Poaceae Gramineae oats rice wheat The most economically

Poaceae (Gramineae)

oats rice wheat The most economically important family of flowering plants. . . sugar cane bamboo

Ceres - the Roman goddess of agriculture

And the fourth largest: 600 Genera /10, 000 species worldwide (ca. 85 genera in New England 55 in Vermont)

Ecology: Occur in practically all habitats, but specialize in dryer sites

Vegetative attributes: • Perennial and sometimes annual herbs • Upright stems (culms) round • Nodes swollen • Internodes hollow • Leaves two-ranked, sheaths split • Ligule often present

Reproductive attributes: • Perianth, if present, of lodicules • Androecium of usually 3 stamens • Ovary superior, of 3 fused carpels • Fruit a caryopsis

Floral Formula:

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

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

glumes ‘Exploded’ spikelet of brome grass ‘Telescoped’ spikelet

Inflorescences Various spike raceme panicle

Character JUNCACEAE (Rushes) CYPERACEAE (Sedges) POACEAE (Grasses) Habitat Mostly wet areas Wetlands and upland woods Various Stems Terete in cross section Internodes solid with large pith Nodes not jointed Triangular (not always visible) Internodes usually solid Nodes not jointed Terete or ellipsoid Internodes hollow (to solid) Nodes jointed Leaves 3 -ranked Blades flat to terete Open sheath 3 -ranked Blades flat 2 -ranked Blades flat Closed sheath Open sheath Basically cymose and often congested Each flower subtended by 2 bracts Spikelets Each flower subtended by one bract (scale) Each flower subtended by 2 bracts (lemma and palea Perianth Usually 6 chaffy tepals Absent or of bristles or scales Reduced to 2 (or 3) scales Fruit Loculicidal capsule Achene Caryopsis (grain) Inflorescence

The major groups: (First a couple of oddballs …)

Spikelets enclosed in a spiny bur. . . Cenchrus longispinus Field sandbur

Spikelets all unisexual, plants monoecious. . . Zizania aquatica Wild rice

Glumes absent; spikelets strongly flattened. . . Leersia oryzoides Rice cutgrass

Magee and Ahles Group 1: Spikelets in two or more rows on one side of the rachis. . . Spartina pectinata Freshwater cordgrass

Magee and Ahles Group 2: Spikelets sessile on the rachis, forming a bilateral spike. . . Elytrigia repens Quackgrass Lolium perenne Ryegrass

Magee and Ahles Group 3: ≥ 2 functional florets/spikelet; glumes shorter than lowest lemma. . . Briza minor Smaller quakinggrass Eragrostis spectabilis Purple lovegrass Bromus inermis Unarmed bromegrass

Magee and Ahles Group 4: ≥ 2 functional florets per spikelet; glumes longer than lowest lemma. . . Avena sativa oats oat spikelet Danthonia spicata Poverty grass

Magee and Ahles Group 5: Functional floret 1/spikelet, this subtended by two sterile florets. . . Phalaris arundinacea Reed canary grass Anthoxanthum odoratum Sweet vernal grass

Magee and Ahles Group 6: Florets in pairs, one sessile and perfect, the other pedicelled and staminate. . . Schizachyrium scoparium Little bluestem Sorghastrum nutans Indian grass

Magee and Ahles Group 7: Spikelets solitary, round in crosssection or dorsiventrally compressed. . . Panicum sp. Panic grass Echinochloa sp. Barnyard grass

Magee and Ahles Group 8: Spikelets solitary, laterally compressed. . . Ammophila breviligulata Beachgrass Oryzopsis racemosa Black-seeded mountain ricegrass Millium effusum Millet