**Botanical Characteristics of Poaceae**:
– Grasses have cylindrical stems with hollow nodes and alternate, distichous leaves with parallel veins.
– Silica phytoliths harden grass leaf blades to deter grazing animals.
– Flowers are arranged in spikelets with florets grouped into panicles or spikes.
– Grass flowers are mainly hermaphroditic and wind-pollinated, with reduced perianth scales.
**Growth and Adaptation of Grasses**:
– Grass blades grow from the base with low growth points to withstand grazing.
– Grasses exhibit bunch-type, stoloniferous, and rhizomatous growth habits.
– C3 and C4 grasses have different photosynthetic pathways, with C4 grasses adapted to hot, arid environments.
– Grass species are classified as cool-season or warm-season based on growth patterns.
**Economic and Ecological Importance of Poaceae**:
– Poaceae is the fifth-largest plant family with around 12,000 species.
– Grasses provide staple foods like maize, wheat, rice, barley, and millet.
– Grasslands cover around 40.5% of Earth’s land area, excluding Greenland and Antarctica.
– Grasses dominate habitats like grasslands, salt-marshes, and steppes, providing food for various animals.
**Human Utilization and Industry Applications**:
– Grasses are economically important for food production, industry, and lawns.
– Grasses are used in construction, insulation, paper production, and biofuel.
– Grasses are grown as pasture for livestock and utilized in various products like paper, fuel, clothing, and construction materials.
– Turf grass varieties are developed and marketed for sports surfaces.
**Scientific Research and Cultural Significance**:
– Grass phylogeny, ecological roles, and impact on ecosystems have been studied.
– Grass-related aphorisms and myths have cultural significance.
– Scientific studies on grasses include pollen studies, botany, ecology, and paleontology.
– Grass has been cultivated and consumed for thousands of years, with various grass species studied for their evolutionary relationships.
Poaceae (/poʊˈeɪsiaɪ, -siːiː/) or Gramineae (/ɡrəˈmɪniaɪ/) is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in lawns and pasture. The latter are commonly referred to collectively as grass.
Grasses Temporal range:
| |
---|---|
![]() | |
Flowering head of meadow foxtail (Alopecurus pratensis), with stamens exerted at anthesis | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Clade: | Commelinids |
Order: | Poales |
Clade: | Graminid clade |
Family: | Poaceae Barnhart |
Type genus | |
Poa | |
Subfamilies | |
Synonyms | |
Gramineae Juss. |
With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae.
The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as feed for meat-producing animals. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%, wheat supplies 20%, maize (corn) 5.5%, and other grains 6%.[citation needed] Some members of the Poaceae are used as building materials (bamboo, thatch, and straw); others can provide a source of biofuel, primarily via the conversion of maize to ethanol.
Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath. The leaf grows from the base of the blade, an adaptation allowing it to cope with frequent grazing.
Grasslands such as savannah and prairie where grasses are dominant are estimated to constitute 40.5% of the land area of the Earth, excluding Greenland and Antarctica. Grasses are also an important part of the vegetation in many other habitats, including wetlands, forests and tundra.
Though they are commonly called "grasses", groups such as the seagrasses, rushes and sedges fall outside this family. The rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of the order Alismatales. However, all of them belong to the monocot group of plants.