Kingdom Plantae: Angiosperms

Flowering plants 2 Classes: Monocots and dicots Flower part # already discussed. Other differences: 1) Cotyledons or seed leaves, first leaflike structure of embryo in seed Monocots with 1 Dicots with 2. 2 cotyledons 1 cotyledon

Flowering plants Other differences: 2) Leaf venation: –Dicots netted venation –Monocots parallel venation

Flowering plants Other differences: 3) Lateral meristems (secondary or lateral growth), making woody stems –Dicots: some do –Monocots: most do not

Flowering plants Summary table: monocots versus dicots

Flowering plants Recap life cycle: pollination brings male gametophyte to stigma of flower.

Pollination syndromes Pollination syndrome is a set of flower features that adapt them to a certain group of pollinating animals Coevolution: when traits of one organism evolve in response to traits of another Here, we characterize floral and animal traits that adapt flowers to particular types of animal pollinators Disclaimer: Note that we must make broad generalizations and exceptions exist to most of the following statements!

Pollination syndromes Bee pollination Bees are: –intelligent –agile –visual animals: good eyesight (including UV light) –good smellers (good sense of smell) –strong (some) –active during day.

Pollination syndromes Bee pollination Bee pollinated flowers are: –Colorful (usually not red) –Have landing platform: place where bee can land on flower as bee does its business –Mildly fragrant.

Pollination syndromes Bee pollination Bee pollinated flowers: –May have nectar guides: patterns of lines or dots that can guide bee to reward –Sometimes these only visible in UV light (which bees see). Petals in visible light (top) and UV (bottom) Orchid flower with nectar guides (lines) on petals

Pollination syndromes Beetle pollination Beetles are: –Relatively clumsy –Have poor vision –Not very smart –Active during the day (many flower-visiting ones).

Pollination syndromes Beetle pollination Beetle pollinated flowers are: –Relatively large or grouped into large inflorescences –Light colored –Smelly (fruity or spicy smell) Inflorescence of Xanthosoma with beetle from it Dogwood inflorescence

Pollination syndromes Bird pollination Birds are: –agile –long-beaked –visual: see red colors well –poor “smellers”: lack good sense of smell Hummingbirds (native to Americas) can hover: don’t need to land to access flower rewards.

Pollination syndromes Bird pollination Bird-pollinated flowers are: red or orange (also yellow), have nectar hidden by long floral tube, little or no fragrance, no landing platform. Aloe Anisacanthus (Acanthaceae) flower

Pollination syndromes Bird pollination: not always by hummingbirds Other birds from other areas: Sunbirds (Africa/Asia) Honeycreepers (Hawai’i). Golden-winged sunbird Iiwi (a honeycreeper) Crested honeycreeper

Pollination syndromes Butterfly pollination Butterflies have: good vision, good sense of smell, long coiled tongue. Must land on flower to visit it (can’t hover). coiled tongue tongue extended

Pollination syndromes Butterfly-pollinated flowers: –Color varies (blue, yellow, orange) –Landing platform present –Nectar at bottom of floral tube Phlox flowersPlumbago flowers

Pollination syndromes Fly pollination Flies have good sense of smell, especially flesh flies Attracted to rotting meat (lay eggs in meat, larvae are maggots).

Pollination syndromes Fly-pollinated flowers: –Smell like rotting meat –Look like rotting meat (dark red, purple) –Offer no reward: flies fooled by flower. Stapelia flower

Fly flower story: Rafflesia Ex, Rafflesia of Sumatra Root parasite Flower is only above-ground part.

Fly flower story: Rafflesia Ex, Rafflesia of Sumatra Largest single flower on Earth.

Pollination syndromes Fly pollination Largest inflorescence is made by fly- pollinated plant Corpse-flower. Inside view

Pollination syndromes Bat pollination Bats are flying mammals –Active at night (nocturnal) –Poor eyesight, good sense of smell –Agile, can hover when visiting flower.

Pollination syndromes Bat pollination Bat-pollinated flowers –Open at night –Produce lots of pollen and nectar as rewards –Are white or light-colored –Are very fragrant (sweet odor) –May be pendant (hang down from branches). Parkia flowers

Pollination syndromes Bat pollination: Mainly a tropical phenomenon In U.S., saguaro cactus is one of few bat-pollinated species. Saguaro flowers Saguaro cactus

Pollination syndromes Moth pollination Moths have: –Poor vision (they are nocturnal) –Excellent sense of smell –Long coiled tongue.

Pollination syndromes Moth pollination Moths: –Some (hawkmoths) can hover when visiting flowers. Hawkmoth

Pollination syndromes Moth pollination Moth-pollinated flowers: –Open at night –Produce lots of sweet fragrance –Are white or light-colored –Make nectar in tube.

Pollination syndromes Interesting moth story: nectar spur Nectar spur is long pouch, at bottom of which is nectar Moth uses long tongue to reach nectar Only if tube is longer than tongue will moth have to push into flower far enough to pick up pollen So, long spurred flowers reproduce better.

Pollination syndromes Which leads to longer moth tongues to reach all of the nectar in the longer tubes Which leads to longer tubes Some moth-pollinated orchids with long nectar spurs (almost one foot long!) Moth has extremely long tongue!

Pollination syndromes Moth pollination Angraecum orchid from Madagascar. Nectar spur almost 1 foot long!

Pollination syndromes Sexual mimics Flowers that mimic female bees or wasps Look/smell like females Males attempt to mate, pick up pollen, then fly to another flower and repeat process No reward supplied!. Sexual mimic orchids

Pollination syndromes Another trick flower Grass pink orchid: grows in pitcher plant bogs in SE US Makes fake stamens on petal. Calopogon orchid (flower made upside down!) Cattleya orchid (flower made right side up) Plant ecology class in bog

Value of Pollinators Native pollinators worth $20-40 billion/yr in U.S. 150 food crops rely on pollinators.

Value of Pollinators Ex, blueberries in Alabama. Honeybees not efficient pollinators. Southeastern blueberry bee very efficient: each bee pollinates $75 worth of berries (visits 50,000 flowers/yr). A SE blueberry bee on the job

Fruits Recall that another unique feature of angiosperms is fruit Fruit: Mature ovary of flower (contains one or more seeds) Exception is parthenocarpic fruits (fruits that do not contain seeds)

Fruits Exception is parthenocarpic fruits (fruits that do not contain seeds) How reproduce? Asexually. Commonly by rooting cuttings. Also tissue culture.

Fruits Ovary wall becomes pericarp in fruit.

Fruits Ovary wall becomes pericarp in fruit Pericarp may develop specialized layers. At most these are: –ectocarp: outer layer –mesocarp: middle layer –endocarp: inner layer

Fruits Major fruit types: 1) Simple fruits: single flower, one pistil 2) Aggregate fruits: single flower, many separate pistils 3) Multiple fruits: many fused ovaries of many flowers.

Fruits Another fruit term: accessory fruit When tissues other than ovary form part of fruit Example: strawberry Receptacle is red part Each small structure on outside is 1 ovary from single small pistil. receptacle Individual small fruits

Fruits Pineapple flowers and fruit Small, pink flowers visible. Each one contributes 1 ovary to fruit

Aggregate Fruits Raspberry, strawberry as aggregate fruits Raspberry Strawberry

Simple Fruits Can be divided into fleshy and dry fruits –Fleshy fruits: Pome: accessory tissue (fused sepals, petals, stamens=hypanthium) makes fleshy part.

Simple Fruits Can be divided into fleshy and dry fruits –Fleshy fruits: Drupe: fleshy outer layer, stony endocarp Ex, peaches, plums, cherries, black walnuts

Simple Fruits Can be divided into fleshy and dry fruits –Fleshy fruits: Berry: pericarp fleshy throughout Ex, Tomatoes, grapes. Muscadine grapes Tomato

Simple Fruits Can be divided into fleshy and dry fruits –Special types of berries: Hesperidium: exocarp leathery, separates from inner layers, fruit divided into sections Orange

Simple Fruits Can be divided into fleshy and dry fruits –Special types of berries: Pepo: exocarp not separating from inner layers, fruit not divided into sections Ex, cucumber, squash, pumpkin.

Simple Fruits Can be divided into fleshy and dry fruits –Dry fruits Dehiscent: Ovary wall breaks apart at maturity Indehiscent: Ovary wall remains around seed at maturity

Simple Fruits Dry dehiscent fruits –follicle: 1 carpel, dehisces along 1 edge

Simple Fruits Dry dehiscent fruits –legume: 1 carpel, dehisces along 2 edges

Simple Fruits Dry dehiscent fruits –silicle/silique: 2 carpels, septum in center of ovary

Simple Fruits Dry dehiscent fruits –capsule: >1 fused carpels, no septum, splits to release seeds. Poppy capsule Cotton “boll” is capsule

Simple Fruits Dry indehiscent fruits –samara: one or more wings (pericarp outgrowths) present wafer ash samarasmaple samaras

Simple Fruits Dry indehiscent fruits –nut: one seed, seed not fused to pericarp –Ex, acorn, chestnut. Acorn in cup Acorns

Simple Fruits Dry indehiscent fruits –achene: one seed, fused to pericarp at one point –Ex, dandelion, sunflower.

Simple Fruits Dry indehiscent fruits –grain (caryopsis): one seed, fused entirely to pericarp –Ex, corn, rice, wheat. rice

Fruit functions 1) Fruit can be protective against: –Seed predators –Environmental conditions

Fruit functions 2) Fruit can promote seed dormancy –Hard endocarp can seal out water/oxygen –Breaking layer called scarification

Fruit functions 2) Fruit can promote seed dormancy –Hard endocarp can seal out water/oxygen –Breaking layer called scarification –Fleshy fruits can contain germination inhibitors (prevent seed from germinating in fruit) –Rotting or digestion by animal gut needed to remove inhibitors so seed will germinate

Fruit functions 3) Fruit can aid seed dispersal –Mechanical dispersal: throws or squirts seeds –Example, fruit of touch-me-not

Fruit functions 3) Fruit can aid seed dispersal –Physical forces dispersal Wind (dandelion) Water (coconut) Dispersing dandelion fruits (achenes)

Fruit functions Fruit can aid seed dispersal –World’s largest seed (inside covering of fruit) –Double coconut palm

Fruit functions Fruit can aid seed dispersal –Biological dispersal Outside body: hooks, barbs, glue Fruits of sandspur (Cenchrus)

Fruit functions Fruit can aid seed dispersal –Devil’s claw (Proboscidea) –Makes fruit with large hooked claws (elongated top of capsule). Devil’s claw fruits) Extinct ground sloth with fruits attached Now?

Fruit functions Fruit can aid seed dispersal –Biological dispersal Inside body: Fleshy fruits (soft, sweet fruits)

Seed coat functions 1) Protect embryo (like pericarp) 2) Promote seed dormancy (like pericarp)

Seed coat functions 3) Aid in seed dispersal –Hairs on some wind-dispersed seeds Hairs on milkweed seeds Cotton is hairs on cotton seeds

Seed coat functions 3) Aid in seed dispersal –Elaiosome on ant-dispersed seeds –Elaiosome: food body on outside of seed coat –Ants collect seed, remove elaiosome, discard seed underground or aboveground. Stylophorum seeds Fremontodendron seeds

Seed coat functions 3) Aid in seed dispersal –Ant dispersal: Common for Eastern forest spring flowering plants. Trillium Trout lily Hepatica Bloodroot Viola