Flowers and Fruit
Flower Structure
• Generalized flowers - 2 outer sets of sterile parts, 2 inner sets of fertile parts
• Outer sterile part - sepals, collectively the calyx - may do photosynthesis, protect flower, usually like leaves in texture, protect bud - form outer covering of bud
• Next sterile part - petals - not like leaves in texture, usually not green, collectively called corolla - petalloid - petal like in appearance
• Both sepals and petals can be fused - so sepals joined together, petals joined together
• Perianth - calyx and corolla together - used when the two cannot be distinguished - sometimes sepals and petals are called tepals for perianth if very similar in appearance – like in Tulips
• If only one set of sterile parts, they are always called sepals; sometimes whole perianth is missing
• First fertile parts - stamens - male – androecium - Can be sterile and modified to look like petals
• Innermost fertile parts - pistils, female - gynoecium
Yellow rose – many “petals” are actually modifiedsterile “petalloid” stamens
Carpels and Ovaries
• Flowering plants always have enclosed ovary wrapped in a carpel - nonflowering plants don't - this is the vessel of the angiosperm
• Carpel is highly modified leaf - a simple pistil is one ovary
• Pistil may be made up of one carpel or several fused carpels
• Often the bottom part called the ovary, with stigma at top to receive pollen, style connects them - fused carpels may have separate style and stigma or they may all be fused
Helleborus – five separate carpels
Malus – crab apple – typical flower structure
Plant Sexuality
• 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
Complete and Incomplete Flowers
Jatropha – monoecious but insect pollinatedFemale left, male right
Dioecious - Holly
Female flower Male flower Berries on female
Inflorescence terms
• 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 flower groups - bract can look like normal leaf
• bract can also look like petal - petalous - dogwoods have big white "petals" that are really petaloid bracts
• peduncle - stalk of cluster of flowers• pedicel - stalk of individual flower• petiole - leaf stalk
Dogwood with petalloid leafy bracts
Types of Inflorescence
1. 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. determinant - oldest flowers at apex - moving down younger flowers - cyme, scorpiod cyme
Raceme
Larkspur
Panicle
Panicum - switchgrass
Spike – prairie blazing star
Corymb
Umbel
Wild parsnip Queen Anne’s Lace
Sunflower – Composite headinflorescence
Catkin
Alder catkin
Scorpoid Cyme
Onosmodium
Skunk cabbage inflorescence – a spathe and spadix
Pollination syndromesamong the phloxes
Magnolia – beetle pollinated
Honeybee covered withpollen
Scotch broom – bee pollinated
Honeybeepollinatingbeebalm –Monarda sp.
With visible light with UV light
Nectar guides for honeybees
Cyrtid flypollinatinga composite
Caralluma – carrion fly pollinated
Erysimum – butterfly pollinated
Episcia – moth pollinated
Hummingbird pollination
Ipomopsis aggregata – hummingbird pollinated
Greater double-collared sunbird
Proteus – pollinated by perching birds
Bat Pollination
Box elder – wind pollinated – female left, male right
Wild oats – Whole plant
Wild oat flower – close up
Fruit Types
• A fruit may be defined as a matured ovary • There are two basic fruit types – dry or
fleshy. These types arise from the development of the pericarp
• The pericarp may become dry and these form dry fruits
• The pericarp may also become soft, thick and fleshy – and these form fleshy fruits
Apples and Pears
Violetflowertypes