The Rest of the Monocots

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The Rest of the Monocots
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Monocots Taxa covered Commelinoid
Monocots Order Arecales, family Arecaceae
Order Commelinales, families Commelinaceae,
Pontederiaceae Order Poales,
family Bromeliaceae, Typhaceae, Eriocaulaceae,
Xyridaceae, Juncaceae, Cyperaceae, Poaceae
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Commelinoid Monocots More than half of the
species in this group belong to the family
Poaceae (grasses). Flowers of species in this
group tend to be pollinated by pollen-gathering be
es or by wind. Floral reduction associated
with adaptation to wind pollination is
prevalent. Common characteristics - loss of
floral parts for wind pollination - increasing
importance of the spikelet as an inflorescence
type - development of achene or caryopsis as
fruits Starchy endosperm may be a synapomorphy
for this group. Only family without starchy
endosperm is Arecaceae (palms).
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Monocots Commelinoid Monocots Order
Arecales Family Arecaceae (palm
family) Diagnostic Characters
Vegetative Habit Trees or shrubs with
unbranched or rarely branched trunks only
monocots that are trees without secondary
growth. Leaves Leaves more or less palmately
lobed or split, and plicate (folded).
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Serenoa repens (native to southeastern U.S.)
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Species to Review on CD-ROM No particular
species, but look at general images of palms
be able to recognize members of this family.
Cocos nucifera
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Monocots Commelinoid Monocots Order
Commelinales Family Commelinaceae (spiderwort
family) Diagnostic Characters
Vegetative Habit Herbs, often succulent and
with swollen nodes. Leaves alternate,
scattered along the stem Leaves have a closed
basal sheath Floral - Flowers usually
bisexual, actinomorphic to zygomorphic -
Perianth differentiated into calyx and corolla -
3 petals, with one petal sometimes differently
colored and/or reduced - Inflorescences
terminal or axillary cymes, often subtended by a
folded, leafy bract Fruit- usually a capsule
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Floral formula , K3, C 3 , A3 or 6, G 3
Tradescantia ohioensis (native to this area)
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Commelina erecta (native to this area)
Species to Review on CD-ROM Tradescantia
ohioensis Commelina erecta
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Monocots Commelinoid Monocots Order
Commelinales Family Pontederiaceae (water
hyacinth family) Diagnostic Characters
Vegetative Habit Rhizomatous, herbaceous,
floating to emergent aquatic
plants. Leaves Usually alternate, along stem
or basal, simple, entire, sheathing at base
Floral - Flowers bisexual, actinomorphic to
zygomorphic, often tristylous - Inflorescences
often raceme-like or spike-like - 6 showy tepals
are variably connate - Filaments of stamens are
adnate to the perianth tube - Heterostyly (p. 72
in Judd et al. also see Figure 9.28 on p. 284)
Fruit - capsule or nut - surrounded by
persistent basal portion of perianth tube
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Pontederia cordata (native to this area)
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Floral formula or X, T -6- , A6, G
3 Species to Review on CD-ROM Pontederia
cordata
Inflorescence of Pontederia cordata
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Monocots Commelinoid Monocots Order Poales Family
Bromeliaceae (pineapple family) Diagnostic
Characters Vegetative Habit Herbs,
usually epiphytic Leaves have water-absorbing
scales Leaves often form a tank-like basal
rosette that holds water, and serves as a
microhabitat for frogs, mosquitoes, and
other organisms.
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Bromeliad with leaves forming water-holding tank
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Species to Review on CD-ROM No particular
species, but look at general images, and be able
to recognize members of this family.
Ananas comosus
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Monocots Commelinoid Monocots Order Poales Family
Typhaceae (cattail family) Diagnostic
Characters Vegetative Habit Rhizomatous
herb in wetland habitats. Leaves alternate,
2-ranked, simple, linear, entire, often spongy
with air canals Floral - Inflorescence a
cylindrical spike (spadix-like), with
carpellate flowers on the bottom, and staminate
flowers on the top - Inflorescence often
subtended by a linear bract - Flowers unisexual
(plants monoecious) - Tepals bract-like,
bristle-like, or scale-like Fruit- usually
an achene-like follicle
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Floral formula Staminate , T 1-? , A1-8,
G0 Carpellate , T3-?, A0, G1
Typha domingensis in flower
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Typha latifolia and Typha angustifolia (both
native to this area) Species to Review on
CD-ROM Typha domingensis Typha latifolia Typha
angustifolia
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Monocots Commelinoid Monocots Order Poales Family
Eriocaulaceae (pipewort family) Diagnostic
Characters Vegetative Habit perennial
herbs of shallow water, wet habitats Leaves
alternate, usually in basal rosettes,
grass-like Floral - Flowers in heads
subtended by an involucre of stiff
papery bracts plants often called Compositae
of the monocots. - Heads terminal, at the top
of a long scape - Flowers unisexual (plants
usually monoecious), inconspicuous Fruit- a
capsule
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Eriocaulon decangulare
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Species to Review on CD-ROM Eriocaulon
decangulare
Eriocaulon septangulare (native to this area)
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Monocots Commelinoid Monocots Order Poales Family
Xyridaceae Diagnostic Characters
Vegetative Habit perennial herb of wet
habitats Leaves alternate, usually 2-ranked,
flat to cylindrical Floral - Inflorescence
usually a conelike head or spike, with
spirally- arranged, imbricate, persistent
spikes - Inflorescence terminal, on a long
scape - Flowers bisexual, slightly zygomorphic,
differentiated into calyx and corolla
Fruit- usually a capsule
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Xyris caroliniana
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Floral formula X, K12, C 3 , A33, G 3
Species to Review on CD-ROM Xyris
caroliniana Xyris patylepis
Xyris patylepis
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Monocots Commelinoid Monocots Order Poales Family
Juncaceae (rush family) Diagnostic Characters
Vegetative Habit Herbs usually found in
damp habitats stems round and solid Leaves
alternate, 3-ranked, composed of a sheath and a
blade Blade is linear, flat or cylindrical
Floral - Flowers usually bisexual,
actinomorphic, inconspicuous, with 6 tepals -
Inflorescences terminal and highly branched or
head-like Fruit- a capsule Superficially
similar to grasses, but leaves are 3-ranked,
flowers have tepals, and fruits are
capsules.
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Juncus dichotomous, showing general habit
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Juncus effusus (native to this area) Floral
formula , T-6-, A(3-)6, G 3
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Juncus canadensis (native to this area)
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Species to Review on CD-ROM Juncus
dichotomous Juncus effusus
Juncus dichotomous, showing fruits
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Monocots Commelinoid Monocots Order Poales Family
Cyperaceae (sedge family) Diagnostic
Characters Vegetative Habit perennial
herbs, with solid stems usually triangular in
cross-section Leaves alternate, 3-ranked,
with a closed sheath Floral -
Inflorescence an arrangement of small spikes
(spikelets) - Flowers bisexual or unisexual
tepals lacking or reduced to scales, bristles or
hairs - Each flower subtended by one bract in
Carex carpellate flowers, a second bract forms a
sac (perigynium) enclosing the flower
Fruit- an achene, often with persistent perianth
bristles
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Cyperaceae characters
solid stem (culm), triangular cross-section
spikelets in inflorescence
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In this area, the genus Carex is the most diverse
in the family. Carex viridula (native to this
area)
Staminate and carpellate spikelets
Perigynium (left), and gynoecium (right,
inside perigynium)
habit
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Carex spikelet, showing peringia each flower is
subtended by one bract.
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Rhynchospora alba (native to this area)
Floral formula , T-0-6-, A1-3(-6), G 3
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Cyperus strigosus (native to this area)
inflorescence
spikelets
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Scirpus cyperinus (native to this area)
spikelets
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Species to Review on CD-ROM Carex
blanda Cyperus surianamensis Cyperus
strigosus Scirpus cyperinus Scirpus
tabernaemontani Rhynchospora corniculata
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Monocots Commelinoid Monocots Order Poales Family
Poaceae (grass family Graminae in some older
books) Diagnostic Characters
Vegetative Habit Herbs, or sometimes shrubs or
trees (bamboo). Stems are jointed and usually
round, and hollow in internodes, solid at
nodes. Leaves Leaves consist of sheath,
ligule, and blade. Floral - Basic unit of
inflorescence is a spikelet spikelets are
arranged in spikes, panicles, cymes or
racemes. - Each spikelet is subtended by two
bracts called glumes, and contains one or more
florets. Each floret consists of two bracts
(palea and lemma) subtending a flower. - Flowers
are small, bisexual or unisexual, usually
wind-pollinated. Fruit - usually a
caryopsis
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Vegetative Characters of Poaceae
closer view of ligule
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(No Transcript)
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Floral formula , T-2-, A(1-)3(-6), G 2-3
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Spikelets of wheat (Avena fatua)
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Corn, rice and wheat (each is a caryopsis)
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Zea mays staminate and carpellate inflorescences
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Young and mature ears
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Native Grass Species
Andropogon gerardii
Sorghastrum nutans
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Sporobolus heterolepis
Species to Review on CD-ROM No particular
species, but look at general images, and be able
to recognize members of this family.