Wisconsin flora “wordle” Poaceae - the grasses 321
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• the second large independent shift to reduced flowers and spikelets for wind pollination • 4th largest family - 620 genera, 10,000 species • most important family (ethnobotanically) 283
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grasses you collected! Picture key to grasses!
Setaria spp. – Setaria spp. – foxtail foxtail Andropogon gerardii – Schizachyrium scoparium– Andropogon gerardii – Schizachyrium scoparium– big bluestem little bluestem big bluestem little bluestem Grasses of Iowa www.eeob.iastate.edu/research/iowagrasses
Field Guide to Wisconsin Grasses – book in lab Sorghastrum nutans – Phalaris arundinacea – Bromus inermis– Indian grass reed canary grass smooth brome
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1 Poales III: wind pollinated families Poales III: wind pollinated families
• showy flowers, Evolutionary trends: • showy flowers, insect or bird insect or bird pollinated • nectar to pollen gathering to pollinated wind pollination • +/- reduced • reduced flowers - loss of • +/- reduced flowers, insect or perianth flowers, insect or wind pollinated wind pollinated • unisexuality sometimes • bracts become important • reduced • reduced flowers, wind • flowers to florets in spikelets flowers, wind pollinated pollinated
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Poaceae - grasses Poaceae - grasses Poaceae related to more typical, although reduced, flowered Poaceae related to more typical, although reduced, flowered graminoid monocots with 6 tepals – Southern Hemisphere! graminoid monocots with 6 tepals – Southern Hemisphere!
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2 Poaceae - grasses Poaceae - grasses Poaceae related to more typical, although reduced, flowered graminoid monocots with 6 tepals – Southern Hemisphere! What has driven this large and successful adaptive • bracted radiation? • 6 tepals 5076 species • mixed male & female 4 species 12 species flowers 12 species • achene
female 5423 species male
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Poaceae - grasses Poaceae - grasses
node Vegetative features • first diversified ca. 70 mya in late • jointed, hollow, Cretaceous – tropical circular stems forest understories (culms) • major radiations • leaves 2-ranked or during formation of spiralled grasslands in mid Tertiary • blade, sheath, and ligule • shift to grasslands • intercalary basis for adaptive meristem above radiation? blade ligule nodes sheath Strömberg et al. PNAS 2005;102:11980-11984
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3 Evolution of C4 Poaceae - grasses photosynthesis across angiosperms Adaptive features
• intercalary Poaceae meristem - grazing & fire response
• silica in stems
• C4 photo- synthesis in arid “grasslands” • C4 photosynthesis evolved 62 times in angiosperms Nebraska grassland 25 mya
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Poaceae - grasses Poaceae - grasses
• has C4 photo- • has whole genome synthesis driven doubling been a key speciation? innovation for grass diversification? 5076 species 5076 species 4 species 4 species 12 species • C4 photosynthesis 12 species 12 species 12 species evolved 62 times in • WGD at base of angiosperms PACMAD and BOP clades 5423 species • 24 times just in 5423 species grasses • 11,000 vs. 28 spp.
• all in PACMAD clade
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4 Poaceae - grasses Poaceae - grasses
The main unit of the Defining feature of inflorescence is the spikelet grasses are the which is composed of 2 glumes (spikelet bracts) and 1 spikelet and its florets or more florets
Brome Oats
spikelet glumes
florets Dactylis glomerata Orchard grass
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Poaceae - grasses Poaceae - grasses
Each floret is surrounded by This spikelet with two glumes two floret bracts - the outer has two florets each with two lemma and the inner palea floret bracts - the outer lemma (usually not seen until and the inner palea anthesis - when florets open)
Brome Oats
glumes
lemma lemma
palea palea Dactylis glomerata Orchard grass
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5 Poaceae - grasses Poaceae - grasses
Although considerable variation occurs in florets (among species or within a spikelet), most of our species have the following floret anthesis – expose structure: anthers & styles fungal endophytes – preventing spores • Perianth represented by 2 lodicules entering fruit?
What is function of lodicules? What is function of lodicules?
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Poaceae - grasses Poaceae - grasses
• fungal endophytes • fungal endophytes (ascomycetes) produce (ascomycetes) produce physiologically active physiologically active alkaloids alkaloids
• anti-herbivory defense against grazing mammals (defensive mutualism)?
Nebraska grassland 25 mya Nebraska grassland 25 mya
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6 Poaceae - grasses Poaceae - grasses
Although considerable variation occurs in florets (among species or within a spikelet), most of our species have the following floret structure: bisexual floret
• phylogenetic analysis of bamboos turned out to be phylogeny of endophytic fungi! • Perianth represented by 2 lodicules • Stamens 3 • Superior gynoecium of 2 fused carpels Lynn Clark • One ovuled fruits called a grain or caryopsis = seed fused to ovary wall What parts homologous to other flowers? Jonathan Wendel
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Poaceae - grasses Poaceae - grasses
Although considerable variation occurs in florets (among species • lodicules = petals or within a spikelet), most of our • palea/lemma = sepals species have the following floret structure:
Toby Kellogg – Missouri Bot Gard
• Perianth represented by 2 lodicules • Stamens 3 • Superior gynoecium of 2 fused carpels • One ovuled fruits called a grain or caryopsis = seed fused to ovary wall What parts homologous to other flowers? What parts homologous to other flowers?
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7 Poaceae - grasses Poaceae - grasses
South American origin!
BOP Grass
phylogenetics PACMAD
Basal grasses
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Poaceae - grasses Poaceae - grasses
Anomochloa marantoidea Streptochaete
4 stamens!
Subfamily Anomochlooideae (no spikelets, lodicules)
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8 Poaceae - grasses Poaceae - grasses
Subfamily Pharoideae (herbaceous bamboos)
Grass phylogenetics
Pharus Core grasses
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Poaceae - grasses Poaceae - grasses
Bambusa
Subfamily Ehrhartoideae (stamens 6, but 2 styles)
Subfamily Bambusoideae Oryza sativa - rice (6 stamens, 3 lodicules, 3 stigmas) 2nd most important crop plant in the world Ochlandra
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9 Poaceae - grasses Poaceae - grasses
Subfamily Ehrhartoideae Poa annua - bluegrass (stamens 6, but 2 styles) Subfamily Pooideae Ziziana aquatica - wild rice (Spikelets with more than one grain forming floret; Important native American food; Lemma with 5 nerves) unisexual spikelets Poa pratensis - Kentucky bluegrass
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Poaceae - grasses Poaceae - grasses
Dactylis glomerata - orchard grass
Elymus hystrix bottlebrush
Bromus inermis - bromegrass Avena sativa - oats
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10 Poaceae - grasses Poaceae - grasses Subfamily Arundinoideae (large inflorescences)
Phalaris arundinacea Reed canary grass
Calamagrostis canadensis - bluejoint grass Phragmites australis - common reed Circumboreal species; non- native populations have become invasive and displaced native populations
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Poaceae - grasses Poaceae - grasses Subfamily Chloridoideae (Spikelets arranged often one-sided)
Spartina pectinata Prairie cord grass
Cortaderia - plume grasses from Bouteloua curtipendula pampas Sideoats grass
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11 Poaceae - grasses Poaceae - grasses Subfamily Panicoideae (2 florets, bottom reduced, sterile)
Digitaria - crabgrass
Panicum virgatum - switchgrass Dichanthelium sp. - panic grass Setaria - foxtail
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Poaceae - grasses Poaceae - grasses
Andropogon gerardii - big bluestem
Saccharum - Sorghum - sugarcane sorghum 47 48
12 Poaceae - grasses Poaceae - grasses
The origin of maize from teosinte wild relatives in Mexico involved few genes
Female spikelets condensed into Male spikelets in cob or spike panicle or tassel Zea mays - maize Tripsacum - teosinte John Doebley Zea mays - maize 49 50
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