Phlox Subulata (moss pink) in landscape. Photo © Elaine Mills

Etaerio

etaerio [ EE-tay-ree-oh ] noun: an aggregate fruit formed from multiple ovaries in a single flower

Unlike simple fruits, which develop from a single ovary in a flower, an etaerio develops from multiple ovaries (sometimes called fruitlets) in a single flower arranged over the surface of or within the flower’s receptacle. An etaerio is also called an aggregate fruit. Fruits like achenes, samaras, follicles, berries, and drupes can be simple or aggregated, depending on the plant species.

Etaerio of achenes

an aggregate of one-seeded, dry, indehiscent fruits

Aggregates of achenes of Nelumbo (lotus) — Aggregates of achenes of Nelumbo (lotus) at Green Spring Gardens in July. Photo © Mary Free

Aggregates of achenes of invasive Clematis terniflora — Aggregates of achenes of invasive Clematis terniflora (sweet autumn clematis) in November. Photo © Elaine Mills

Aggregates of achenes of Fragaria (strawberry) — Aggregate of achenes atop a fleshy Fragaria (strawberry) receptacle. Photo © Mary Free

Aggregate of achenes rose hip — Aggregate of achenes within a fleshy receptacle (rose hip) of Rosa sp. in September. Photo © Mary Free

Etaerio of samaras

an aggregate of winged achenes

Aggregated samaras of native Betula nigra — Aggregated samaras of native Betula nigra (river birch) in May with a “cone” beginning to break apart. Photo © Mary Free

Aggregated winged achenes (samaras) of native Liriodendron tulipifera (tuliptree) — Aggregated samaras of native Liriodendron tulipifera (tuliptree) in September.
Photo © Mary Free

Etaerio of follicles

an aggregate of dry, dehiscent, unilocular (containing a single cavity) fruits with two or more seeds formed from a single carpel

Aggregated follicles of Aquilegia canadensis — Immature and dehisced aggregates of follicles of native Aquilegia canadensis (wild columbine) in June.
Photo © Mary Free

Aggregated follicles of Helleborus foetidus — Aggregate of follicles of non-native Helleborus foetidus (stinking hellebore) in March.
Photo © Elaine Mills

Aggregated follicles of Magnolia virginiana — An immature aggregate of follicles of native Magnolia virginiana (sweetbay magnolia) in August.
Photo © Christa Watters

Etaerio of berries

an aggregate of fleshy berries crowded on the receptacle

Aggregates of berries of Annona squamosa (custard apple) — Aggregates of berries of Annona squamosa (custard apple).
Photo by Rushikesh Tade

Etaerio of drupes

an aggregate of fleshy drupes or drupelets

Aggregates of drupelets of Rubus fruticosus 'Chester' (blackberry) — Aggregates of drupelets of Rubus fruticosus ‘Chester’ (blackberry) in July. Photo © Mary Free

Aggregates of drupelets of invasive Rubus phoenicolasius (wineberry) — Aggregates of drupelets of invasive Rubus phoenicolasius (wineberry). Photo © Mary Free

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