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The Monocots: Part 2 Commelinid Monocots Spring 2012
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Phylogeny of Monocot Groups Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales Basal “Petaloid” Commelinid
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Fig. 7.17
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Commelinid characters Special type of epicuticular wax Starchy pollen UV-fluorescent compounds in the cell walls Starchy endosperm (except in the palms) Lots of molecular support
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Fig. 7.45
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Commelinoid Monocot Groups Order Arecales – Palms Arecaceae (Palmae) Order Commelinales – Spiderworts, bloodworts, pickerel weeds Order Zingiberales – Ginger, banana, and allies Order Poales – Bromeliads, Cat-tails, Rushes, Sedges, and Grasses Typhaceae Juncaceae Cyperaceae Poaceae (Gramineae)
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Commelinoid Monocots: Arecales: Arecaeae (Palmae) Widespread throughout tropical and warm temperate regions “Trees” or “shrubs”, typically unbranched Diversity: ca. 2,000 in 190 genera Flowers: usually sessile, in compound-spicate inflorescences, these subtended by a bract (spathe); ovule 1 per locule Significant features: Leaves alternate or spiral, blades plicate, splitting in a pinnate or palmate manner Special uses: coconut (Cocos nucifera), date (Phoenix dactylifera), rattan (Calamus), oils and waxes, ornamentals Family not required
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Arecaceae Unbranched trunks Big leaves on top! Numerous small flowers Spathes + compound-spicate inflorescence 3 sepals + 3 petals Superior ovary (carpel fusion varies) Drupe
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Arecaceae – Cocos nucifera
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Arecaceae Economic plants and products: Cocos nucifera Coconut, oil
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Arecaceae Economic plants and products: Phoenix dactylifera Dates
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Phylogeny of Monocot Groups Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales Basal “Petaloid” Commelinid
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Commelinales 5 families, ca. 780 species, widespread in various habitats Not required
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Commelinid Monocots: Zingiberales Large herbs with vessels more or less limited to the roots Silica cells present in the bundle sheaths Leaves clearly differentiated into a petiole and blade Leaf blade with penni-parallel venation, often tearing between the second-order veins Leaf blade rolled into a tube in bud Petiole with enlarged air canals Flowers bilateral (or irregular) Pollen lacking an exine Ovary inferior Seeds arillate and with perisperm (diploid nutritive tissue derived from the nucellus) 8 families and nearly 2000 species
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Fig. 7.55
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Zingiberales diversity
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Fig. 7.56
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Musaceae Musa
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Phylogeny of Monocot Groups Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales Basal “Petaloid” Commelinid
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Characters of Poales Silica bodies (in silica cells) in the epidermis Styles strongly branched Loss of raphide (needle-like) crystals in most Much molecular support for monophyly Wind pollination has evolved several times independently within the order Ecologically very important
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Fig. 7.63
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Commelinid Monocots—Poales: Bromeliaceae (The Pineapple/Bromeliad Family) Tropical to temperate regions of the Americas Predominantly epiphytic herbs (“tank” plants) Diversity: ca. 2,400 species in 59 genera Flowers: radial, perianth differentiated into calyx and corolla, borne in axils of often brightly colored bracts; inflorescences spicate or paniculate; stigmas 3, usually twisted; seeds often winged or with tufts of hair Significant features: leaves with water absorbing peltate (or stellate) scales Special uses: pineapple (Ananas) Family not required
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Bromeliaceae: Tillandsia (Spanish moss)
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Bromeliaceae – Ananas comosus Fruit type?
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Commelinoid Monocots—Poales: Typhaceae (The Cattail Family) Widely distributed, especially in Northern Hemisphere Emergent aquatic rhizomatous herbs Diversity: 8-13 species in 1 genus Flowers: small, unisexual; separated spatially on dense, compact spicate inflorescences; placentation apical Significant features: rhizomatous; long slender leaves; characteristic inflorescence Special uses: ornamental aquatics Required taxa: Typha
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Sparganium This genus is placed in its own family, the Sparganiaceae, in your text, but it is closely related to Typhaceae and is included in Typhaceae in many treatments. Typha
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Commelinid Monocots—Poales: Juncaceae (The Rush Family) Worldwide, mostly temperate regions; wet or damp habitats Rhizomatous herbs, stems round and solid Diversity: 350 species in 6 genera Flowers: tepals 6, distinct; carpels 3 in superior ovary; stamens 6; fruit a loculicidal capsule Significant features: leaves 3-ranked, sheaths usually open Special uses: leaves used to weave rush baskets; some ornamentals Required taxa: Juncus
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Juncaceae Juncus Distichia
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Juncaceae: Juncus -cymose inflorescences -leaf sheaths open -leaf blades flat, grooved, or cylindrical
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Commelinid Monocots—Poales: Cyperaceae (The Sedge Family) Worldwide, usually in damp or semi-aquatic sites Rhizomatous herbs, stems usually triangular in cross section and solid Diversity: 5,000 species in 104 genera Flowers: with 1 subtending bract; tepals absent or reduced to 3-6 scales or hairs; stamens 1-3; carpels 2-3 in superior ovary; fruit an achene (nutlet) Significant features: Inflorescence a complex group of spikelets; leaf sheaths closed, ligule lacking; silica bodies conical Special uses: Papyrus used originally for paper; “water chestnuts” and a few other rhizomes edible, leaves used for weaving; some ornamentals. Required taxa: Carex, Cyperus
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Cyperaceae versus Juncaceae: Field Character “Sedges have edges… …and rushes roll.”
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Fig. 7.65 Fig. 7.66D
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Cyperaceae Sedge spikelet flower + subtending bract = floret Flowers: Arranged in spikelets Reduced Wind-pollinated flowers Subtended by bract Reduced/absent perianth flower From Zomlefer 1994
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Cyperaceae Cyperus Eleocharis Rhynchospora (note bristle perianth) Fruit type is the achene: very important in the taxonomy of the family.
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Cyperaceae http://waynesword.palomar.edu/termfl3.htm
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Cyperaceae: Cyperus -leaves usually basal -ligules absent -spikelet scales distichous, each subtending a flower -spikelets flattened or cylindrical -flowers bisexual -no perigynium
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Cyperaceae: Carex -presence of the perigynium (a sac-like bract surrounding the female flower) in addition to the subtending bract -leaves usually with a ligule -ecologically important, especially in wetlands
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Cyperaceae: Carex
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Commelinid Monocots—Poales: Poaceae (Gramineae) (The Grass Family) Cosmopolitan Primarily herbs, often rhizomatous; “trees” in most bamboos; stems are called culms, hollow or solid Diversity: >10,000 species in ca. 650 genera Flowers: small petals reduced to lodicules; each flower enclosed by two bracts (lemma and palea) = floret; stamens typically 3; carpels 3, but appearing as 2; fruit a caryopsis Significant features: 1-many florets aggregated into spikelets, each with usually 2 empty bracts (glumes) at the base; leaf with a ligule Special uses: many – grains, turf, fodder/forage, structural uses (e.g., bamboo). Required taxa: family only
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Economic importance Zea mays Oryza sativa Triticum aestivum weeds sugar cane bamboo
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Ecological importance
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Poaceae: vegetative structure ligule
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Poaceae: spikelet and flower structure flower Images from Grasses of Iowa
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The fruit wall (pericarp) is completely fused to the seed coat. Endosperm (3N; triploid) contains the bulk of starch storage in the seed. The embryo is a pre-formed grass plant, with apical meristems (for both shoot and root) and protective organs (coleoptile and coleorhiza) which emerge first during germination. Anatomy of the Caryopsis (Grain)
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Poaceae: caryopsis (grain) Setaria foxtail Zea mays corn or maize
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Origin of grasses ca. 70-80 mya in southern- hemisphere forests early grasses
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Panicgrasses (Panicoideae) Rices (Ehrhartoideae) Bluegrasses (Pooideae) Bamboos (Bambusoideae) Puelioideae Pharoideae Anomochlooideae Needlegrasses (Aristidoideae) Lovegrasses (Chloridoideae) Micrairoideae Reeds (Arundinoideae) Oatgrasses (Danthonioideae) Major radiation in Oligocene- Miocene epochs into open habitats Origin of grasses ca. 70-80 mya in forests + Stamens reduced to 3
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C 4 photosynthetic pathway (in warm season grasses) is advantageous under higher temperatures, higher light, and less water
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Dispersal!
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Poaceae: Bambusoideae
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Oryza (rice) -aquatic or wetland herbs -one floret per spikelet -spikelets strongly flattened
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Triticum (wheat) -annuals -dense inflorescences -spikelets sessile, one per node -2-9 florets per spikelet
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Zea (maize or corn) -male and female spikelets usually on separate inflorescences -female inflorescences axillary, enclosed in 1 or more sheaths (husks), one sessile spikelet per node -male inflorescences terminal, with paired spikelets
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For more information and images: http://www.eeob.iastate.edu/research/iowagrasses/ The Grasses of Iowa
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Grasses, Sedge, Rushes ! Stem terete, hollow, or solid, jointed Leaf ranks 2 Leaf sheath Open, ligule Inflor: Spikelets Perianth: Lodicules Fruit: Caryopsis Triangular, solid, not obviously jointed 3 Closed Spikelets None or bristles/scales Achene Terete, solid, not obviously jointed 3 Open Cymose 6 chaffy tepals Capsule
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“Graminoids” - Comparison
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Next time: The “Basal” Eudicots…
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