Flowers
Tulips
Semper Augustus Tulip
Current Broken Tulip
Queen of the Night Tulip
Wild Rose
Yellow rose – many “petals” are actually modifiedsterile “petalloid” stamens
Helleborus – five separate carpels
Malus – crab apple – typical flower structure
Flower Shapes
• regular/ radially symmetrical/actinmorphic - mirror images
• irregular/bilaterally symmetrical /zygomorphic - only one mirror image - peas, mints
Flower Shapes
Regular/Actinomorphic Irregular/Zygomorphic
Flower Sexuality, etc.
• monoecious - separate flowers for male and female both on one plant – corn
• dioecious - male and female plants are separate - separate sexes - gingko
• Perfect flower - flower has stamens and carpels – bisexual flowers
• Imperfect flower - lacks either stamens or carpels - will be staminate or carpellate (pistillate)
• Complete - has sepals, petals, stamens and carpels
• Incomplete - lacking one of the 4 main flower parts
Jatropha – monoecious but insect pollinated
Willows - Dioecious
Complete Flower
Incomplete Flower – Panic Grass
Inflorescence
• Often flowers, especially small flowers, are gathered into a structure known as an inflorescence – an aggregation of flowers on a single flowering branch
• Bract - more or less modified leaf that subtends flower or inflorescence- bract can look like normal leaf
• Bract can also look like petal - petaloid
Dogwood with petalloid leafy bracts
Types of Inflorescence
1. Racemous or indeterminant - youngest flower at apex - in theory could produce flowers forever - some may by fruiting while apex still flowering - include - racemes, panicle, spike, corymb, head, umbel, catkin
2. Cymose or determinant - oldest flowers at apex - moving down younger flowers - cyme, scorpiod cyme
Larkspur inflorescence – a raceme
Wild parsnip – umbel inflorescence
Sunflower – Composite head
inflorescence
Borage Inflorescence – A scorpiod cyme
Skunk cabbage inflorescence – with spathe and spadix
Pollination syndromesamong the phloxes
Beetle Pollination• Several modern plant species are pollinated largely or exclusively by
beetles - beetles were probably the first important group of insect pollinators
• Beetle flowers - large, borne singly - Magnolia, some lilies, California poppies, and wild roses
• or small and in inflorescence - dogwood, elders, parsley
• Beetles have quite a well-developed sense of smell and their flowers are often quite odoriferous - fruity, spicy or foul odors such as from fermentation
• Flowers often white or dully colored
• Often produce large amounts of pollen, some produce a little nectar, beetles chew directly on petals of some
Magnolia – beetle pollinated
Bee and Wasp Pollination• Most important group of flower pollinators
• Bees and wasps have mouthparts, body hairs and other appendages that allow them to efficiently collect and carry pollen and nectar
• 20,000 species of bees - most pollinate flowers
• Bees highly visual - don’t see red, but do see ultraviolet as a color
• Bee flowers - typically have showy, brightly colored petals, often blue or yellow - never pure red
• Have patterns called nectar guides which direct bees to pollen and nectar - often in UV color
• Nectaries usually at base of corolla tube, produce large amounts of nectar, concentrated nectar - up to 70% sugar
• Petals often have landing platform for bees
Honeybee covered with
pollen
Scotch broom – bee pollinated
Honeybeepollinatingbeebalm –
Monarda sp.
With visible light with UV light
Nectar guides for honeybees
Fly Pollination
• can flower during day or night• color highly variable, but will be purple-brown or
greenish for carrion and dung flies• often very strong odors – smelling of decay for
carrion flies• usually fairly open flowers, but some have deep
traps to keep flies inside for a night• usually no reward but some provide pollen or
nectar
Cyrtid flypollinatinga composite
Caralluma – carrion fly pollinated
Butterfly and Moth Pollination
• Butterfly and moth flowers similar to bee flowers because moths and butterflies also guided to flowers by combination of sight and smell
• Some butterflies can see red, so often have red or orange color for flower
• Nectary is often at bottom of long, slender corolla tube or a nectar spur - only accessible to long sucking probocis of moths and butterflies
• Nectar is copious, but not so concentrated - often 25% sugar• Moths are nocturnal so many of their flowers emit heavy
fragrance at night, often pale or white in color - scent is sweet and penetrating
Erysimum – butterfly pollinated
Episcia – moth pollinated
Bird Pollination
• Bird pollinated flowers produce copious, thin nectar - often about 25% sugar, often very high in sucrose - may actually drip with nectar
• Usually have little odor because birds have poor sense of smell
• Birds see red and bird pollinated flowers often very colorful with reds and yellows - red columbine, fuchsia, passion flower, hibicus, poinsettia, many cactus and orchids
• The flowers are usually large or part of large inflorescence
• Nectar usually held in long tubes that other animals can’t reach
Hummingbird pollination
Ipomopsis aggregata – hummingbird pollinated
Greater double-collared sunbird
Proteus – pollinated by perching birds
Bat Pollination
• About 250 species of bat (25%) include some pollen, nectar or fruit in their diet - many pollinate flowers as part of their feeding
• Bat flowers are similar to bird flowers - large, strong flower which produces copious nectar - Often dull colored because open at night - may only open at night
• Often have very strong fermenting or fruitlike odors, may be musky odors too
• Bat flowers often hang down below foliage to enable bats to easily get to the flower
• Banana, mango, sisal and kapok flowers pollinated by bats
Bat pollination
Wind Pollination• Usually have dull colors, relatively odorless, do not produce nectar, petals
small or absent, sexes often separated• Wind pollinated flowers are most common in temperate areas where large
stands of single species of plant occur• With trees, wind pollination occurs in spring before leaves have emerged -
usually have well exposed stamens to shed pollen to wind and stigma also exposed - often with feathery outgrowths to catch pollen
• Often the plants have various mechanisms to promote out-crossing - separate sexes - dioecious - willows, poplars
• unisexual flowers on same tree - monoecious - oaks, birches• Self-incompatible - grasses• Flowers are typically small, have single ovule per flower - however have
many flowers borne in inflorescences and multiple inflorescences
Box elder – wind pollinated – female left, male right
Wild oats – Whole plant
Wild oat flower – close up
Cottonwood Catkins
Male Female
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