spikelet: a flowering unit comprised of one or more florets enclosed by two glumes (bracts). The blade — the expanded part of the leaf — may be. Both rhizomes and stolons bear roots at the underside of the nodes. If depleted too quickly, the turf may go into the summer months in a weakened state. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and pasture. grass floret • Ligule: in grasses, a papery, hairy or membrane-like extension at the summit of a leaf sheath GRASS SPIKELET/FLORETS Illustration from Wetland Plants and Plant Communities of Minnesota and Wisconsin, Version 3.1 by Eggers and Reed (2014) Floret BOTANICAL TERMS: GRASSES • One-flowered spikelets • Spikelets more than one-flowered The florets are borne in two ranks on the rachilla. Roots, branches and sometimes leaves are attached to the stem. Depletion of carbohydrates is fastest in spring, especially under low mowing heights and high nitrogen fertility. Happy in just about any, average soil. This process is so gradual that the transition is unnoticeable. Branching at the base of the main stem may produce erect shoots; horizontal, above-ground stolons (stoloniferous) ; or horizontal, below-ground rhizomes (rhizomatous). Behind the region of cell elongation, cells begin to develop into tissues that absorb water and nutrients. View our privacy policy. New shoots are produced from nodes or from tips of the stolon as it turns upward. All Grass Types Are Divided Into Two Categories. Kentucky bluegrass is a turfgrass with a panicle-type seed head. Grass roots are generally fibrous and seldom penetrate more than 1 metre below the surface. Bermuda Grass 2. 1 shows these basic structures. The collar region is located where the blade and sheath meet and may or may not have structures called the collar, ligule, and auricle (Fig. In the panicle type, the spikelets are borne on branches that are arranged along the central or main stem. The basic unit of the seed head is called the spikelet. They also provide interest in the fall and winter garden, becoming key features ogf the garden during the cooler months with their spectacular feathery plumes. As the surface water is depleted, roots begin using up water deeper in the soil. Most of us assume that grass is grass and that the types growing in our own yards are the same types growing everywhere else. The embryo contains the beginnings of the leaves, growing points, and roots of the grass plant. Below ground is the network of plant material called the root. Roots grow from the underside of the nodes; shoots (stems and leaves) grow from the topside. Some grasses have stems which creep along the surface of the ground and give rise to new shoots (TILLERS) at their nodes. Stems of most perennial grasses die back to the approximate base of the stem each year. The meristem is protected from the abrasive effects of the soil by a structure called the root cap. An Answer to a Commonly Asked Question Meristem, region of cells capable of division and growth in plants.Meristems are classified by their location in the plant as apical (located at root and shoot tips), lateral (in the vascular and cork cambia), and intercalary (at internodes, or stem regions between the places at which leaves attach, and leaf bases, especially of certain monocotyledons—e.g., grasses). The sheath is the portion of the leaf that envelopes the shoot or stem. 13). This article covers the basic structures of grass plants, how they grow and develop, and how to identify the different species of cool-season turfgrasses. There are three main grass inflorescence types: 1. panicle, 2. spike, 3. raceme. The internodes, the part of the stem between two nodes, are usually hollow. Types of stem. Fine fescue is actually a grouping of various fescue species of grasses such as chewings fescue, hard fescue, red fescue, and sheep fescue. The study of cool-season turfgrasses begins with learning the basic structures of grass plants and how they develop from seed to mature plants. The tallest of the grasses, especially when the summer season is blessed with adequate rainfall, is the Big Bluestem. The blade is long and narrow and grows more or less horizontally away from the main shoot. Each floret consists of one flower or seed enclosed in two papery membranes called lemma and palea. The collar region of a grass leaf with ligule and auricle. Once you understand how turfgrasses grow and develop, it is easier see how they function as long-lived communities and how they tolerate traffic, mowing, and other problems. Meanwhile, among the warm-season types, Bermuda grass, centipedegrass, and zoysiagrass are cold-tolerant enough to be grown there. You must have JavaScript enabled in your browser to utilize the functionality of this website. Stolons. Mow regularly (to a height of two to three and one-half inches), fertilizing and watering appropriately, and overseeding in the fall. However, crowns can be damaged by mowers when blades are set too low. Figure 4. A horizontal, above-ground stem that roots at the nodes (found in the crown) and gives rise to new grass plants. Stolons are green and can creep over other grasses and bare spots in lawns, often forming circular patches. Because new leaf growth occurs at the base of the plant, grass plants can tolerate mowing and some other types of minor injury to leaf blades. It should be noted that Bermuda doesn’t tolerate shade well and you may have to plant a separate shade grass in those areas. The caryopsis is made-up mainly of the embryo and endosperm. These are aerial culms, underground rhizomes and stolons which Turfgrass root growth is affected mainly by soil temperature, moisture, and oxygen. The jointed stem (culm) of a grass plant consists of nodes and internodes. A grass leaf is divided into three parts: the blade, sheath, and collar region (Fig. Figure 2. The amount of water the roots absorb will depend primarily on the number of roots, the depth of rooting, and the amount of water in the soil. Leaf growth increases with increasing daylength as long as temperatures are within the optimum range and moisture is adequate. There are two types of root systems in grasses, the primary and the secondary. The basic requirements for germination of turfgrass seed are adequate moisture, favorable temperatures, and oxygen. 14). An underground stem that produces a new plant. Figure 8. These ridges are the beginnings of the new leaves. In the raceme type, spikelets are borne on very short branches along a main stem. The amount and frequency of top-growth removal by grazing or mowing have a marked influence on root growth. Once the stand is established though, rotational 2). Stems are rarely branched above the ground and are called CULMS. Rhizomes and stolons begin to grow from nodes in the crown and break through the surrounding leaf sheaths to spread laterally. Of the two main grass varieties, there are many types that each requires special attention and care to achieve the best and healthiest growth. 3). The jointed stem (culm) of a grass plant consists of nodes and internodes. The end products, carbohydrates, are used by plants for energy and growth and are the true plant food. It gives rise to leaves, secondary roots, and other stems. Some other grasses (mostly warm-season grasses and weed grasses) have long rhizomes that produce nodes that can branch and produce shoots and roots, forming new plants. 100 Native Forage Grasses in 11 Southern States, (Technical information developed by the Federal government is generally in the public domain and is not copyrighted. 6). The sheath is borne at the node and surrounds the stem like a tube. These sheaths act as protective coverings for the roots. As the leaf expands and elongates it begins to produce its own food through a process called photosynthesis. The entire caryopsis is surrounded by the pericarp, sometimes referred to as the ovary wall (Fig. Cheat grass is an invasive weed in the Western U.S. Urban dwellers may notice winter annual grasses along roadways, which also require pre-emergent control. Spike is a seedhead in which one or more sessile spikelets are borne on the main axis (rachis). The difference between the two will be explained later in this section. Severely compacted soils have limited supplies of oxygen and will not support good root growth even when favorable temperatures and moisture levels are present. The rate of leaf growth is dependent on many factors including temperature, moisture, nutrition, and to some extent, daylength. 10). Jointed goat grass has a tall, jointed stem and poses problems in wheat fields because of its resemblance to the grain. Figure 12. Crabgrass, a common annual grass weed, has a modified spike-like raceme. Stolons grow above-ground and form nodes which give rise to new plants. It is usually a lighter color than the blade and may continue across the width of the leaf or be divided in half by a large mid vein. Sedge leaves typically lie along the stem in three vertical planes. Generally, the seedhead has no leaves. Leaves are parallel-veined. What it needs: Full sun. However, if it's newly established, grazing is not encouraged during the first season. They are herbaceous stems and woody stems. The first step in seed germination is absorption of water (sometimes referred to as imbibition). The lemma is borne on the rachilla above the pair of glumes and the palea at the base of the flower or seed. Grasses are examples of the following type of stem: (a) Suckers (b) Runners (c) Stolon (d) Rhizomes. The ridges are the beginning of new leaves. inflorescence: flower head terminating the stem, consisting of a collection of flowers arranged on a common axis. In the area just behind the meristem, new cells grow mostly in length. This leaf continues to elongate and expand and eventually forms a fully-developed leaf with a blade, sheath, and collar region. The growing point or meristem is located at the tip of the root. Turfgrass roots are fibrous, branching, and very slender. Figure 14. Brief descriptions and drawings of these parts follow : Grass roots are fibrous. All succeeding leaves follow the same route -- emerging from the growing point and growing upward within the folds of the older leaves. Grasses may have rhizomes or stolons and the collar regions have differing variations of ligules, auricles, and blades (laminas). In some grass species, rhizomes produce growing points (often referred to as nodes) which give rise to roots and shoots forming new or 'daughter' plants. 7). Figure 7. Although the primary roots continue to function for up to a year after germination, water and nutrient uptake is gradually taken over by the secondary roots (sometimes referred to as adventitious roots) which become more numerous as the grass plant matures. Some ligules are membranous or papery; some are only a ring of hair. Soon after germination, the coleoptile and first leaf begin to elongate and grow towards the soil surface. Individual tillers live for about a year and formation of new tillers is stimulated by cool temperatures, short daylengths, moderately low mowing heights, and high mowing frequencies. There are two types of chickweed which occur in gardens commonly; Cerastium vulgatum (the Mouse-ear chickweed) and Stellaria media (the common chickweed). A mature, unmowed grass plant is composed of leaves, roots, stems, and a seed head. However, this is completely untrue. Mature tillers produce leaves, stems, and root systems; thus, they can function independently of the mother plant. By entering your email, you consent to receive communications from Penn State Extension. All of the aboveground section of a grass is collectively called the shoot. The stem is another main part of a plant. Diagram of the root tip including meristem, root cap, region of cell elongation, and root hairs. The Following are the different types of grass: 1. A ligule is a thin piece of tissue that extends just above the top of the leaf sheath and can vary in size and shape. Carbohydrates can be stored in stem and crown tissues when they are made faster than they are used. Some species of grasses branch only at or near the base from axillary buds at the basal nodes. After flowering, growth slows down and stops during summer when soil temperatures are high. They have nodes and scales or well-developed leaves. Kathy also had heard: Sedges have edges, rushes are round, Grasses wear robes all the way to the ground. There are three basic types of stems in grasses. The collar is on the outside of the leaf at the junction of sheath and blade. They have nodes, internodes, and scalelike leaves. To see photographic examples of a term, click the camera next to it in the list of botanical terms. Horizontal stems begin to form in the crown and develop into rhizomes or stolons. Soils with loose, crumbly structure and good drainage are ideal for root growth and development. Since new secondary roots are produced from the crown, some of the existing root system can be damaged without killing the plant -- provided that the root-initiating portion of the crown is not injured. Why do we need this? LEARN HOW TO STOP THE INVASIVE SPOTTED LANTERNFLY, Coronavirus: Information and resources for the Extension Community, Turfgrasses are narrow-leaved grass species that form a uniform, long-lived ground cover that can tolerate traffic and low mowing heights (usually two inches or below). Collectively, grasses domesticated as crops represent the world's most important source of food. In the absence of a seedhead, the ligule is often used to identify a grass. Plants make their own food through photosynthesis, a chemical reaction in leaves involving water, carbon dioxide (CO2 ) and light energy. Both rhizomes and stolons bear roots at the underside of the nodes. However, in the basal part of the stem, there are from several to many basal nodes with axillary buds capable of initiating new growth. A grass's stem is only 1 to 3 milimeters (mm) in length, and found very close to the ground, almost below ground level. In … Tillers are shoots that develop from crown tissues and grow vertically within the sheaths that surround the crown (Fig. Improve soil drainage or water less frequently to dry the soil. Root hairs number in the billions for a fully-developed root system and can greatly increase the amount of soil the roots contact. Three types of turfgrass seed heads; panicle, spike, and receme. If you need to improve the look of your garden landscape and lawn, grass identification is essential to reseed the sod with a similar type of grass. Rhizomes are usually white. Hare’s-Tail Grass (Lagurus ovatus) Also called the bunny’s tail grass, the name comes from the feathery cream to white flower spikes that make excellent cut flowers too. Stolons are stems or runners that originate at the base of the main stem and grow along the surface of the ground. The optimum temperatures for root growth of cool-season grasses are lower than those for shoot growth. Figure 1. Turfgrass roots need an adequate supply of oxygen for normal growth and development. The leaves on grasses are usually two-ranked, which means they occur on two rows on opposite sides of the stems. The nodes (joints) are solid and usually larger than the rest of the stem. Rhizomes are a desirable trait in turfgrasses because they allow plants to send new shoots into areas that are thin or damaged by traffic, drought, and/or disease. Native Indian Grass is tolerant of an array of soil types, including heavy clay. The leaves on grasses are usually arranged in two rows on the sides of the stems. 9). The spikelet consists of a rachilla (jointed stem or axis), one to several florets, and two glumes. This area is called the region of cell elongation. Turfgrasses take-up water from the soil through their root system. The grass leaf consists of three principal parts: Blade, sheath, and ligule. It is an extremely hardy annual grass variety that can grow in all soil types from sandy to moist, well-drained soils. Figure 5. In general, grasses that are capable of producing the greatest top growth are also capable of producing the greatest root growth. Other parts are collar and auricle. Some species of grasses branch only at or near the b… Zoysia Grass The rate at which grass seed absorbs water depends on the amount of water present and the permeability of the seed. The smooth area on the back side of the leaf where the blade and sheath meet is the collar. 11). Diagram of a grass leaf, including blade, collar region, and sheath. Lawn fertilizers are often marketed as 'plant food'. The vegetative parts of a grass plant are roots, stems, and leaves. Grass Stems - are mostly hollow, cylindrical and interrupted at intervals by swollen joints or nodes. The crown is located in a protected position between the roots and shoot near the soil surface. 8). Raceme is a seedhead in which the spikelets are borne on individual footstalks (pedicels) growing directly on the main axis (rachis). Kentucky Blue Grass 5. Internode: Area of the stem between two nodes. Grasses differ widely in their ability to grow in saturated, poorly aerated soil. Soon after, the first leaf emerges from the seed. Water and nutrients are transported from root hairs to the interior of the root where special conducting tissues move water and nutrients to the leaves and shoots. The newest leaf is always on the opposite side of the stem from the leaf just below it. See All Pest, Disease and Weed Identification, See All Beer, Hard Cider, and Distilled Spirits, See All Community Planning and Engagement. Although most people realize that nutrients from fertilizers are required by plants for proper growth and development, they may not realize that fertilizers are not really plant food. The newly-laid sod generates a new root system from secondary roots formed in the crown. Others branch and rebranch from buds produced at upper nodes, giving the appearance of a dense bouquet. Rye Grass 6. As water is absorbed, the seed swells. Rhizomes are stems that originate at the base of the main stem and grow horizontally below the ground surface. Structures Used to Identify Grasses. Flower stems are also formed in the crown, usually in late spring or early summer in most cool-season grasses. Figure 3. Figure 11. Plants with herbaceous stems are only supported by water in the stem. True raceme seed heads are rare in grasses and none of the cool-season turfgrasses produce them. As nouns the difference between grass and grasses is that grass is (countable|uncountable) any plant of the family poaceae, characterized by leaves that arise from nodes in the stem and leaf bases that wrap around the stem, especially those grown as ground cover rather than for grain while grasses is . Herbaceous stems. Also, make sure to grow the most suitable type of turfgrass for the location (e.g., plant shade tolerant turfgrass varieties under trees). When temperatures reach 90°F in the surface inch of soil, Kentucky bluegrass root growth is greatly reduced. Germinating grass seed with radicle and first leaf breaking through seed coat. These roots are called primary roots and begin taking-up water and nutrients from the soil when they are fully developed. Kentucky bluegrass is the premier sod grass in the northern U.S. because its rhizomes allow turf to 'knit' and hold together as the sod is cut, rolled, and lifted. Poaceae ( / poʊˈeɪsiaɪ /) or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. The main stem is basically an extension of the flower stem. Different Types Of Grass – Bermuda One of the most used types of grasses in South Africa is Bermuda. (Technical information developed by the Federal government is generally in the public domain and is not copyrighted.). Rhizomes of Kentucky bluegrass. The diagram of a grass plant in Fig. Roots: Roots are the below-ground part of a grass plant that anchor it in the soil and take-up water and nutrients. Kentucky bluegrass is a desirable species for use in athletic fields because its rhizomes provide superior footing for athletes. Sod producers routinely sever a portion of the grass root system with sod harvesters, then transport the sod to a new location. According to research (Crider, 1955), the proportion of roots that stop growing varies according to the proportion of top growth that is removed. A spikelet, the basic unit of the seed heads. In some grasses, the sheath is open — the margins do not come together; in others, it is closed-the margins overlap. JavaScript seems to be disabled in your browser. Keep in mind that some grass species do not have all the structures shown and that mowed grasses typically lack flower stems and seed heads. As the name implies, fescue blades have a very fine, almost hair-like texture and do well in … Thus, the oldest leaves are on the outside of the plant and the youngest are located in the center of the plant. Soil factors influencing root growth are moisture, temperature, structure, depth, fertility, and chemical reaction. Secondary roots are produced from nodes in the crown or from nodes on horizontal stems. As a leaf begins to develop, it encloses the stem apex. Tillers increase the shoot density of lawns by replacing shoots that die in winter and summer. 4). It is characteristically split down one side, making it possible to separate the sheath from the stem without tearing the sheath. but it may grade from one form to another. It is very small (just a fraction of an inch long), white, and completely enclosed by leaf sheaths. This is where all new root cells are produced. Fine Fescue 4. Application of nitrogen fertilizer can greatly increase leaf growth if moisture and temperature are not limiting. Figure 10. native warm season grass types, Buffalograss is primarily used for range grazing, is an essential component of the shortgrass and mixed grass prairies, and can be used for all kinds of livestock. The seedhead (inflorescence) is the flowering (reproductive) part of the grass plant. Optimum temperatures for leaf growth among the cool-season turfgrasses range from 60° to 75°F. Soon after the radicle emerges from the seed, the first true roots develop from the embryo. Other factors that have an effect on root growth and development are soil pH, fertilization practices, salt concentrations, herbicides, diseases, and insects. These will be discussed in other sections of this manual. 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