Transcript Systematic Implications of DNA variation in subfamily

The Monocots: Part 2
Commelinoid Monocots
Spring 2011
Phylogeny of Monocot Groups
Basal
“Petaloid”
Commelinoid
Acorales
Alismatales
Asparagales
Liliales
Dioscoreales
Pandanales
Arecales
Poales
Commelinales
Zingiberales
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
Typhaceae
Juncaceae
Cyperaceae
Poaceae (Gramineae)
Order Zingiberales – Ginger,
banana, and allies (no required
families)
Commelinoid Monocots:
Arecales: Arecaeae (Palmae)
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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
•Numerous small
flowers
•Spathes +
compound-spicate
inflorescence
•3 sepals + 3 petals
•Superior ovary
(carpel fusion
varies)
•Drupe
•Unbranched
trunks
•Big leaves
on top!
Arecaceae – The Palm Family
Arecaceae – Cocos nucifera
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
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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
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
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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)
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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
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(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
Flowers:
•Arranged in spikelets
•Reduced
•Wind-pollinated flowers
•Subtended by bract
•Reduced/absent perianth
spikelet
flower +
subtending
bract = floret
Cyperaceae
flower
From Zomlefer 1994
Cyperaceae
Fruit type is the achene: very important in
the taxonomy of the family.
Cyperus
Eleocharis
Rhynchospora
(note bristle perianth)
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-like
bract surrounding the female flower) in
addition to the subtending bract
-leaves usually with a ligule
Commelinoid Monocots—Poales:
Poaceae (Gramineae)
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(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
bamboo
sugar cane
weeds
Economic
importance
Zea mays
Oryza sativa
Triticum aestivum
Ecological
importance
Poaceae:
vegetative
structure
ligule
Poaceae: spikelet and flower structure
flower
Images from
Grasses of Iowa
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 southernhemisphere
forests
Anomochlooideae
Pharoideae
Puelioideae
Origin of
grasses
ca. 70-80 mya
in forests
Bamboos
(Bambusoideae)
Bluegrasses
(Pooideae)
Rices
(Ehrhartoideae)
Panicgrasses
Major radiation
in OligoceneMiocene epochs
into open habitats
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(Panicoideae)
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
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 information
and images:
http://www.eeob.iastate.edu/research/iowagrasses/
The Grasses of Iowa
Grasses,
Sedge,
Rushes!
•Stem terete, hollow,
or solid, jointed
•Triangular,
solid, not
jointed
•Terete, solid,
not jointed
•Leaf ranks 2
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•Leaf sheath Open,
ligule
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•Open
•Inflor: Spikelets
•Spikelets
•Cymose
•Perianth: Lodicules
•None or
bristles/scales
Achene
•6 chaffy tepals
•Fruit: Caryopsis
•Capsule
“Graminoids” - Comparison
Commelinales
5 families, 780 species, widespread in
various habitats
Not required
Commelinoid Monocots:
Zingiberales
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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 able
to recognize
the order!
Zingiberales
diversity
Musaceae
Musa