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Poaceae (Gramineae)

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 and 55 in Vermont).

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Poaceae (Gramineae)

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  1. Poaceae (Gramineae)

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

  3. Ceres - the Roman goddess of agriculture

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

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

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

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

  8. Floral Formula:

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

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

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

  12. Inflorescences Various raceme panicle spike

  13. 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 Closed sheath 2-ranked Blades flat Open sheath Inflorescence Basically cymose and often congested Each flower subtended by 2 bracts Spikelets Each flower subtended by one bract (scale) Spikelets 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)

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

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

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

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

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

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

  20. 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

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

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

  23. 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

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

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

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