Poaceae (Gramineae)
The most economically important family of flowering plants ... 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 and 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 rachilla
Florets are arranged in spikelets, these subtended by a pair of glumes
‘Telescoped’ spikelet ‘Exploded’ spikelet of brome grass glumes ‘Telescoped’ spikelet ‘Exploded’ spikelet of brome grass
Inflorescences Various raceme panicle spike
Caryopsis (grain) Achene Loculicidal 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 Each flower subtended by one bract (scale) Basically cymose and often congested Each flower subtended by 2 bracts Inflorescence 2-ranked Blades flat Open sheath 3-ranked Closed sheath Blades flat to terete Leaves Terete or ellipsoid Internodes hollow (to solid) Nodes jointed Triangular (not always visible) Internodes usually solid Nodes not jointed Terete in cross section Internodes solid with large pith Stems Various Wetlands and upland woods Mostly wet areas Habitat POACEAE (Grasses) CYPERACEAE (Sedges) JUNCACEAE (Rushes) Character
(First a couple of oddballs …) 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
Spikelets in two or more rows on one side of the rachis ... Magee and Ahles Group 1: Spikelets in two or more rows on one side of the rachis ... Spartina pectinata Freshwater cordgrass
Spikelets sessile on the rachis, forming a bilateral spike ... Magee and Ahles Group 2: Spikelets sessile on the rachis, forming a bilateral spike ... Elytrigia repens Quackgrass Lolium perenne Ryegrass
≥2 functional florets/spikelet; glumes shorter than lowest lemma ... Magee and Ahles Group 3: ≥2 functional florets/spikelet; glumes shorter than lowest lemma ... Bromus inermis Unarmed bromegrass Briza minor Smaller quakinggrass Eragrostis spectabilis Purple lovegrass
Magee and Ahles Group 4: ≥2 functional florets per spikelet; glumes longer than lowest lemma ... oat spikelet Danthonia spicata Poverty grass Avena sativa oats
Anthoxanthum odoratum 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
Schizachyrium scoparium 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 cross- section or dorsiventrally compressed ... Panicum sp. Panic grass Echinochloa sp. Barnyard grass
Spikelets solitary, laterally compressed ... Magee and Ahles Group 8: Spikelets solitary, laterally compressed ... Ammophila breviligulata Beachgrass Oryzopsis racemosa Black-seeded mountain ricegrass Millium effusum Millet