Grass
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Grass is the common name for any of the members of the taxonomic family, Poaceae. The grass Family is the fourth largest family of plants with a truly world wide distribution. Its taxonomy alone has around 700 genera and about 11,000 species. Aside from the name Poaceae, it is also called Gramineae.[1] These plants are known to take over and dominate very large areas like meadows and fields. And even though it has given many good things to the world, it can be a hazard because of its ability give off pollen. This factor is important because of the increase in hay fever victims. That's why people with grass allergies must be careful to move away from grassy areas like these in case they might succumb to the sickness. [2]
Anatomy
Grass comes in the form of mats on dirt planes.[3] The structure of a single Poaceae plant starts from the roots under the ground. The roots sprout from rhizomes and stolons that extend horizontally from the plant. Stolons also branch out into shoots, vertically. As the plant comes up out of the ground, the crown begins at the base, which is important to being perennial. As it grows, blades and sheaths emerge from the culm nodes of the plant.[4] Attached to these appendages are leaves.[5] At the bottom of the blade and sheath, there is a section of meristematic tissue called the collar. Some kinds of grass plants also have buds forming at the nodes of the collar. This process, though, is seen throughout the plant. This is the standard for a single, vegetative grass plant. [6]
In different types of grass plants though, they also contain flowering growth. The structure is nearly the same except that towards the top, there is a peduncle, which is a part of the culm that holds the seed. In the seed, there are spikelets that are made up of florets, little, tiny flowers. [7] These florets can be either male or female and are made of lemma, palea, and lodicules. [8]
Florets are usually hidden by the grass plant and thus are assumed to not be present. They contain pistils and stamens. The seed head of a grass plant has about 100 spikelets. [9] These spikelets are connected to rachis, the central section of the seed head. Most flowering plants have this same structure. [10]
Reproduction
Poaceae plants have two types of reproduction: sexual and asexual. Stolons and rhizomes that grow sideways on the surface or below it have separate culms that they develop at their nodes or joints. They'll eventually turn into new plants. This is called tillering. Intravaginal tillering is when the shoot emanates vertically from the leaf sheath and the original plant. Extravaginal tillering is when the shoot first moves away horizontally from the main plant and then grows straight. These tillers are either rhizomes if they grow underground or stolons if they grow just above it. [11]
Another way of reproduction is by pollination. Because of grass flowering growth, grass plants usually carry out this process by the wind. Within a floret of a plant, there are both pistils and stamens. Each floret can release about 20,000 pollen grains at a time when the months of May, June and July roll around. They will wither once their pollination is done. Grass plants have curious times on which they reproduce. The majority of plants will pollinate around 6 to 7 in the morning. On the other hand, other kinds of grass plants will pollinate at different times, like oats, which pollinate around 2 to 4 in the afternoon. [12]
Ecology
Grasses are found in almost every environment throughout the world. They can be found in areas such as forests, deserts, and even in bodies of water like lakes. Grass is distributed to the furthest reaches of countries and continents. They grow over large areas, often expanding. [13]
Grass plants like Coix lacryma-jobi are found in Asia. They grow primarily in the summer and prefer wet, moist areas like swamps to live in. [14]
Importance
Grass is beneficial to the economic world because it provides industries for humans such as wheat, rice, corn, and many more. Countries seek to better the conditions of grasses for vegetation and public use.[15] Not only are they used for their vegetative growth, but they're also processed into materials for building and furniture. [16]
Gallery
Big bluestem
(Andropogon gerardii)
Job's Tears
(Coix lacryma-jobi)
Southern crabgrass
(Digitaria ciliaris)
Lovegrass
(Eragrostis)
References
- Classification USDA.
- General Description of Grass Growth Llewellyn L. Manske PhD.
- Poaceae Botit.botany.wisc.edu.
- Poaceae the Grass Family Utah State University.
- Grass Structures Oregon State University.
- Grass Facts Old and Sold: Antiques Digest.
- Coix lacryma-jobi L. Fao.org.