The Monocots: Part 2 Commelinid Monocots Spring 2012.
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Transcript of The Monocots: Part 2 Commelinid Monocots Spring 2012.
Phylogeny of Monocot Groups
AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales
Basal“Petaloid”Commelinid
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
Commelinoid Monocot Groups
Order Arecales – PalmsArecaceae (Palmae)
Order Commelinales – Spiderworts, bloodworts, pickerel weeds
Order Zingiberales – Ginger, banana, and allies
Order Poales – Bromeliads, Cat-tails, Rushes, Sedges, and GrassesTyphaceaeJuncaceae CyperaceaePoaceae (Gramineae)
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
Arecaceae
•Unbranched trunks•Big leaves on top!
•Numerous small flowers•Spathes + compound-spicate inflorescence•3 sepals + 3 petals•Superior ovary (carpel fusion varies)•Drupe
Phylogeny of Monocot Groups
AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales
Basal“Petaloid”Commelinid
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
Phylogeny of Monocot Groups
AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales
Basal“Petaloid”Commelinid
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
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
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
Sparganium
This genus is placed inits own family, theSparganiaceae, in yourtext, but it is closelyrelated to Typhaceae andis included in Typhaceaein many treatments.
Typha
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
Juncaceae: Juncus
-cymose inflorescences-leaf sheaths open-leaf blades flat, grooved, or cylindrical
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
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
Cyperaceae
Cyperus
Eleocharis Rhynchospora(note bristle perianth)
Fruit type is the achene: very important inthe taxonomy of the family.
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-ecologically important, especially in wetlands
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
• 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)
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
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 obviously jointed•3
•Closed
•Spikelets
•None or bristles/scalesAchene
•Terete, solid, not obviouslyjointed
•3
•Open
•Cymose
•6 chaffy tepals
•Capsule