FLOWER IDENTIFICATION KEY – corolla and calyx
Examine the corolla – is it made up of ‘free’ petals or ‘fused’ petals and what shape is it? There are 5 ‘free’ petal shapes and 8 ‘fused’ petal shapes below.
Examine the sepals to see if they are fused into a calyx tube, an example is shown below.
To learn more about the Corolla and Calyx click HERE
20 families have species with free petals and an open arrangement as shown by this poppy but some families have flowers with free petals that are arranged in a complex way to make access by pollinators to nectar more difficult.
The ‘Pea’ flower has 5 free petals, a ‘banner’ , consisting of 2 petals which encloses the flower before it opens, 2 ‘wing’ petals and one ‘keel’ petal.
The ‘Iris’ flower has 3 outward, downward-curving ‘falls’ and 3 inner, usually upright ‘standards’ which act to attract pollinators whilst the ‘falls’ act as insect landing sights.
The Orchid flower has 6 tepals in two whorls. The outer layer has 3 equal size ‘sepals’, the inner layer 3 ‘petals’. The central inner ‘petal’ called the labellum, is enlarged and has 3 lobes.
Violet and Buttercup families have some species with individual petals that extend into spurs.
Botanists have developed a number of terms to describe corollas and calyx tubes formed from ‘fused ‘ petals or sepals. The shapes have evolved to make access to certain parts of the flower more difficult. 9 of these shapes are illustrated here.
Salverform – tube opens to a flat plate or salver
Phlox, Sea Lavender, Primrose and Periwinkle
Funnelform – tube opens up to a funnel entrance
Convolvulus, Borage, Nightshade and Honeysuckle
Personate – 2-lipped with a closed mouth. Plantain family
Rotate – Short tube then spreading like a wheel
Iris, Phlox,Primrose, Borage, Nightshade and Plantain families
Campanula – Bell-shaped
Bellflower, Plantain, Nightshade, Saxifrage and Asparagus families
Mint, Figwort, Bellflower (Lobelias), Honeysuckle families
Urceolate – Urn-like
Tubular – cylindrical and hollow
Iris (Crocosmia), Asphodel (Red-hot Poker) families
Calyx Tube – tube formed from fused sepals
Pink, Loosestrife, Willowherb families