Poaceae

Plant Sex: Plants monoecious, dioecious or flowers bisexual.

Inflorescence: The SPIKELET is the smallest inflorescence unit. Grasses may have one or more florets per spikelet. The spikelets themselves are often grouped into compound inflorescences such as panicles.

Flowers: = FLORETS; may be bisexual, unisexual, or sterile. Perianth absent or modified into LODICULES. Bracts below florets = PALEA, LEMMA,GLUMES. Styles are plumose and extend from the floret. Anthers VERSATILE.

Fruits: CARYOPSIS (= grain): pericarp and testa fused.

Habit: Annual and perennial herbs. May be stoloniferous, rhizomatous, or as turf. Roots are fibrous (all adventitious). Stems (= CULMS) terete (round in x.s.). Nodes are hollow.

Leaves: 2-ranked, lamina (blade) flat but not channeled, with sheathing leaf bases. A LIGULE may be present at junction of sheath and lamina. The ligule in Arundinaria is filamentous whereas in Bromus it is membranous.

Examples:

Food (humans & animals)

Avena

A. sativa (oats). Oat field. Oats on Wikipedia.

Oryza

O. sativa (rice). Rice harvest in Asia. Rice on Wikipedia.

Saccharum

S. officinale (sugar cane). Field showing young crop of sugarcane. Mature crop. Munching on sugar cane in Papua New Guinea.

Sorghum

S. bicolor (sorghum or milo). Field of milo. Closer view of sorghum grains.

Triticum

T. aestivum (wheat). Wheat field near Carbondale. Inflorescences. Spikelets in fruit.

Zea

Z. mays (maize, corn). Field of maize. Close-up of staminate inflorescence. Carpellate inflorescence (young ear of corn) with styles (silks). Section of carpellate inflorescence showing styles (silks). Close-up of carpellate inflorescence. Sweet corn ear. Mature field corn. Mature ear of corn with husks opened up. Ears of corn showing color variation. Indian corn.
Z. mexicana (teosinte). Staminate inflorescence. Carpellate inflorescences. Changes from teosinte to maize.

Turf [Lawn grass on Wikipedia]

Festuca

F. elatior (fescue). Spikelet.

Poa

P. pratensis (bluegrass). Inflorescence. Closer view of spikelets. One spikelet. Dissected spikelet. Dissected floret. Versatile anthers.

Prairie components

Andropogon

A. gerardii (big bluestem). Habit of plants. Inflorescence structure, labeled. Close-up of inflorescences showing stamens (with versatile anthers) and styles. Big bluestem on Illinois wildflowers webpage.

Sorghastrum

S. nutans (Indian grass). Inflorescence. Indian grass on Illinois wildflowers webpage.

Stipa

S. spartea (porcupine grass). Habit of plants. Self-planting fruits.

Weeds

Bromus

B. tectorum (bromegrass, downy chess). Various photos. The perennial bromegrasses are important forage crops whereas the annual species are weeds introduced from Europe.

Cenchrus

C. longispinus (sandspur). Inflorescence showing spiny spikelets. Sandspur on Illinois wildflowers webpage.
C. pauciflorus. Infructescence of the field sandbur.

Dactylus

D. glomerata (orchard grass). Inflorescence. Close-up of spikelets. Orchard grass on Illinois wildflowers webpage.

Digitaria

D. sanguinalis (common crab grass). Inflorescence. Crab grass on Illinois wildflowers webpage.

Echinochloa

E. crus-galli (barnyard grass). Spikelets. Barnyard grass on Illinois wildflowers webpage.

Setaria

S. faberi (giant foxtail grass). Giant foxtail grass on Illinois wildflowers webpage.
S. viridis. Spikelets.

Sorghum

S. halepense (Johnsongrass). Habit of the grass. Leaves; note the red color on some, from Johnsongrass mosaic virus. This also forms maize dwarf mosaic virus and maize chlorotic dwarf diseases. Rhizome and stem with prop roots. Spikelets. Johnson grass on Illinois wildflowers webpage.

Construction material

Bambusa

B. vulgaris (bamboo). Habit of plants.
B. blumeana. Bamboo logs cut and ready haul away in the Philippines.

SIUC / College of Science / Elements of Plant Systematics
URL: http://www.plantbiology.siu.edu/PLB304/Lecture26Poales/Poaceae.html
Last updated 01-May-11 / dln