The Monocots: Part 1
Overview, Basal, and “Petaloid” Groups
Spring 2014
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 tube member plastids with several
cuneate protein crystals
Lots of molecular support for monophyly
Monocot characters
Adventitious roots:
-derived from structures
other than another root
Monocot characters
• One cotyledon!
NONMONOCOT
MONOCOT
Monocot characters
Scattered vascular bundles in stem
– numerous; actually complex organization
– no vascular cambium (a few weird exceptions)
Monocot characters
Leaves:
– parallel venation in most monocots [may be
reversals with net-venation!]
– sheathing base
Trillium
Smilax
Monocot characters
• Pentacyclic, trimerous flowers with 2
perianth whorls and 2 whorls of stamens and
the gynoecium as 1 whorl
Monocot characters
Cuneate protein bodies in sieve cell plastids
– “wedge-shaped” inclusions
– function unknown
Additional features of monocots
• Leaves formed from the basal end of the
leaf primordium
• Usually with monosulcate pollen
• Lack glandular teeth on leaves
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 (11,000+ spp.)
Fig. 7.17 from Simpson
Phylogeny of Monocot Groups
Basal
“Petaloid”
Commelinid
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*
Amaryllidaceae
Iridaceae*
Orchidaceae*
*required families
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
Mainly terrestrial and some aquatic herbs, vines,
epiphytes, floating aquatics
Diversity: 3,300 species, 104 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 family
Araceae—Arisaema
Arisaema triphyllum
Jack-in-the-pulpit
Arisaema dracontium
green dragon
Arisaema
sikokianum
-Jack-in-the-pulpit is one of our common spring wildflowers
Araceae
Philodendron
Monstera
Amorphophallus (Corpse flower)
http://www.youtube.com/watch?v=FHaWu2rcP94
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”
Commelinid
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 family
Liliaceae - Lilium
Liliaceae
Erythronium
trout-lily
-native spring
wildflower of woodlands
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”
Commelinid
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 family
Alliaceae - Allium
Alliaceae
Economic plants and products:
•Allium species –
onions, leeks, garlic!
Ornamentals
“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 family
Perennating
structures
Equitant
leaves
Stamen position
opposite outer
tepals
Iridaceae characters
Iridaceae
diversity
Iris (Greek for rainbow)
-style branches broad, petaloid,
terminating in paired crests
-anthers appressed to style branches
Iris in wetland habitats
“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 family
Orchid growth habits
Epiphytic
Terrestrial
Orchid roots
velamen
Orchid
flower morphology
see Digital Flowers
pollinarium
Pollination
•function of column
& pollinia
Orchidaceae
http://www.youtube.com/watch?v=wmgKABRCZpo&feature=related
Richard Dawkins talking about orchid pollination
Comet Orchid
(Angraecum
sesquipedale)
http://www.youtube.com/watch?v=OMVN1EWxfAU
Morgan’s Sphinx Moth
Endemic to
Madagascar
Asparagales: Orchidaceae
Economic plants and products:
Vanilla flavoring extracted
from immature capsules
of Vanilla planifolia
Some other cool Asparagales
Agavaceae
Amaryllidaceae
Agavaceae – Agave and Yucca
Agave
Hosta
Yucca
Agave: bat pollinated
Yucca: moth pollinated
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
Amaryllidaceae
diversity
Amaryllidaceae
Corona sometimes present
Hymenocallis
spider-lily
Narcissus
daffodil, jonquil, narcissus