The Monocots: Part 2Commelinid Monocots

Spring 2014

Phylogeny of Monocot Groups

AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

Fig. 7.17

Commelinid 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

Fig. 7.45

Commelinid Monocot Groups

Order Arecales – PalmsArecaceae (Palmae)

Order Commelinales – Spiderworts, bloodworts, pickerel weeds

Order Zingiberales – Ginger, banana, and allies

Order Poales – Bromeliads, Cat-tails, Rushes, Sedges, and GrassesTyphaceae*Juncaceae* Cyperaceae*Poaceae (Gramineae)*

*required families

Commelinoid Monocots:

Arecales: Arecaeae (Palmae)• Widespread throughout tropical and warm

temperate regions• “Trees” or “shrubs”, typically unbranched• Diversity: ca. 2,000 species in 190 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

• Family not required

Arecaceae – Cocos nucifera

ArecaceaeEconomic plants and products:

Cocos nuciferaCoconut, oil

ArecaceaeEconomic plants and products:

Phoenix dactyliferaDates

Phylogeny of Monocot Groups

AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

Commelinid Monocots: Zingiberales

• 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 penni-parallel 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, mainly tropical• Not required

Fig. 7.55

Zingiberalesdiversity

Fig. 7.56

Phylogeny of Monocot Groups

AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

Characters of Poales• Silica bodies (in silica cells) in the

epidermis• Styles strongly branched• Loss of raphide (needle-like) crystals in

most• Much molecular support for monophyly• Wind pollination has evolved several

times independently within the order• Ecologically extremely important

Fig. 7.63

Commelinoid Monocots—Poales:

Typhaceae(The Cattail Family)

• Widely distributed, especially in Northern Hemisphere

• Emergent aquatic rhizomatous herbs• Diversity: 8-13 species in 1 genus• Flowers: small, unisexual; separated

spatially on dense, compact spicate inflorescences; placentation apical

• Significant features: rhizomatous; long slender leaves; characteristic inflorescence

• Special uses: ornamental aquatics• Required taxa: Typha

Sparganium

This genus is placed inits own family, theSparganiaceae, in yourtext, but it is closelyrelated to Typhaceae andis included in Typhaceaein many treatments.

Typha

Commelinid Monocots—Poales:

Juncaceae(The Rush Family)

• Worldwide, mostly temperate regions; wet or damp habitats

• Rhizomatous herbs, stems round and solid• Diversity: 350 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

Distichia

Juncaceae: Juncus

-important in manywetland habitats

Commelinid Monocots—Poales:

Cyperaceae(The Sedge Family)

• Worldwide, usually in damp or semi-aquatic sites• Rhizomatous herbs, stems usually triangular in

cross section and solid• Diversity: 5,000 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

Cyperaceae versus Juncaceae:Field Character

“Sedges have edges…

…and rushes roll.”

Fig. 7.65

Fig. 7.66D

Cyperaceae

Sedge spikelet

flower + subtending bract = floret

Flowers:• Arranged in spikelets• Reduced• Wind-pollinated • Subtended by one bract• Reduced/absent perianth

flower

From Zomlefer 1994

Cyperaceae

Cyperus

Eleocharis Rhynchospora(note bristle perianth)

Fruit type is the achene: very important inthe taxonomy of the family.

Cyperaceae

http://waynesword.palomar.edu/termfl3.htm

Cyperaceae: Carex

-presence of the perigynium (a sac-likebract surrounding the female flower) in addition to the subtending bract-leaves usually with a ligule-ecologically important, especially in wetlands

Cyperaceae: Carex

Commelinid Monocots—Poales:

Poaceae (Gramineae)(The Grass Family)

• Cosmopolitan• Primarily herbs, often rhizomatous; “trees” in most

bamboos; stems are called culms, hollow or solid• Diversity: >11,000 species in ca. 650 genera• Flowers: small petals 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 family

Ecologicalimportance

Economicimportance Zea mays

Oryza sativaTriticum aestivum

weeds

sugar cane

bamboo

Poaceae: vegetative structure

ligule

Poaceae: spikelet and flower structure

flower

Images fromGrasses of Iowa(mostly)

• 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.

Anatomy of the

Caryopsis (Grain)

Poaceae: caryopsis (grain)

Setariafoxtail

Zea mayscorn or maize

Origin of grassesca. 70-80 myain southern-hemisphereforests

early grasses

Panicgrasses*(Panicoideae)

Rices(Ehrhartoideae)

Bluegrasses(Pooideae)

Bamboos(Bambusoideae)

Puelioideae

PharoideaeAnomochlooideae

Needlegrasses*(Aristidoideae)

Lovegrasses*(Chloridoideae)

Micrairoideae*

Reeds(Arundinoideae)

Oatgrasses(Danthonioideae)

Major radiationin Oligocene-Miocene epochsinto open habitats

Origin of grassesca. 70-80 myain forests

+

Stamensreduced to 3

C4 photosynthetic pathway(in warm season grasses)is advantageous under higher temperatures, higherlight, and less water when atmospheric CO2 is < 500 ppm

Dispersal!

Poaceae: Bamboos

Oryza (rice)

Triticum (wheat)

Zea (maize or corn)

For more informationand images:

http://www.eeob.iastate.edu/research/iowagrasses/

The Grasses of Iowa

Grasses, Sedge, Rushes!• Stem terete, hollow, or solid, jointed

• Leaf ranks 2

• Leaf sheath Open, ligule

• Inflor: Spikelets

• Perianth: Lodicules

• Fruit: Caryopsis

• Triangular, solid, not obviously jointed

• 3

• Closed

• Spikelets

• None or bristles/scales

Achene

• Terete, solid, not obviouslyjointed

• 3

• Open

• Cymose

• 6 chaffy tepals

• Capsule

“Graminoids” - Comparison

Next time: The “Basal” Eudicots…