlebrush squirreltail is a perennial with a deep root system and many generations of tillers. You would need a shovel to dig up a flowering/reproductive bottlebrush squirreltail bunch.
Medusahead, however, is an annual that can be easily pulled from the ground by hand.
Large monocultures of medusahead plants forming a solid mat have a distinct light green color when growing and a pale straw color when dormant (Figure 36 A, B).
If you are trying to identify medusahead seedlings before they have produced seed heads, you can dig them up and look for the remainders of the seed coat and seed awn. This material will stay attached to the seedling for most of the year (Figure 36C). See Recognizing and identifying three invasive annual grasses in the Great Basin desert (EM 9188) for more information about and control of this species.
ventenata (North Africa grass)
Ventenata dubia (Leers) Coss.
Ventenata is one of the newer invasive annual grasses in the northern Great Basin. Like medusahead, this invasive annual grass also has a bright green color in the spring (Figure 37D). If ripe seed heads are present, it can be identified by its open panicle and bent awns (Figure 37A). Notice how the early spring panicles have yet to mature and remain constricted (Figure 37B). As the seed heads flower and ripen, the panicle will open and more closely resemble the illustration.
Before seed head emergence, the visible, clear ligule helps with identification (Figure 37C). See also Recognizing and identifying three invasive annual grasses in the Great Basin desert (EM 9188) for more information on and control of this species.
Tips: seedling identification
Land managers who evaluate the success of restoration or drill-seeding project require accurate identification of grass seedlings. Seedlings with three or more leaves produce a leaf collar that has the same characteristics as the adult plants (Figure 38A).
If you can dig up a few sample plants, the seeds are often still attached to the seedlings. Figure 38B illustrates two excavated seedlings with the seed still intact. This technique is especially useful with cheatgrass and medusahead. These two annual grasses have distinct seeds and awns that lend themselves to quick identification. Sometimes you can see medusahead’s long black awn sticking out of the dirt right next to the newly emerged seedling (Figure 36C).
Growth rates and phenology (life stages, such as timing of flowering) can also be used to distinguish species. See Bunchgrass phenology: Using growth stages of grasses as adaptive grazing management tools (EM 9276) for more information on the phenology of several common bunchgrasses native to the Great Basin.
Figure 39 shows two examples where growth rates can help with identification. In the top photo (Figure 39A), the circled seedling on the left is cheatgrass, which grows faster and is more robust than the bluebunch wheatgrass seedling on the right. The bottom photograph illustrates how crested wheatgrass often grows faster and more robustly than the bluebunch wheatgrass seedlings on the left (Figure 39B). Once you are familiar with the species in your seeding project, you will begin to recognize these differences in the field.
Tips: plant collection and working with a botanist
Whether you are collecting plant materials for a botanist to identify for a permanent collection at your agency or just to record the species found at a given site, you should follow several steps:
- COLLECTION: Collect the entire plant, including roots, leaves and flowers (Figure 40). More than one example of a plant is helpful. If you’re taking photos, try to anticipate what features a plant key will ask for and document those as clearly as possible. Take detailed photos, front and back, of any flowering structures or seeds if present. Photograph the entire plant, including roots, and take close-up photos of leaves, nodes, ligules, collars and other distinguishing features. Have a ruler or other known object to help with scale (Figure 40B). Most plant keys ask for size ranges of key features.
- PRESERVING FOR LATER IDENTIFICATION: When collecting fresh plants, you should press your plants while in the field using a “cardboard-blotter paper-newspaper” sandwich (Figure 41). If you do not have one with you, place delicate samples between the pages of a glossy magazine, and store in a large resealable plastic bag. If possible, store the sample in a cooler until you can more permanently preserve it.
- LOCATION, LOCATION, LOCATION: Plants are an expression of a site’s history, soil and climate, but a plant sample is useless without a location description, date and habitat information. This data helps a consulting botanist identify the plant and makes the specimen more useful in a permanent collection. Figure 42 is an example of a herbarium label used around the world. Record your location with GPS if possible. If you are photo documenting, take a habitat photo at each collection site.
Helpful hints:
- Newspaper has antifungal properties and allows you to change the blotter papers without disturbing the plant.
- Sticky-note pads are helpful when arranging a plant for pressing. They can hold a plant in place and still allow the papers to breathe. It is also a handy place to write notes.
Perennial bunchgrass cheat sheet
Annual grass cheat sheet
|
Common name |
Most current synonyms |
Code |
Historical synonyms |
Historic code |
|---|---|---|---|---|
|
basin wildrye |
|
LECI4 |
|
ELCI2 |
|
bluebunch wheatgrass |
|
PSSPS |
|
AGSP |
|
bottlebrush squirreltail |
|
ELELE |
|
SIHY |
|
cheatgrass |
|
BRTE | ||
|
crested wheatgrass |
|
AGCR | ||
|
Idaho fescue |
|
FEID | ||
|
Indian ricegrass |
|
ACHY |
|
ORHY |
|
medusahead |
Taeniatherum caput-medusae (L.) Nevski | TACA8 |
|
TAAS2 |
|
needle-and-thread grass |
|
HECOC8 |
|
STCO4 |
|
prairie Junegrass |
|
KOMA |
|
KOCR |
|
Sandberg bluegrass |
|
POSE |
|
POSA12 |
|
Thurber needlegrass |
|
ACTH7 |
|
STTH2 |
|
ventenata, (North Africa grass) |
|
VEDU |
Source: National PLANTS Database. USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 3 February 2021). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Glossary of terms
Annuals: plants that grow from seed and then die, completing their life cycle within a year.
Auricle: protrusions at the leaf collar’s edge — similar to “hangnails” (Figure 11)
Bunchgrass: a grass that grows in a single bunch from one root system. Different growth form than a turf. (Figure 1).
Cotyledons: the first leaves to emerge from a seed, found at the base of the stem or tiller. Only visible on annual plants or perennial plants newly emerged from a seed (Figure 1).
Culm: the portion of a reproductive grass tiller that is the stiffer, stalk portion that supports the seed head.
Forbs: broad-leafed plants without significant woody tissue but which often have showy flowers.
Functional groups: categories of plants grouped together based on similar growth habits, physical features and roles within the plant community.
Glabrous: smooth, free from hairs or “fuzz.”
Glumes: two modified leaves that surround the base of individual flowers on a grass seed head. (Figure 17 and Figure 22C).
Invasive species: a non-native species that spreads quickly or “invades” an area, causing harm or damage to the environment.
Leaf collar: the area where the leaf blade separates from the leaf sheath and the blade starts to grow. Key parts of the leaf collar are the sheath, the blade, the auricles and the ligule (Figure 11).
Leaf sheath: the leaf material that wraps around the stiff culms on reproductive tillers and other younger leaves on vegetative tillers. Leaf blades grow from the collar of the leaf sheath.
Ligule: an extra piece of tissue that forms at the junction of the leaf collar and the leaf blade, similar to a “cuticle” on a fingernail. Ligules take numerous forms, and can be smooth or shaggy, pointed or flat (Figure 11).
Nodes: joints or knuckles found along the culm (e.g., Figure 30D).
Pedestaled bunchgrass: a bunchgrass raised above the soil surface, sitting on an elevated platform held in place by its root system.
Perennials: plants that use energy stores to come back year after year.
Pilose: covered with many hairs, can appear “fuzzy” or “velvety."
Seed shatter (seed ripe): the plant stage following the reproductive stage in which seeds have fully developed, ripened and dried out, “shattering” and falling from the plant.
Reproductive stage: during the reproductive, or flowering, stage of the grass plant, culms and seed heads emerge from leaf sheaths, beginning reproduction. This is followed by seed development, and this stage ends once the seeds ripen and dry out.
Rhizome: a stem located underground that grows horizontally and periodically sends out aboveground tillers from nodes. It is this structure that gives some grass plants a “turf” growth form.
Seed awn: a stiff, hair-like strand that grows from the end of modified leaves that surround a grass seed (e.g., Figure 20C).
Seed head: the reproductive portion of a grass plant that develops seeds following flowering (Figure 10).
Seed head structure: panicle vs spike: panicle seed heads are open and branching, with a central stalk and seeds growing off of branches from the main stem (for exammple, Figure 22A). Spike-type seed heads have seeds that grow directly on the main stem of the seed head (for example, Figure 12A).
Tap root: a large root that grows straight down and is usually longer, thicker and straighter than other roots that grow laterally outward.
Tiller: the individual unit of a grass plant (Figure 10).
Turf: a mat consisting of grass tillers, rhizomes and roots. Different growth form than a bunchgrass.
Vegetative tiller: a grass tiller that will not produce a seed head, consists of only leaf sheaths and blades.
Vigor: the expression of a plant’s vitality in response to its environment, including its size, growth rate and health.
Additional resources
Extension publications
Brummer, F., P. Schreder, G. Haskins, and J. Jaeger. 2018. Recognizing and identifying three invasive annual grasses in the Great Basin desert. EM 9188. Corvallis, OR: Oregon State University Extension Service.
Schroeder, V., and D. Johnson. 2019. Bunchgrass phenology: Using growth stages of grasses as adaptive grazing management tools. EM 9276. Corvallis, OR: Oregon State University Extension Service.
Schroeder, V., and D. Johnson. 2018. Western roots: Diving into a sagebrush sea of diversity. PNW 714. Pacific Northwest Extension, Oregon State University, University of Idaho, Washington State University.
Johnson, D. D. and K. W. Davies. 2012. An introduction to using ecological site descriptions as a management tool. CL598. In: J. R. Adams (Ed.). Cattle Producer’s Library (3rd edition). University of Idaho, Moscow.
Dichotomous keys
Baldwin, B.G., D.H. Goldman, D.J. Keil, R. Patterson and T.J. Rosatti (Eds.). 2012. The Jepson manual: vascular plants of California. University of California Press.
Cronquist, A., A.H. Holmgren, N.H. Holmgren, J.L. Reveal and P.K. Holmgren. 1977. Intermountain flora: vascular plants of the Intermountain West. Academic Press, New York, New York, USA.
Harris, J.G., and M.W. Harris. 1994. Plant identification terminology: an illustrated glossary. Utah: Spring Lake Publishing.
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