Jon L.R. Every
University of Plymouth, U.K.
Trees, deciduous. Leaves alternate, simple, lamina leathery, margins entire, tri-nerved, large pit on the underside in each axil of basal lateral veins; pulvinate at both ends of petiole; stipules present, intrapetiolar, caducous (leaving prominent scars). Inflorescence axillary racemes (Peridiscus Benth.) or fascicles (Whittonia Sandwith), bracteoles large and persistent. Flowers regularly symmetrical, bisexual; sepals 4-5(-6) (Peridiscus) or 7 (Whittonia), imbricate, reflexed when open; apetalous; stamens numerous; ovary superior, syncarpous, half immersed in disc and glabrous (Peridiscus) or woolly and on top of disc (Whittonia); carpels 3-4; styles 3(-4), free, ovules 6-8, pendulous. Fruit drupaceous (unknown in Whittonia). Seed 1 per fruit.
Notes on delimitation
- This little known family is currently assigned to the Saxifragales (APGIII).
Distribution in the Neotropics
- Collected in both Brazil and the Guianas.
Distinguishing characters (always present)
- No petals.
- Stipules leave prominent scars.
- Leaves alternate.
- Leaf with three main veins.
- Pulvinus at both top and bottom of petiole.
- Large, persistent bracteoles.
- Sepals imbricate.
- Disk present.
Other important characters
- Fruit only known from Peridiscus.
Number of genera
- Two of the family's three genera have been collected in the Neotropics, both of which are monotypic: Peridiscus lucidus Benth and Whittonia guianensis Sandwith.
APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society 161(3): 105-121.
Heywood, V.H.H. 2007. Peridiscaceae. In: V.H. Heywood, R.K. Brummitt, A. Culham and O. Seberg (eds.). Flowering plant families of the world. P. 249. Royal Botanic Gardens, Kew.
Mabberley, D.J. 2008. Mabberley's plant book. Third edition. Cambridge University Press, Cambridge.
How to cite
Every, J.L.R. (2010). Neotropical Peridiscaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Peridiscaceae.htm.