Detailed Inflorescence Morphology
Summary:
Inflorescence morphology encompasses the arrangement and structure of flowers on the floral axis, providing essential insights into plant reproduction. The key components of inflorescence include the peduncle (stalk), rachis (floral axis), and pedicel (stalk of individual flowers). Flowers with pedicels are termed pedicellate, while those lacking are termed sessile.
Inflorescences primarily fall into three categories:
- Indefinite/Racemose Inflorescence: Also known as botryose, this type features a primary floral axis (rachis) that doesn’t terminate with a flower. Instead, it continues growing, producing flowers laterally in an acropetal manner (oldest at the base, youngest at the apex). Several subtypes exist:
- Raceme: Elongated rachis bearing pedicellate flowers opening from base to apex.
- Corymb: A raceme with unequal pedicel lengths.
- Spike: Similar to a raceme but with sessile flowers.
- Amentum/Catkin: A spike of unisexual flowers with a drooping peduncle.
- Spadix: A modified spike with a fleshy rachis and a spathe covering the inflorescence.
- Locusta/Spikelet: A condensed spike with bracts called glumes, found in grasses.
- Strobile: A modified spike with persistent, membranous bracts bearing pistillate flowers.
- Definite/Cymose Inflorescence: In this type, the primary axis growth is terminated by a flower, with younger flowers occurring below it. Variations include:
- Solitary Terminal/Axillary Flower: A single flower develops from the apical or axillary bud.
- Monochasium/Uniparous Cyme: The primary axis ends in a flower, and lateral branches consecutively produce more flowers.
- Dichasium/Biparous Cyme: The primary axis terminates in a central flower that opens first.
- Polychasium/Multiparous Cyme: The primary axis produces more than two lateral branches in a whorled manner.
- Condensed Cymose Inflorescence: Examples include cyathium, verticillaster, hypanthium, Coenanthium, and cymose head.
- Mixed Inflorescence: Combines elements of racemose and cymose types or may involve two racemose types—for instance, the sunflower and dahlia exhibit mixed inflorescences.
Excerpt:
Detailed Inflorescence Morphology
Definition:
Inflorescence or anthotaxy is the branch or branch system bearing flowers or the arrangement of flowers on the floral axis. The stalk of the inflorescence is known as the peduncle. The floral axis of an inflorescence-bearing flower is called the rachis, and the stalk of the individual flower is known as the pedicel.
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