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Incoming links: Cypsela in the New York Botanical Garden Lecythidaceae glossary
Cypsela 2026-11-05
A cypsela is a dry, one-seeded indehiscent fruit derived from an inferior ovary, especially characteristic of Asteraceae. The seed remains enclosed by a fruit wall rather than being the whole structure. In the narrower terminology distinguishing it from an achene, a cypsela has an inferior, origin in two carpels.[ref]
Cypsela in the New York Botanical Garden Lecythidaceae glossary. Definition: inferior bicarpellate ovary and Asteraceae
A pappus, when present, forms a crown or plume associated with the cypsela. It comes from the modified calyx, whereas the seed comes from an ovule. These parts can travel together during seed dispersal while retaining different developmental origins.[ref]
Cypsela in the New York Botanical Garden Lecythidaceae glossary. Pappus identified as modified calyx
To see the distinction, imagine removing the enclosing wall of one mature unit: the enclosed seed is a separate anatomical object. Calling the whole unit a seed hides that extra layer. Some floras use achene broadly enough to include these fruits, so the convention of the identifying flora should be checked.[ref]
Glossary of Botanical Terms by PlantNET. Entries achene and cypsela; Figure18Q–R distinguishes superior- and inferior-ovary origins
Pappus 2026-11-05
A pappus is a modified calyx, especially in Asteraceae, that can form hairs, bristles or scales associated with the mature fruit. In a wind-carried Taraxacum unit, the plume is the pappus, the enclosing fruit is a cypsela, and the seed lies inside. These structures travel together during seed dispersal but have different developmental origins.[ref]
Cypsela in the New York Botanical Garden Lecythidaceae glossary. Cypsela definition and modified calyx
The plume also supplies an unusually clear connection between plant morphology and fluid mechanics. In 2018, Cathal Cummins and collaborators used a vertical wind tunnel and laser-sheet flow visualization to investigate air behind freely flying and fixed Taraxacum units. A vortex ring remained separated from the porous plume. Comparisons with fabricated disks of different porosity helped test how an open structure could stabilize this flow pattern.[ref]
A separated vortex ring underlies the flight of the dandelion by Cathal Cummins and others. Methods M1A; supplementary videos1–5
Thus a pappus is not simply a miniature solid parachute: air can pass through the spaces between its filaments. The experiment made that invisible motion observable. Its result concerns the studied Taraxacum geometry and flow conditions; not every bristly pappus has the same aerodynamic behavior.