the monocots: part 1 overview, basal, and “petaloid” groups spring 2011
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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 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 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 and two whorls of stamens
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• Family not required, but Acorus
evolutionarily important
“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 (specialized leaf)
• Special uses: many ornamentals; Colocasia as food
• Required taxa: Arisaema, Lemna
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: 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
“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
Erythroniumtrout-lily
-bulbs ovate to elongate-scapose herbs with 2 leaves (1 if non-flowering)-tepals 6, spreading to reflexed-native wildflowers
Tulipa-scapose herbs from tunicate bulbs-leaves 2-several on a stem-perianth campanulate to cuplike -tepals 6, erect-stigma prominently 3-lobed
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
“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
Agave (L) vs. Yucca (R)
• Perianth tubular-funnelform, 6-parted
• Stamens exserted beyond the perianth, anthers versatile
• Ovary inferior• Capsule loculicidal• Bat-pollinated
• Perianth of 6 flat, free tepals
• Stamens shorter than the tepals, anthers basifixed
• Ovary superior• Fruit indehiscent
(berry-like) or septicidal capsule
• Moth-pollinated
Agavaceae: Hosta-rhizomatous, scapose perennials-leaves with a distinct petiole-perianth tubular-funnelform, white, bluish or lavender-stamens 6, epipetalous or hypogynous
-fruit a loculicidal capsule
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
“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
Hymenocallisspider-lily
Narcissusdaffodil, jonquil, narcissus
Corona sometimes present
Narcissus
-scapose, perennial herbs from bulbs-perianth of 6 basally connate tepals, yellow and/or white-cuplike to trumpetlike corona present-stamens 6, epipetalous
Amaryllidaceae: Hippeastrum
-perennial, scapose herbs from large bulbs-perianth of 6 basally connate tepals, white to pink to salmon or red-corona minute-stamens 6, epipetalous
“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
Iris
-rhizomatous herbs-leaves equitant, in a fan-spathes 2-style branches broad, petaloid, terminating in paired crests anthers appressed to style branches
“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
http://www.youtube.com/watch?v=wmgKABRCZpo&feature=related
Richard Dawkins talking about orchid pollination
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