What are the types of Racemose inflorescence?
Simple racemose inflorescence is of following types.
- Raceme: Here pedicellate flowers are present on peduncle. E.g Delphinium (Larkspur, Raphanus (Radish), Mustard. For More Biology Doubts check out our biology doubts section.
- Spike: Here sessile flowers are present on peduncle. e.g Callistemon (Bottle brush), Amaranthus, Achyranthus, Adhatoda.
- Spadix: Here peduncle is thick and fleshy with upper part sterile and lower part bearing one or both the types of unisexual flowers, surrounded by a large brightly coloured bract called spathe e.g: Colocasia (Arum), Arisaema. In maize, the female flowers develop in a spadix.
- Catkin (or Amentum): It is pendulous spike which bears female or male flowers but not both. e.g Mluberry.
- Strobile: It is like spike inflorescence but flowers develop in the axils of persistent membranous bract. e.g Humulus (Hop)
- Here main axis is comparatively short.
- Upper flowers have much shorter pedicel than the lower ones, so that all the flowers are brought more or less to the same level. g : Iberis amara (Candytuft)
- Inflorescence appears like corymb near the growing point.
- It appears like raceme lower down.
Pedicel of the upper flower is shorter as compared to lower flower.
Ex: Brassica campestris (Mustard)
- Here peduncle is shortened
- All flowers have pedicel of equal length.
- All the flowers arise from a single point, like the ribs of an umbrella.
At the base of pedicel, there is a whorl of bracts forming an invoucre.
g Allium cepa (Onion), Hydrocotyle asiatica
- Peduncle is flattened called receptacle.
- A large number of sessile flowers are borne on the receptacle.
- Two kinds of florets can be recognized on receptacle.
- Ray florets
These are female or sterile, zygomorphic, arranged in one or more whorls
on the rim of receptacle
Disc florets: These are bisexual, actinomorphic present at centre.
e.g. Sunflower, Marigold