Rosaceae: Prunoideae - drupes

BOT 360F - Families of Vascular Plants

Drupes are fleshy fruits in which the inner part of the ovary wall becomes a hard and woody pyrene, while the outer part remains soft and may be invested with sugars and water, or with lipids. These nutrients may serve as food rewards for potential animal dispersal vectors, i.e. they may represent adaptations for endozoochory. Not all drupes are fleshy and associated with endozoochory; coconuts are just as much drupes as dates are.

Most members of Rosaceae subfamily Prunoideae produce drupes that develop from the single pistil of a perigynous flower, as shown below. An exception is the genus Oemleria (osoberry), from the Pacific northwest, in which up to five pistils are found within the hypanthium. The largest genus in the subfamily is Prunus L. (cherries, plums, peaches, apricots, almonds). The "pome" fruits that develop from the hypanthial ovaries of some members of subfamily Maloideae are technically also (polypyrenous) drupes.

Prunus virginiana - 17453 Bytes

Photo: M. Ferguson 1998 Royal Ontario Museum

Prunus flower and fruit - Strasburger et al. 1898 - 29823 Bytes

Prunus nigra (Canada plum)

Photo: R. Presgrave 2000 Royal Ontario Museum (TRT1824)

Prunus virginiana (chokecherry) - racemes of drupes, each of which develops from the single pistil found at the center of the hypanthial cup (diagram above).

Flower and fruit illustrations from Strasburger et al. (1898) A textbook of botany; compare Judd et al. Fig. 8.74).



Mulligan, G. A. & D. B. Munro, 1981. The Biology of Canadian Weeds 51. Prunus virginiana L. and P. serotina Ehrh. Can. J. Plant Sci. 61: 977-992. [includes key to species native to Canada]

Images from Botany at the University of Hawaii

Note: Use your browser's BACK function to return to the course pages from this image.

| What are plant families? | How do we distinguish them? | How and why do we study them? | Selected vascular plant families of Ontario | Reading List | Course outline |

|EEB337H1 Home Page | What's New | U of T Ecology & Evolutionary Biology | University of Toronto |

© 2008 Department of Ecology & Evolutionary Biology and 2000-2006 Botany Department, University of Toronto.

Please send your comments to; last updated 17-Nov-2008