Botanical Inflorescence Types: Cymes, Scorpioid Cymes, Helicoid Cymes & Fruit Morphology

Determinate (Cymose) Inflorescences

In cymose inflorescences, the terminal flower blooms first, halting apical growth. Lateral buds continue the pattern. Key forms:

Monochasium (Single Lateral Branch)

• Scorpioid cyme (cincinnus): Successive branches alternate on one side → coiled "scorpion tail" appearance. Typical of Boraginaceae (Myosotis, Borago, Heliotropium).
• Helicoid cyme (bostryx): Branches alternate right/left in one or two planes. Example: Hemerocallis (daylily).

Dichasium (Two Lateral Branches)

• Opposite pairs at each level → panicle-like overall form. Typical of Caryophyllaceae and Gentianaceae.
• Variants: pauciflorous (few flowers) vs. multiflorous (many).

Polychasium (Multiple Laterals)

• Three or more branches per node (e.g., some Euphorbiaceae).

Specialized Monochasial Forms

• Drepanium: All branches in one plane.
• Rhipidium: Unifloral branches in one plane, axes curved back. Typical of Iridaceae (Iris germanica).

Fruit Morphology Note

Cynorrhodon (hip): False fruit—swollen, cup-shaped floral receptacle (hypanthium) enclosing true fruits (achenes). Classic example: rose hip. Though fleshy, the edible tissue is receptacular, not ovarian.

Understanding inflorescence architecture aids species identification, breeding decisions, and ecological interpretation.