The Monocots: Part 1Overview, Basal, and “Petaloid” Groups

Spring 2010

Figure 9.1 from the textFigure 9.1 from the text

Synapomorphies of Monocots

• Root system adventitious

• One cotyledon

• Stems with scattered vascular bundles (no 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!

MONOCOTMONOCOTNON-NON-MONOCOTMONOCOT

Monocot charactersLeaves:

– 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 charactersScattered vascular bundles in stem

– numerous; actually complex organization– no vascular cambium (a few weird exceptions)

Monocot characters

• Pentacyclic, trimerous flowers with 2 perianth whorls

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.)

Phylogeny of Monocot Groups

AcoralesAlismatalesAsparagalesLilialesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinoid

Basal and “Petaloid” Monocot Groups

Order AcoralesAcoraceae

Order AlismatalesAraceae

Alismataceae

Order LilialesLiliaceae

Order AsparagalesAgavaceae AlliaceaeAmaryllidacaeeIridaceaeOrchidaceae

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)• Required taxa: (none, but Acorus

evolutionarily important)

Acorus (sweet flag)– The most basal monocot! Aquatic.

“Petaloid” Monocots—Alismatales:

Araceae(The Arum Family)

• Cosmopolitan; greatest diversity in tropical regions

• Terrestrial and aquatic herbs, vines, epiphytes, floating aquatics

• Diversity: 2,830 species, 109 genera

• Flowers: many, small; lacking extensive perianth, carpels 2-3; spatially separated in inflorescence or sometimes plants dioecious

• Significant features: inflorescence – spadix subtended by a spathe

• Special uses: many ornamentals; Colocasia as food

• Required taxa: *Arisaema, Lemna

* Change from lab manual!

Araceae—Arisaema

Arisaema triphyllumArisaema triphyllumJack-in-the-pulpitJack-in-the-pulpit

Arisaema dracontiumArisaema dracontiumgreen dragongreen dragon

-spathe overlapping below, mostly arched above,striped or marked-spadix usually slender and elongate-flowers unisexual and only at the base of the spadix

Arisaemasikokianum

Araceae

Monstera

Philodendron

Amorphophallus

Araceae: Lemna and friends

Lemna ~ duckweed

•Reduced plant body: no stem or leaves; sometimes no roots•Rarely flower

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: 80 species, 11 genera

• Flowers: sepals & petals distinct, many apocarpous carpels

• Significant features: rhizomatous

• Special uses: ornamental aquatics

• Required taxa: Sagittaria

Liliales: Liliaceae in the broad sense

…are a garbage can taxon.

Plus many membersof Asparagales…

Figure 9.14 from the text

“Petaloid” Monocots—Liliales:

Liliaceae(The Lily Family)

• Widely distributed in temperate regions of the Northern Hemisphere

• Herbs, usually with bulbs or contractile roots

• Number of species: ca. 600 species, in 16 genera

• Flowers: tepals 6, distinct, carpels 3, stamens 6

• Significant features: Fruit a loculicidal capsule, sometimes a berry

• Special uses: many ornamentals• Required taxa: Erythronium, Tulipa

Liliaceae - Lilium

Liliaceae

Erythroniumtrout-lily

LiliaceaeEconomic plants and products (horticultural):

LiliumEaster lily

Tulipatulip

Asparagales vs. Liliales

• Herbs; not succulent•Tepals often spotted•Nectaries at base of tepals/filaments•Styles 1 (trifid) or 3•Seed coat present•No phytomelan crust (seeds not black)

• Herbs to woody; sometimes succulent•Tepals not spotted•Nectaries septal•Styles usually 1, simple•Seed coat collapsed to + present•Phytomelan crust (seeds black) from dry fruits; not in fleshy fruit

Figure 9.18 from the text

“Petaloid” Monocots—Asparagales:

Agavaceae(The Agave Family)

• Warm temperate to tropical regions of the New World; maximum diversity in Mexico

• Rosette herbs, 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• Special uses: fiber, tequila, ornamentals.• Required taxa: Agave, Yucca, Hosta

Agavaceae – Agave and Yucca

Agave

Yucca

Agave: bat pollinated Yucca: moth pollinated

Agavaceae: Hosta

Asparagales: Agavaceae

Economic plants and products:

Agave tequila

Asparagales: Agavaceae

Economic plants and products:

•Fiber for rope from species of Yucca and Agavee.g., sisal hemp

“Petaloid” Monocots—Asparagales:

Alliaceae(Onion Family)

• Widely distributed in temperate and tropical regions; also semiarid.

• Bulb-forming herbs

• Number of species: ca. 645 species, in 13 genera

• Flowers: Often showy, tepals 6, stamens 6, 3 connate carpels, ovary superior; fruit a loculicidal capsule.

• Significant features: sulfur-containing compounds

• 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:

Amaryllidaceae(Amaryllis or Daffodil Family)

• 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: 870 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)

• Required taxa: Narcissus, Hippeastrum

Amaryllidaceae

Amaryllidaceae

Hymenocallisspider-lily

Narcissusdaffodil, jonquil, narcissus

Corona sometimes present

Amaryllidaceae: Hippeastrum

“Petaloid” Monocots—Asparagales:

Iridaceae(The Iris Family)

• Widespread in tropical and subtropical regions; absent in Australia.

• 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; carpels 3, fused into an inferior ovary; fruit a loculicidal capsule

• Significant features: leaves equitant

• Special uses: many ornamentals; saffron (Crocus sativus)

• Required taxa: Iris

Iridaceae

“Petaloid” Monocots—Asparagales:

Orchidaceae(The Orchid Family)

• Widespread throughout the world; maximal diversity in tropical regions

• Primarily epiphytes; some terrestrial herbs, occasionally vines• Diversity: ca. 19,500 species in 775-800 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); 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

*change from lab manual

Orchid flower morphology

Orchidaceae

Pollination•function of column & pollinia

Asparagales: Orchidaceae

Economic plants and products:

Vanilla flavoring extracted from immature capsules

of Vanilla planifolia