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The Monocots: Part 2 Commelinoid Monocots. Spring 2010. Phylogeny of Monocot Groups. Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales. Basal “ Petaloid ” Commelinoid. Commelinoid characters.
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The Monocots: Part 2Commelinoid Monocots Spring 2010
Phylogeny of Monocot Groups Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales Basal “Petaloid” Commelinoid
Commelinoid 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
Commelinoid Monocot Groups Order Arecales - Palms Arecaceae (Palmae) Order Poales - Grasses - Bromeliads Cat-tails Rushes, Sedges, and Grasses Bromeliaceae Typhaceae Juncaceae Cyperaceae Poaceae (Gramineae) Order Zingiberales – Ginger, banana, and allies (no required families)
Commelinoid Monocots:Arecales: Arecaeae (Palmae) • Widespread throughout tropical and warm temperate regions • “Trees” or “shrubs”, typically unbranched • Diversity: ca. 2,780 in 200 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 • Required taxa: *family only * Change from lab manual
Arecaceae • Numerous small flowers • Spathes + compound-spicate inflorescence • 3 sepals + 3 petals • Superior ovary (carpel fusion varies) • Drupe • Unbranchedtrunks • Big leaves on top!
Arecaceae Economic plants and products: Phoenix dactylifera Dates
Characters of Poales • Silica bodies (in silica cells) in the epidermis • Styles strongly branched • Loss of raphide (needle-like) crystals • Much molecular support for monophyly • Wind pollination has evolved several times independently within the order • Ecologically very important
Commelinoid Monocots—Poales:Bromeliaceae(The Pineapple/Bromeliad Family) • Tropical to temperate regions of the Americas • Predominantly epiphytic herbs (“tank” plants) • Diversity: ca. 1,520 species in 51 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) • Required taxa: *Tillandsia (Spanish moss) *change from lab manual
Bromeliaceae – Ananascomosus Fruit type?
Commelinoid Monocots—Poales:Typhaceae(The Cattail Family) • Widely distributed, especially in Northern Hemisphere • Aquatic & wetland rhizomatous herbs • Diversity: 28 species in 2 genera • Flowers: small, unisexual; separated spatially on dense, compact spicate or globose-clustered inflorescences; placentation apical • Significant features: rhizomatous; long slender leaves; characteristic inflorescence • Special uses: ornamental aquatics • Required taxa: Typha
Commelinoid Monocots—Poales:Juncaceae(The Rush Family) • Worldwide, mostly temperate regions; wet or damp habitats • Rhizomatous herbs, stems round and solid • Diversity: 400 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
Juncaceae: Juncus -cymose inflorescences -leaf sheaths open -leaf blades flat, grooved, or cylindrical
Commelinoid Monocots—Poales:Cyperaceae(The Sedge Family) • Worldwide, usually in damp or semi-aquatic sites • Rhizomatous herbs, stems usually triangular in cross section • Diversity: 4,500 species in 104 genera • Flowers: with 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
Cyperaceae versus Juncaceae:Field Character “Sedges have edges… …and rushes roll.”
Flowers: • Arranged in spikelets • Reduced • Wind-pollinated flowers • Subtended by bract • Reduced/absent perianth Cyperaceae flower + subtending bract = floret flower spikelet
Cyperaceae Fruit type is the achene: very important in the taxonomy of the family. Eleocharis Rhynchospora (note bristle perianth) Cyperus
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
Commelinoid Monocots—Poales:Poaceae (Gramineae)(The Grass Family) • Cosmopolitan • Primarily herbs, often rhizomatous; “trees” in most bamboos; stems are called culms • Diversity: 10,000 species in ca. 650 genera • Flowers: small, perianth parts 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: *Poa, *Andropogon *change from lab manual
bamboo Economic importance sugar cane Zea mays weeds Oryza sativa Triticum aestivum
Ecological importance
Anatomy of the Caryopsis (Grain) • 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.
early grasses Origin of grasses ca. 70-80 mya in southern- hemisphere forests
Anomochlooideae Pharoideae Puelioideae Bamboos (Bambusoideae) Origin of grasses ca. 70-80 mya in forests Bluegrasses (Pooideae) Rices (Ehrhartoideae) Panicgrasses (Panicoideae) Major radiation in Oligocene- Miocene epochs into open habitats Needlegrasses (Aristidoideae) Lovegrasses (Chloridoideae) + Micrairoideae Stamens reduced to 3 Reeds (Arundinoideae) Oatgrasses (Danthonioideae)
C4 photosynthetic pathway (in warm season grasses) is advantageous under higher temperatures, higher light, and less water
Poaceae: Poa -cool season -leaf tip boat-shaped -inflorescence branched from a main axis -spikelets solitary -glumes papery -florets 3-several, often with a cottony web at the base
Poaceae: Andropogon -warm season -leaf midrib whitish, prominent -2-many branches per inflorescence, often digitate -spikelets paired -glumes tough, leathery
For more informationand images:http://www.eeob.iastate.edu/research/iowagrasses/The Grasses of Iowa
Grasses, Sedge, Rushes! • Terete, solid, • not jointed • 3 • Open • Cymose • 6 chaffy tepals • Capsule • Triangular, solid, not jointed • 3 • Closed • Spikelets • None or bristles/scales • Achene • Stem terete, hollow, • or solid, jointed • Leaf ranks 2 • Leaf sheath Open, • ligule • Inflor: Spikelets • Perianth: Lodicules • Fruit: Caryopsis
Commelinales 5 families, 780 species, widespread in various habitats
Commelinoid 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 pinnate 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 • 8 families and nearly 2000 species Must be able to recognize the order!