Poaceae(Gramineae)

Order Poales

Angiosperm Phylogeny Group

Poaceae is by far the most economically important family of angiosperms.

Avena (oats) Oryza (rice) Triticum (wheat)

Saccharum (sugarcane)

Bambusa (bamboo)Zea (corn)

Staple cereals: Oryza (rice), Triticum (wheat), Avena (oats), Zea (corn), Secale (rye)

Sugar: Saccharum (sugarcane), Sorghum

Alcohol: Oryza (sake), Saccharum (rum), Hordeum (beer), Secale and Zea (whiskey)

Forage and fodder, paper and building materials (e.g. bamboo), essential oils (e.g. lemongrass), ornamental and turf grasses.

Other stuff:

Poaceae is the most economically important group of angiosperms.

•13 subfamilies

•668 genera

•10,035 species

•85 genera in New England

•55 in Vermont

Poaceae family diversity:

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Poaceae distribution:

Cosmopolitan distribution,specializing in drier sites.

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Vegetative characters:

• Perennial and sometimes annual herbs

• Upright stems (culms) round

• Nodes swollen

• Internodes hollow

• Leaves alternate, simple, entire, with parallel venation. Sheathing at base, sheath open.

• Ligule often present

• Perianth, if present, of lodicules

• Androecium of usually 3 stamens

• Ovary superior, of 3 fused carpels

• Fruit a caryopsis

Reproductive characters:

Floral Formula:

Reproductive characters:

Florets are enclosed by two bracts, the palea and the lemma

palea

lemma

rachilla

Reproductive characters:

Reproductive characters:

Florets are arranged in spikelets, these subtended by a pair of glumes

glumes

Reproductive characters:

glumes

‘Telescoped’ spikelet‘Exploded’ spikelet of brome grass

Inflorescence types vary:

spike raceme panicle

Caryopsis (grain)

AcheneLoculicidal capsule

Fruit

Reduced to 2 (or 3) scales

Absent or of bristles or scales

Usually 6 chaffy tepals

Perianth

Spikelets

Each flower subtended by 2 bracts (lemma and palea

Spikelets

Each flower subtended by one bract (scale)

Basically cymose and often congestedEach flower subtended by 2 bracts

Inflorescence

2-rankedBlades flat

Open sheath

3-rankedBlades flat

Closed sheath

3-rankedBlades flat to tereteOpen sheath

Leaves

Terete or ellipsoidInternodes hollow (to solid)Nodes jointed

Triangular (not always visible)Internodes usually solidNodes not jointed

Terete in cross sectionInternodes solid with large pithNodes not jointed

Stems

VariousWetlands and upland woods

Mostly wet areasHabitat

POACEAE (Grasses)

CYPERACEAE (Sedges)

JUNCACEAE (Rushes)

Character