The Monocots: Part 1
Overview, Basal, and “Petaloid” Groups
Spring 2012
Figure 7.1 from the text
Synapomorphies of Monocots
• Root system adventitious
• One cotyledon
• Stems with scattered vascular bundles (no
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secondary growth); herbaceous
Leaves parallel-veined with a sheathing
base
Flowers pentacyclic (5 whorls), trimerous
Sieve cell plastids with several cuneate
protein crystals
Lots of molecular support for monophyly
Additional features of monocots
• Leaves formed from the basal end of the
leaf primordium
• Usually with monosulcate pollen
• Lack glandular teeth on leaves
Monocot characters
• One cotyledon!
NONMONOCOT
MONOCOT
Monocot characters
Leaves:
– parallel venation in most monocots [may be
reversals with net-venation!]
– sheathing base
Trillium
Smilax
Monocot characters
Cuneate protein bodies in sieve cell plastids
– “wedge-shaped” inclusions
– function unknown
Monocot characters
Adventitious roots:
-derived from structures
other than another root
Monocot characters
Scattered vascular bundles in stem
– numerous; actually complex organization
– no vascular cambium (a few weird exceptions)
Monocot characters
• Pentacyclic, trimerous flowers with 2
perianth whorls and two whorls of stamens
How many monocots?
•ca. 3,000 genera
•ca. 65,000 species
•22-25% of angiosperms
•Include:
-aroids
-bananas
-lilies
-gingers
-orchids (20,000+ spp.)
-irises
-palms
-grasses (10,000 spp.)
Fig. 7.17 from Simpson
Phylogeny of Monocot Groups
Basal
“Petaloid”
Commelinoid
Acorales
Alismatales
Liliales
Asparagales
Dioscoreales
Pandanales
Arecales
Poales
Commelinales
Zingiberales
Basal and “Petaloid” Monocot Groups
Order Acorales
Acoraceae
Order Alismatales
Araceae
Alismataceae
Order Liliales
Liliaceae
Order Asparagales
Agavaceae
Alliaceae
Amaryllidacaee
Iridaceae
Orchidaceae
Basal Monocots:
Acorales: Acoraceae
• Widespread, temperate throughout tropical
regions
• Aquatic herb
• Diversity: 1-3 spp. in 1 genus (Acorus)
• Flowers: typical of Araceae, coalesced into
a spike-like spadix
• Significant features: Sister to the rest of the
monocots; contain ethereal oils.
• Special uses: none
• Family not required, but Acorus
evolutionarily important
Acorus (sweet flag)–
The most basal monocot! Aquatic.
“Petaloid” Monocots—Alismatales:
Araceae
(The Arum Family)
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Cosmopolitan; greatest diversity in tropical regions
Terrestrial and aquatic herbs, vines, epiphytes,
floating aquatics
Diversity: 3,300 species, 109 genera
Flowers: many, small; lacking extensive perianth,
carpels 2-3; if unisexual then spatially separated in
inflorescence or sometimes plants dioecious
Significant features: inflorescence – spadix subtended
by a spathe (specialized leaf)
Special uses: many ornamentals; Colocasia as food
Required taxa: Arisaema, Lemna
Araceae—Arisaema
Arisaema triphyllum
Jack-in-the-pulpit
Arisaema dracontium
green dragon
Arisaema
sikokianum
-spathe margins overlapping below, spathe mostly arched above,
striped or marked
-spadix usually slender and elongate
-flowers unisexual and only at the base of the spadix
Araceae
Philodendron
Monstera
Amorphophallus
Araceae: Lemna and friends
•Reduced plant body: no stem or leaves;
sometimes no roots
•Rarely flower
Lemna ~ duckweed
Alismatales: Araceae
Economic plants and products:
Colocasia esculenta
•Taro “root” or dasheen
“poi”
•10% of the world uses as
staple (starch) in diet
“Petaloid” Monocots—Alismatales:
Alismataceae
(The Water Plantain Family)
• Widely distributed
• Aquatic & wetland rhizomatous herbs
• Number of species: 88 species, 15 genera
• Flowers: sepals & petals distinct, many
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apocarpous carpels; flowers or floral axes
often whorled
Significant features: rhizomatous
Special uses: ornamental aquatics
Family not required
Phylogeny of Monocot Groups
Basal
“Petaloid”
Commelinoid
Acorales
Alismatales
Liliales
Asparagales
Dioscoreales
Pandanales
Arecales
Poales
Commelinales
Zingiberales
Liliales
• Nectaries at base of tepals
• Spots on tepals
• Extrorse anthers
“Petaloid” Monocots—Liliales:
Liliaceae
(The Lily Family)
• Widely distributed in temperate regions of
the Northern Hemisphere
• Perennial herbs, usually with bulbs and
contractile roots
• Number of species: ca. 600 species, in 16
genera
• Flowers: tepals 6, distinct, carpels 3,
stamens 6
• Significant features: Fruit a loculicidal
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capsule, sometimes a berry; no onion-like
odor
Special uses: many ornamentals
Required taxa: Erythronium, Tulipa
Liliaceae - Lilium
Liliaceae
Erythronium
trout-lily
-bulbs ovate to elongate
-scapose herbs with
2 leaves
(1 if non-flowering)
-tepals 6, spreading to
reflexed
-native wildflowers
Tulipa
-scapose herbs from tunicate bulbs
-leaves 2-several on a stem
-perianth campanulate to cuplike
-tepals 6, erect
-stigma prominently 3-lobed
Liliaceae
Economic plants and products (horticultural):
Lilium
Easter lily
Tulipa
tulip
Phylogeny of Monocot Groups
Basal
“Petaloid”
Commelinoid
Acorales
Alismatales
Liliales
Asparagales
Dioscoreales
Pandanales
Arecales
Poales
Commelinales
Zingiberales
Asparagales
vs.
Liliales
• Herbs to woody;
• Herbs; not succulent
sometimes succulent
•Tepals not spotted
•Nectaries septal
•Style usually 1, simple
•Seed coat collapsed
to + present
•Phytomelan crust
(seeds black) from dry
fruits; not in fleshy fruit
•Tepals often spotted
•Nectaries at base
of tepals/filaments
•Styles 1 (trifid) or 3
•Seed coat present
•No phytomelan crust
(seeds not black)
Figure 7.32 from the text
“Petaloid” Monocots—Asparagales:
Alliaceae
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(Onion Family)
Widely distributed in temperate and tropical
regions; also semiarid.
Bulb-forming herbs with basal, usually narrow
leaves
Number of species: ca. 600 species, in 13 genera
Flowers: Often showy, tepals 6, stamens 6, 3
connate carpels, ovary superior; inflorescence
umbellate; fruit a loculicidal capsule.
Significant features: sulfur-containing compounds
(onion odor)
Special uses: onion, garlic, leek, shallots, chives,
used as food & seasonings; ornamentals
Required taxa: Allium
Alliaceae - Allium
-scapose herbs with bulbs +
contractile roots
-basally clustered leaves
-umbellate inflorescence with
bracts
-6 petaloid tepals + 6 stamens
-loculicidal capsule + black seeds
Alliaceae
Economic plants and products:
•Allium species –
onions, leeks, garlic!
Ornamentals
“Petaloid” Monocots—Asparagales:
Agavaceae
(The Agave Family)
• Warm temperate to tropical regions of the
New World; maximum diversity in Mexico
• Rosette herbs to small trees, often with
succulent leaves
• Number of species: ca. 300 species in 8-13
genera
• Flowers: tepals 6, stamens 6, carpels 3, fruits
a loculicidal capsule
• Significant features: large, paniculate
inflorescence; dimorphic chromosomes
• Special uses: fiber, tequila, ornamentals.
• Family not required
Agavaceae – Agave and Yucca
Agave
Yucca
Agave: bat pollinated Yucca: moth pollinated
Agave (L) vs. Yucca (R)
• Perianth tubularfunnelform, 6-parted
• Stamens exserted
beyond the perianth,
anthers versatile
• Ovary inferior
• Capsule loculicidal
• Bat-pollinated
• Perianth of 6 flat, free
tepals
• Stamens shorter than
the tepals, anthers
basifixed
• Ovary superior
• Fruit indehiscent
(berry-like) or
septicidal capsule
• Moth-pollinated
Agavaceae: Hosta
-rhizomatous, scapose perennials
-leaves with a distinct petiole
-perianth tubular-funnelform,
white, bluish or lavender
-stamens 6, epipetalous or hypogynous
-fruit a loculicidal
capsule
Asparagales: Agavaceae
Economic plants and products:
Agave tequila
Asparagales: Agavaceae
Economic plants and products:
•Fiber for rope from species of Yucca and Agave
e.g., sisal hemp
“Petaloid” Monocots—Asparagales:
Amaryllidaceae
(Amaryllis or Daffodil Family)
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Widely distributed in temperate to tropical regions;
maximal diversity in South Africa, Andean South
America, and the Mediterranean
Bulb-forming herbs with contractile roots
Number of species: 850 species in 59 genera
Flowers: often showy; tepals 6; stamens 6,
sometimes adnate to perianth; carpels 3, inferior
ovary; fruit usually a loculicidal capsule
Significant features: special alkaloid compounds
present
Special uses: many ornamentals (Narcissus,
Hippeastrum)
Family not required
Amaryllidaceae
diversity
Amaryllidaceae
Corona sometimes present
Hymenocallis
spider-lily
Narcissus
daffodil, jonquil, narcissus
Narcissus
-scapose, perennial herbs from bulbs
-perianth of 6 basally connate tepals,
yellow and/or white
-cuplike to trumpetlike corona present
-stamens 6, epipetalous
Amaryllidaceae: Hippeastrum
-perennial, scapose herbs from large bulbs
-perianth of 6 basally connate tepals, white
to pink to salmon or red
-corona minute
-stamens 6, epipetalous
“Petaloid” Monocots—Asparagales:
Iridaceae
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(The Iris Family)
Widespread in tropical and subtropical regions;
absent in Australia.
Perennial herbs forming rhizomes, corms, or bulbs
Number of species: ca. 1,750 species, 67 genera
Flowers: radial or bilateral, showy; tepals 6, outer
tepals often differentiated from inner; stamens (2) 3,
opposite outer tepals; carpels 3, fused into an
inferior ovary; fruit a loculicidal capsule
Significant features: leaves unifacial or terete,
equitant
Special uses: many ornamentals; saffron (Crocus
sativus)
Required taxa: Iris
Iridaceae
diversity
Iris
-rhizomatous herbs
-leaves equitant, in a fan
-spathes 2
-style branches broad, petaloid,
terminating in paired crests
anthers appressed to style branches
“Petaloid” Monocots—Asparagales:
Orchidaceae
(The Orchid Family)
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Widespread throughout the world; maximal diversity in
tropical regions
Primarily epiphytes; some terrestrial herbs, occasionally vines
Diversity: ca. 20,000 species in 700-800 genera
Flowers: showy, usually resupinate, bilateral, the median inner
tepal differentiated into a labellum (lip); highly modified
androecial and gynoecial parts, fused into a column; pollen
grouped into soft or hard masses (pollinia) united by a stalk
into a pollinarium; ovary inferior; placentation parietal; fruit a
capsule dehiscing with (1-)3 or 6 slits; seeds tiny, dust-like
Significant features: among the most specialized of all
angiosperm flowers
Special uses: many ornamentals; Vanilla
Required taxa: family only
Orchid
flower morphology
pollinarium
Pollination
•function of column
& pollinia
Orchidaceae
http://www.youtube.com/watch?v=wmgKABRCZpo&feature=related
Richard Dawkins talking about orchid pollination
Morgan’s Sphinx Moth
Endemic to
Madagascar
Comet Orchid
(Angraecum
sesquipedale)
Asparagales: Orchidaceae
Economic plants and products:
Vanilla flavoring extracted
from immature capsules
of Vanilla planifolia