The Monocots: Part 2 Commelinoid Monocots Spring 2011.
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Transcript of The Monocots: Part 2 Commelinoid Monocots Spring 2011.
The Monocots: Part 2Commelinoid Monocots
Spring 2011
Phylogeny of Monocot Groups
AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales
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 - PalmsArecaceae (Palmae)
Order Poales - Grasses - Bromeliads Cat-tails Rushes, Sedges, and GrassesTyphaceaeJuncaceae CyperaceaePoaceae (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
Arecaceae
•Unbranched trunks•Big leaves on top!
•Numerous small flowers•Spathes + compound-spicate inflorescence•3 sepals + 3 petals•Superior ovary (carpel fusion varies)•Drupe
Arecaceae – The Palm Family
Arecaceae – Cocos nucifera
ArecaceaeEconomic plants and products:
Phoenix dactyliferaDates
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)• Family not required; for information only
Bromeliaceae – Ananas comosus
Fruittype?
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
Typhaceae - 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 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
Cyperaceae versus Juncaceae:Field Character
“Sedges have edges…
…and rushes roll.”
Cyperaceae diversity
Cyperaceae
spikelet
flower + subtending bract = floret
Flowers:•Arranged in spikelets•Reduced•Wind-pollinated flowers•Subtended by bract•Reduced/absent perianth
flower
From Zomlefer 1994
Cyperaceae
Cyperus
Eleocharis Rhynchospora(note bristle perianth)
Fruit type is the achene: very important inthe taxonomy of the family.
Cyperaceae
http://waynesword.palomar.edu/termfl3.htm
Cyperaceae: Cyperus
-leaves usually basal-ligules absent-spikelet scales distichous, each subtending a flower-spikelets flattened or cylindrical-flowers bisexual-no perigynium
Cyperaceae: Carex
-presence of the perigynium (a sac-likebract 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: Zea, Triticum, Oryza
Economicimportance Zea mays
Oryza sativaTriticum aestivum
weeds
sugar cane
bamboo
Ecologicalimportance
Poaceae: vegetative structure
ligule
Poaceae: spikelet and flower structure
flower
Images fromGrasses of Iowa
• 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)
Origin of grassesca. 70-80 myain southern-hemisphereforests
early grasses
Panicgrasses(Panicoideae)
Rices(Ehrhartoideae)
Bluegrasses(Pooideae)
Bamboos(Bambusoideae)
Puelioideae
PharoideaeAnomochlooideae
Needlegrasses(Aristidoideae)
Lovegrasses(Chloridoideae)
Micrairoideae
Reeds(Arundinoideae)
Oatgrasses(Danthonioideae)
Major radiationin Oligocene-Miocene epochsinto open habitats
Origin of grassesca. 70-80 myain forests
+
Stamensreduced to 3
C4 photosynthetic pathway(in warm season grasses)is advantageous under higher temperatures, higherlight, and less water
Dispersal!
Poaceae (Gramineae) diversity
Oryza (rice)
-aquatic or wetland herbs-one floret per spikelet-spikelets strongly flattened
Triticum (wheat)-annuals-dense inflorescences-spikelets sessile, one per node-2-9 florets per spikelet
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
For more informationand images:
http://www.eeob.iastate.edu/research/iowagrasses/
The Grasses of Iowa
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 jointed
•3
•Closed
•Spikelets
•None or bristles/scalesAchene
•Terete, solid, not jointed
•3
•Open
•Cymose
•6 chaffy tepals
•Capsule
“Graminoids” - Comparison
Commelinales 5 families, 780 species, widespread in
various habitats
Not required
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 (diploid nutritive tissue derived
from the nucellus)• 8 families and nearly 2000 species Must be ableMust be able
to recognizeto recognizethe order!the order!
Zingiberalesdiversity
MusaceaeMusa