• Spadix - is the characteristic inflorescence of the remarkable arum family (Araceae). - It consists of a thickened, fleshy axis (spike) bearing clusters of sessile, apetalous, unisexual flowers. - The small unisexual flowers are packed together along the lower region of an erect, phallus-like central spike, typically with male flowers above the female. - The upper region of the spadix is usually devoid of flowers. - Male (staminate) flowers consist of numerous stamens packed together,
- while female (pistillate) flowers consist of numerous individual pistils. - Individual flowers are reduced to a single stamen or pistil (gynoecium). - The spadix emerges from a vase- shaped or funnel-like modified leaf or spathe which is often brightly colored. - The spadix of some arums emits a putrid odor that attracts carrion flies for pollination.
• Raceme - This inflorescence has an unbranched main axis and all the pedicels of the flowers are more or less the same length.
Other RacemeSweet pea (Lathyrus odoratus) Chinese hat (Holmskioldia sp.)
• Umbel - The peduncle of this type of inflorescence bears all of the pedicels at its apex.Hydrangea (Hydrangeamacrophylla) Lantana (Lantana sp)
• Compound Umbel - The peduncle bears a number of primary pedicels at its apex. These do not bear flowers but a number of secondary pedicels at their apices which in turn bear the flowers. Frangipani (Plumeria rubra)
• Spike - This inflorescence type has a long, unbranched main axis which bears flowers which have no pedicels or very short Silver oak (Grevillea robusta) pedicels.
Quiver tree (Aloe dichotma) Red hot pokerGladiolus (Kniphofia sp.)(Gladiolus sp.)
• Head (capitulum) - which do not have pedicels - are grouped together on the top of a peduncle which may be flattened or rounded. - Daisies (Asteraceae) are a good example - outer flowers may have one very large petal - In other families the whole inflorescence may be surrounded by bracts e.g. the Proteas. - This gives the impression that the whole structure is a single flower but it may infact be hundreds of flowers grouped together.
Examples: King protea (Protea Daisy species cynaroides)
• A Corymb - The main axis of this inflorescence type is elongated and unbranched as in a raceme, but the pedicels of the flowers are of unequal length so that the entire structure appears flat-topped. Examples include hawthorn, the apple and Crataegus calpodendron dogwood.
Hydrangea corymb (group ofHawthorn flowers displayed as a disc)