About Grasses

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The grass family (Poaceae) is one of the largest and most cosmopolitan of the flowering plant families of the world comprising more than 10,000 species. Grasses are found almost everywhere (even Antarctica). They are adapted to a wide range of climatic and soil conditions, and grow in habitats ranging from deserts to freshwater and marine environments. Grasses form a major component of many vegetation communities e.g. grasslands, steppe, prairie and savannas.

Grasses are the most important plant family for humans. They provide a source of food (wheat, oats, maize, rice, sugarcane) and most of the grazing for wild and domesticated animals. Grass-use pervades all aspects of human endeavor: building materials, artistic pursuits, sports and leisure activities. New uses of grasses are still being found e.g. for environmental management. Humans have used grasses in a multiplicity of ways over a great period of time.

Suggested Native Grass Species for the Dry Tropics region

Suggested native grass species for some habitats are listed below.

Riparian grasses

  • Arundinella nepalensis
  • Enneapogon robustissimus
  • Eragrostis elongata
  • Sarga plumosum
  • Setaria surgens

Open woodland grasses

  • Alloteropsis semialata
  • Chrysopogon fallax
  • Cymbopogon bombycinus
  • Eragrostis elongata
  • Heteropogon triticeus
  • Sarga plumosum
  • Themeda triandra

Wetland grasses

  • Eragrostis elongata
  • Ischaemum australe
  • Sarga plumosum

Beach grasses

  • Eragrostis elongata
  • Setaria surgens
  • Thuarea involuta

The Grass Plant

The use of technical terms is necessary when describing grasses. The diagram below illustrates some terms which may be used in this booklet.

Drawing from Tothill and Hacker (1983)

Terminology:

Inflorescence – a group or cluster of flowers arranged on a stem.

Spikelet – for flower or seed.

Culm – stem.

Leaf blade – the expanded upper part of a leaf.

Ligule – a membranous or hairy appendage at the junction of sheath and blade.

Leaf sheath – the basal part of a grass leaf between the node and the ligule; at maturity it often comes away from the stem.

Node – the part of the stem from which the leaf arises, usually thickened. Tiller – new shoot.

Stolon – a trailing stem that produces roots at the nodes.

Rhizome – an underground stem, usually growing horizontally, producing roots at the nodes.

The Grass Inflorence

The basic grass inflorescence is composed of clusters of spikelets (flowers) arranged in a panicle which may be modified in a number of ways. The types of branching and the arrangement of spikelets on the branches determine the different types of grass inflorescence.

Raceme and Spike

Raceme and Spike
The inflorescence is unbranched: the raceme has spikelets with pedicels, the spike has spikelets without pedicels (i.e. spikelets are sessile)

Basic structure of a grass inflorescence
Open panicle.png Open panicle
Inflorescence with branches obvious
Spicate panicle.png Spicate panicle
Inflorescence with branches not obvious
Spatheate inflorescence.png Spatheate inflorescence
The branches of the inflorescence are subtended by spathes (leaf-like bracts)
Digitate inflorescence.png Digitate inflorescence
Inflorescence branches arranged at the top of peduncle like the fingers of the hand

Related information

Grasses © Tothill JC, Hacker JB (1983)

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