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Flowers. Georgia O’Keefe – ‘Two Calla Lilies on Pink’. Tulips. Semper Augustus Tulip. Current Broken Tulip. Queen of the Night Tulip. Wild Rose. Yellow rose – many “petals” are actually modified sterile “petalloid” stamens. Helleborus – five separate carpel s.
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Yellow rose – many “petals” are actually modified sterile “petalloid” stamens
Flower Shapes • regular/ radially symmetrical/actinmorphic – many possible mirror images • irregular/bilaterally symmetrical /zygomorphic - only one mirror image - peas, mints, orchids
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
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
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
Sunflower – Composite head inflorescence
Pollination syndromes among 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
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
Honeybee pollinating beebalm – 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 fly pollinating a composite
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
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
