Decoding Grass Anatomy..
To establish, manage and maintain a first class grassed surface, it is necessary at least to recognise the common name of the grasses we wish to manage and grow. To do this, we must be able to distinguish (by eye) the differences between them.
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Grasses are as diverse as we are. Many have preferences for the type of soil they grown on, types and amounts of nutrition, pH, moisture conditions and general management received. They also have many diverse features for us to use to identify them as individuals. Who would have thought!
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If we can understand and recognise their genus, then we can manage grasses of our chosen type to its/their fullest extent. This ensures, encourages and maximises growth while discouraging any competition.
Structure of the grass plant
​Morphological characteristics of turfgrass plants play a vital and important role in aiding (a) identification (b) establishment and (c) subsequent management practices.
Understanding the general make-up of the turfgrass plant allows us to adjust management regimes to suit individual or collective plant needs this will allow us to complement and improve their growth and development. This also allows us to fully understand timeframes required to recover them from damage.
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Turf grasses can exhibit three types of growth habit, or combinations of these. The growth habit determines how the plant develops, establishes and spreads.
Turfted or Bunched Type
Tufted or bunch type growth allows the plant to spread new leaves through tillering (a form of new stem) from its base or growing point. All turf grass plants tiller, although those that grow strictly through tillering are termed tufted or bunch-type.
Turfgrasses that exhibit this type of growth (i.e Ryegrass (Lolium perenne), Yorkshire fog (Holcus lanatus) ‘fill-in’ very slowly, therefore the ability of these types of grasses to recover from wear or disease is generally slower. Seeding rates generally have to be higher and a greater attention paid to seed coverage to minimise any voids appearing.
Rhizomitous
​Grasses that are able to spread through ‘underground’ stems are termed rhizomatous in growth habit. Smooth meadow grass (Poa pratensis) is an example of this type.
Daughter plants form from nodes on the white fleshy rhizomes as they spread. Rhizomatous growth forms a very dense turf. This characteristic allows any spaces in the sward to be ‘filled-in’ (over-time) therefore recovery from damage is faster than the tufted type.
Stoloniferous
Some turfgrasses such as Creeping bentgrass (Agrostis stolonifera) Rough-stalked meadow grass (Poa trivialis) and Bermuda Grass (Cynodon Dactylon) have the ability to grow with ‘overground’ stems called stolons.
Stoloniferous growth is similar to rhizomatous growth except that the fleshy stem grows, this time, ‘above’ the ground and along the surface.
Vegetative Characteristics
There are many vegetative features on the grass plant that aid us in identification of genus and species. Perhaps the most important are the leaf blade and collar regions. As there are variations within these areas that aid in positive identification.
Vernation
Vernation is the term used to describe how the youngest shoot (leaf) is formed as it comes out of the stem. Grasses with ‘folded’ vernations have leaves that are folded in a V-shape as they grow out of the stem. Leaves with a ‘rolled’ vernation means the youngest shoot coming from the stem is rounded with no folds present.
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Some are bristle-like in nature , having an appearance very similar to a bristle on a paint brush. If you find it difficult to determine by eye whether the youngest leaf is rolled of folded it is sometimes useful to hold the plant between finger and thumb, then try to roll it. If the grass rolls easily between your finger and thumb the vernation is rolled, if it lies flat, is difficult to roll and has flat edges, it is folded.
Another way to determine this would be to cut the plant just below the leaf blade and look directly down upon the cut.
The grass leaf blade varies in colour, width and hairiness. Some grasses have leaf blades that have a dominant vein running through the centre. Others have equally sized veins running up the blade parallel to each other. We can use this area to identify different species and narrow the identification down to specific types.
Leaf blades also vary in shape at the tip. Some terminate to a sharp point, while others are blunt or keeled (known as boat-shaped tip), again, some leaves have a bristle-like appearance such as many of the fescue grass species.
The collar region is located on the back of the leaf blade where it meets the leaf sheath on the stem. This region (to the front) is also the place where the ligule and the auricles (if present) can be found.
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The ligule is an opaque membranous tissue or fringe of hairs found at the junction of the leaf blade and leaf sheath. Ligules can vary in shape and size, can be membranous, hairy and even sometimes absent.
Auricles are appendages that are considered an extension of the collar. To this day it is unknown why these form part of the plants anatomy or to what purpose they serve, but these prove to be a great aid for identification purposes! Auricles can be long/claw-like, small/rudimentary, or absent.
There are many other parts of the plant that we can use to differentiate one genus and species from the other. Hopefully this will wet your appetite for more ..