This document provides information about the monocotyledonous flowering plants, or monocots. It discusses their defining characteristics and classification. Specifically, it describes the monocot orders Alismatales, Arecales, Zingiberales, and Poales. For each order, it lists the included families and provides details about their morphological features and economically important species. Images are included to illustrate various monocot structures and taxa. The document is an informative overview of monocot diversity and systematics.

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Diversity And Classification of
Flowering Plants:
Monocots
Michael G. Simpson
Monocotyledons
(Monocotyledonae, Monocots,
Liliidae)
• Monophyletic group
• Comprise 22% of all angiosperms
• Relationships to other “basal” angiosperms
unclear at present
• aroids, lilies, gingers, orchids, irises, palms,
grasses
Apomorphies of the Monocots
• sieve tube plastids with cuneate (wedgeshaped) proteinaceous inclusions
• atactostele stem vasculature
• parallel leaf venation
• single cotyledon
• NOTE: a trimerous flower merosity is not a
Monocot apomorphy
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Apomorphies of the Monocots
• sieve tube plastids with cuneate (wedge-shaped)
proteinaceous inclusions
• No monocot has true vascular cambium that
produces wood
Apomorphies of the Monocots
• atactostele stem vasculature
Apomorphies of the Monocots
• parallel leaf venation (penni-parallel in some)
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Apomorphies of the Monocots
• single cotyledon
ALISMATALES
Alismataceae
Aponogetonaceae
Araceae (including Lemnaceae)
Butomaceae
Cymodoceaceae
Hydrocharitaceae
Juncaginaceae
Limnocharitaceae
Posidoniaceae
Potamogetonaceae
Ruppiaceae
Scheuchzeriaceae
Tofieldiaceae
Zosteraceae
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ALISMATALES
Araceae - Arum family
(Arum, a name used by Theophrastus).
111 genera / 2980 species
The Araceae are distinguished from related
families in having bifacial leaves, a spadix of
numerous, small flowers with a subtending spathe,
endospermous seeds, and raphide crystals.
P 2+2,3+3,(2+2),(3+3) or 0 [4+4,(4+4)] A 4,6,8 or
(4,6,8) [1-12] G (3) [1-(∞)] superior, hypanthium
absent.
Araceae - Arum family
• Members of the family have distributions in
tropical and subtropical regions.
• Economic importance includes many taxa
important food sources (rootstocks, leaves, or
fruits) in the tropics, e.g., Alocasia, Colocasia
esculenta (taro), Monstera; some species are
cultivated ornamentals, e.g., Anthurium, Caladium
(elephant's ear), Dieffenbachia (dumb cane),
Monstera, Philodendron, Zantedeschia (calla-lily).
• Amorphophallus titanum is unique in having the
largest inflorescences of any flowering plant.
ARACEAE
•
•
•
•
•
Colocasia “gabi” or “taro”
Alocasia
Caladium “Corazon de Maria”
Dieffenbachia “dumb cane”
Anthurium
Aglaonema commutatum
A. modestum
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Amorphophallus titanum
Largest inflorescence in world
Arisaema triphyllum Jack-in-the-pulpit
Wolffia sp. Watermeal
Smallest flower in world
Lemna minuscula
Duckweed
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Pistia stratiotes Water-lettuce
Monstera deliciosa
Monstera deliciosa
Monstera deliciosa
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Pothos sp.
Xanthosoma sagittifolium
Xanthosoma sagittifolium
Zantedeschia aethiopica Calla-lily
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Zantedeschia aethiopica Calla-lily
ASPARAGALES
• Very large order!
• Apomorphy: phytomelan in seed coat
(lost in some taxa)
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ASPARAGALES
Agapanthaceae* [Alliaceae]
Hyacinthaceae* [Asparagaceae]
Agavaceae* [Asparagaceae]
Hypoxidaceae
Alliaceae*
Iridaceae
Amaryllidaceae [Alliaceae]
Ixioliriaceae
Aphyllanthaceae* [Asparagaceae]
Lanariaceae
Asparagaceae
Laxmanniaceae* [Asparagaceae]
Asphodelaceae* [Xanthorrhoeaceae]
Orchidaceae
Asteliaceae
Ruscaceae* [Asparagaceae]
Blandfordiaceae
(incl. Convallariaceae)
Boryaceae
Tecophilaeaceae
Doryanthaceae
Themidaceae* [Asparagaceae]
Hemerocallidaceae* [Xanthorrhoeaceae]
Xanthorrhoeaceae*
Xeronemataceae
Orchidaceae - Orchid family
(orchis, testicle, from the shape of the root tubers). 700-800
genera / ca. 20,000 species
• mycorrhizal, mostly perrennial, terrestrial or epiphytic
herbs having trimerous,
• often resupinate flowers with a showy labellum
• androecium and gynoecium adnate (termed a column,
gynostegium, or gynostemium)
• the pollen grains often fused into a 1-several masses
(pollinia), bearing a sticky-tipped stalk, pollinia and
stalk termed a pollinarium, which is the unit of pollen
dispersal during pollination.
P (3+3) A 1-3, when 1 a pollinarium G (3), inferior, with
gynostemium
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labellum
column
Caladenia longiclavata Australia
Calopogon - a non-resupinate orchid
Cattleya sp.
Cymbidium sp.
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Dendrobium
phalaenopsis
Cypripedium sp. Lady’s Slipper
Dracula chimaera
Dracula vampira
Encyclia sp. Cockleshell Orchid
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Epidendrum sp.
Ludisia sp.
Orchis spectabilis
Oncidium lanceanum
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Paphiopedilum sp.
Pseudobulb
Stanhopea trigrinum
Thelymitra antennifera Australia
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Vanilla planifolia- fermented capsules
Vanilla Orchid
Commelinid Monocots
Apomorphy:
UV-fluorescent
organic acids
(including
coumaric, diferulic,
and ferulic acid)
that impregnate the
cell walls.
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ARECALES
Arecaceae (Palmae) - Palm family
(from areca, Portuguese for the betel palm). ca. 190 genera / ca. 2,000 species.
The Arecaceae are distinctive in having a rhizomatous, lianous, or
usually arborescent stem, with large, sheathing, plicate leaves, a
fleshy, usually drupaceous fruit, and seeds lacking starch. The
plicate leaves is an apomorphy for the family.
P 3+3 [0,2+2,∞] A 3+3 or (3+3) [3,∞; 0 in female fls.] G 3 or (3)
[1,2,4-10; 0 in male fls.], superior.
Arecaceae
• Leaves- acrocaulis; simple, pinnate,
bipinnate, costapalmate, palmate
• Pseudopetiole
• Crownshaft
• Rhizomatous, lianous, herbs, trees
Fruit a drupe
reduplicate vs. induplicate
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•
•
•
•
•
•
Cocos nucifera- coconut
Phoenix dactylifera- date palm
Elaeis oleifera- oil palm
Metryoxylon- sago palms
Copernicia cerifera- wax palm
Areca catechu- as a stimulant
Archontophoenix cunnighamiana King Palm
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Syagrus romanzoffianum Queen Palm
Chamaerops humilis Mediterranean Palm
Calamus Rattan Palm
Jubea chilensis
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Nypa fruticans - a rhizomatous palm
Licuala peltata
Phoenix canariensis
Canary I. Palm
Phoenix dactylifera
Date Palm
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Rhopalostylis sapida
ZINGIBERALES - Ginger Group
Apomorphies:
Penni-parallel venation
Supervolute leaf “ptyxis”
(1/2 of leaf rolled within the other)
Diaphraghmed air chambers
Silica cells
Inferior ovary
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midrib
Zingiberaceae - Ginger family
(from a pre-Gr. name, possibly from India). 50 genera / 1,200 species
The Zingiberaceae are distinguished from related families
of the Zingiberales in having distichous, usually ligulate
leaves with a single, dithecal stamen and a petaloid
labellum derived from two staminodes.
P (3+3) A 1 fertile + 2 + (2) petaloid staminodes G (3), inferior.
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Zingiberaceae - Ginger family
(from a pre-Gr. name, possibly from India). 50 genera / 1,200 species
Economic importance includes the source of important spice plants,
e.g., Curcuma spp., including C. domestica (turmeric), Elettaria
Musaceae
Strelitziaceae
cardamomum (cardamom), and Zingiber spp., including Z. officinale
(ginger); some species are grown as cultivated ornamentals, e.g.,
Alpinia and Hedychium.
Zingiberaceae
ZINGIBERACEAE
• 1 style, clasped
by anther (like
Schistosoma)
• Fruit capsule
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inner tepal
Outer tepal
Connate staminodes
Alpinia Shell Ginger
Hedychium
Hedychium
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filament
staminodes
Inner tepals
Ovary
Outer tepals
Hedychium
Nicolaia elatior
Cannaceae - Canna-Lily family
(Gr. canna, a reed). 1 genus (Canna) / 25 species
The Cannaceae are distinguished from related
families of the Zingiberales in having usually
distichous leaves and flowers with one petaloid,
monothecal stamen associated with 1-4[5]
petaloid staminodes.
P 3+3 A 1, petaloid monothecal + 1-4 petaloid
staminodes G (3), inferior.
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Musaceae
Cannaceae
Canna sp. Cannaceae
staminodes
Inner tepal
Outer tepal
Canna sp. Cannaceae
Canna sp. Cannaceae
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Canna sp. Cannaceae
staminode
half staminode
style/stigma
• Fruit capsule
• Canna sp.
half anther
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Cyperaceae - Sedge family
Cyperaceae - Sedge family
(Gr. for several species of Cyperus). 98 genera / 4,350 species
(Gr. for several species of Cyperus). 98 genera / 4,350 species
The Cyperaceae are distinctive in being herbs with usually
3-sided, solid-pithed stems, closed-sheathed, often tristichous
leaves, the inflorescence a “sedge spikelet,” consisting of a
central axis bearing many sessile, distichous or spiral bracts,
each subtending a single, reduced unisexual or bisexual
flower, with perianth absent or reduced to bristles or scales,
usually 3 stamens, and a 2–3-carpellate ovary, the fruit a 2- or
3-sided achene.
Economic importance is limited, with some
species used as mats, thatch, weaving material, or writing
material (Cyperus papyrus, papyrus, the culm pith of which
was historically used to make paperlike scrolls), a few used
as ornamental cultivars (e.g., Cyperus involucratus, umbrella
plant), and some species, such as the nutsedges, being
noxious weeds.
P 6 or 0 [1-∞] A 3 [1-6+] G (2-3)[(4)], superior.
Glomerule
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involucral
bracts
spikelet
perigynia
enclosing
ovaries
female
spikelet
Carex praegracilis
Cyperus involucratus Umbrella Sedge
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spikelet:
bracts
distichous
Cyperus sp.
Cyperus involucratus
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Poaceae/ Graminae - Grass family
(after Poa, Gr. name for a grass). 668 genera / 9,500 species
STEMS: hollow-pithed
LEAVES: open-sheathed, distichous, with a ligule at inner
junction with blade
INFLORESCENCE: grass spikelet
= axis + two basal glumes + 1-∞ florets
Floret = short lateral axis + lemma + palea + flower
FLOWER: P 2-3 lodicules A 2-3 (pendulous) G (2-3)
FRUIT: caryopsis (grain).
POACEAE
• Spikelet – basic inflorescence, made up of
florets, subtended by 2 bracts called glumes
• Floret – flower, each subtended by even
more glumes called lemma and palea, unior bisexual
• Rachilla – axis of spikelet
POACEAE
• Lemma – outer, flowering glume
• Palea – inner bract, between flower and
rachilla
• Lodicules – modified perianth
• Stamens in 3 whorls
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DISTRIBUTION: worldwide.
ECONOMIC IMPORTANCE:
1) agricultural grains (most important food in world):
barley (Hordeum)
corn (Zea)
oats (Avena)
rice (Oryza)
rye (Secale)
wheat (Triticum);
2) alcoholic beverages: beer, whiskey, gin
3) forage and grazing plants;
4) important components of many ecosystems, such as
grasslands and savannahs.
POACEAE
•
•
•
•
•
•
•
•
•
•
•
Oryza sativa “rice”
Zea mays “corn”
Triticum “wheat”
Avena “oats”
Hordeum “barley”
Saccharum “sugar cane”
Panicum
Axonopus
Eleusine
Digitaria
Paspalum
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distichous
leaf
arrangement
open sheath
ligule
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Bamboos
Fruit: Grain
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Cynodon dactylon
Bermuda Grass
Pennisetum setaceum
Melinis repens
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