The Monocots: Part 1Overview, 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

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 charactersAdventitious roots:

-derived from structures other than another root

Monocot characters• One cotyledon!

MONOCOTNON-MONOCOT

Monocot charactersScattered vascular bundles in stem

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

Monocot charactersLeaves:

– 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 charactersCuneate 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 GroupsAcoralesAlismatalesLilialesAsparagalesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

Basal and “Petaloid” Monocot GroupsOrder Acorales

Acoraceae

Order AlismatalesAraceae*

Alismataceae

Order LilialesLiliaceae*

Order AsparagalesAgavaceae Alliaceae*AmaryllidaceaeIridaceae*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)

• 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 triphyllumJack-in-the-pulpit

Arisaema dracontiumgreen dragon

-Jack-in-the-pulpit is one of our common spring wildflowers

Arisaemasikokianum

Araceae

Monstera

Philodendron

Amorphophallus (Corpse flower)

http://www.youtube.com/watch?v=FHaWu2rcP94

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: 88 species, 15 genera• Flowers: sepals & petals distinct, many

apocarpous carpels; flowers or floral axes often whorled

• Significant features: rhizomatous• Special uses: ornamental aquatics• Family not required

Phylogeny of Monocot GroupsAcoralesAlismatalesLilialesAsparagalesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

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

capsule, sometimes a berry; no onion-like odor

• Special uses: many ornamentals• Required family

Liliaceae - Lilium

Liliaceae

Erythroniumtrout-lily

-native springwildflower 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

LiliaceaeEconomic plants and products (horticultural):

LiliumEaster lily

Tulipatulip

Phylogeny of Monocot GroupsAcoralesAlismatalesLilialesAsparagalesDioscorealesPandanalesArecalesPoalesCommelinalesZingiberales

Basal“Petaloid”Commelinid

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• Style usually 1, simple• Seed coat collapsed to + present• Phytomelan crust (seeds black) from dry fruits; not in fleshy fruit

Figure 7.32 from the text

“Petaloid” Monocots—Asparagales: Alliaceae(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

AlliaceaeEconomic plants and products:

• Allium species – onions, leeks, garlic!

Ornamentals

“Petaloid” Monocots—Asparagales: Iridaceae(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

Stamen positionopposite outertepals

Equitantleaves

Perennatingstructures

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)• 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

Terrestrial

Orchid growth habits

Epiphytic

velamenOrchid roots

Orchid flower morphology

see Digital Flowers

Orchidaceae

Pollination• function of

column & pollinia

pollinarium

http://www.youtube.com/watch?v=wmgKABRCZpo&feature=related

Richard Dawkins talking about orchid pollination

Comet Orchid(Angraecum sesquipedale)

Morgan’s Sphinx Moth

Endemic toMadagascar

http://www.youtube.com/watch?v=OMVN1EWxfAU

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

YuccaHosta

Agave: bat pollinated Yucca: moth pollinated

Asparagales: Agavaceae

Economic plants and products:

Agave tequila

Asparagales: AgavaceaeEconomic plants and products:

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

Amaryllidaceae diversity

Amaryllidaceae

Hymenocallisspider-lily

Narcissusdaffodil, jonquil, narcissus

Corona sometimes present