1. Peraceae Klotzsch

    1. This family is accepted.

[NTK]

Esser, H.-J. (2009). Neotropical Peraceae.

Morphology
Description

Trees or shrubs, usually evergreen , lacking latex (rarely yellowish watery exudate reported), without extrafloral nectaries.  Leaves alternate (rarely opposite), simple , margin entire , petiole present, quite short, eglandular, stipules present and scaly to large or (nearly) absent to invisible; indumentum of simple , T-shaped, stellate or lepidote hairs; venation pinnate , veinlets reticulate to percurrent. Inflorescences unisexual (rarely bisexual ), dioecious (rarely monoecious ), axillary , fasciculate -glomerulate, sometimes surrounded by two fused spathaceous bracts, or elongate raceme -like to paniculate; bracts otherwise small, inconspicuous. Flowers actinomorphic , pedicellate to subsessile, with imbricate , free to mostly fused sepals or without, petals free or absent. Staminateflowers with 4-6 free sepals or calyx fused with 2-4(-6) lobes, or without, with 5 free petals or without, stamens (2-)5-20, filaments free or connate at base, anthers dorsifixed or basifixed, extrorse to introrse, bilocular , opening with longitudinal slits, pollen 3-colporate, tectate to perforate-tectate, exine rugulose to psilate, disc consisting of separate glands , fused, or absent, pistillode present, sometimes surrounding staminate flowers and therefore then being a reduced flower itself.  Pistillate flowers with 4-6 free sepals or without, with 5 free petals or without, without staminodes, disc entire to cupular or absent, ovary hypogynous, syncarpous, with 3 locules , glabrous to pubescent and sometimes echinate - spiny , ovules 1 per locule , placentation axile , anatropous, bitegmic, style short to absent, stigmas 3, bilobed and fimbriate or peltate - discoid . Fruits septicidally dehiscent schizocarps with 3 seeds, echinate - spiny or smooth. Seeds ellipsoid to ovoid , smooth and conspicuously shiny black, anatropous, carunculate, without sarcotesta, endosperm copious, embryo with flat cotyledons broader than radicle. Chromosome numbers not reported.

General Description
Notes on delimitation
  • The family had been accepted as distinct by a few authors in the past, and was then treated as part of Euphorbiaceae for a long time.  It has been re-established mainly by recent molecular phylogenies, but is also supported by some unusual characters of the fruits and seeds (APG III). Peraceae are therefore sufficiently well defined as a taxon; the status as separate family or as a basal part of Euphorbiaceae is still viewed differently by some authors.  Characters of, among others, wood anatomy and pollen agree mostly with Euphorbiaceae.
Number of genera
  • See under Notable genera.
Status
  • Native - Chaetocarpus Thwaites, Pera Mutis, Pogonophora Miers ex Benth. (the latter two being endemic).
Distribution
Distribution in the Neotropics

Peraceae are pantropical with 5 genera and ca. 120-130 species. Of these, 3 genera and ca. 50 species are Neotropical, mostly occurring in tropical lowland evergreen rainforests.

  • Chaetocarpus Thwaites: pantropical with ca. 15 species, 9 of which are Neotropical in the Antilles and from Venezuela to Bolivia.
  • Pera Mutis: ca. 40 species from S Mexico to the Antilles and Bolivia, with numerous endemics in particular on Cuba.
  • Pogonophora Miers ex Benth.: one species (P. schomburgkiana Miers ex Benth.) in the rainforests of the N Amazon (Colombia to the Guianas), two species of somewhat doubtful affinity in W Africa.
Diagnostic
Other important characters
  • Hairs T-shaped or stellate-lepidote (simple only in Chaetocarpus).
  • Infloresences many-flowered but often small and fasciculate.
Distinguishing characters (always present)
  • Dioeciouswoody plants (very rarely reported as monoecious).
  • Leaves simple, entire and completely eglandular.
  • Small unisexual flowers in axillary inflorescences.
  • 3-locular ovaries with one anatropous ovule per carpel.
  • Fruits with 3 conspicuously shiny black seeds, the mericarps splitting regularly from the top but often remaining attached at the base.
  • Testa of the seeds with a tracheoidal exotegmen.
Key differences from similar families
  • Peraceae share simple leaves, small unisexual flowers and 3-locular septicidal schizocarps with several families. They differ in the following characters from:
  • Euphorbiaceae - leaves completely eglandular, fruits dehiscent but often not dehiscing completely, seeds conspicuously shiny and black.
  • Phyllanthaceae -  fruits with one seed per carpel, seeds conspicuously shiny and black.
  • Putranjivaceae - plants without glucosinolates, leaf base not oblique, fruits dehiscent with 3 seeds, seeds conspicuously shiny and black.
Notable genera and distinguishing features
  • Chaetocarpus - hairs always simple, flowers apetalous, stamens with the filaments fused at base, ovaries and fruits echinate -spinose.
  • Pera - hairs stellate-lepidote, inflorescences with spathaceous connate bracts completely enclosing the buds, flowers apetalous, stamens with the filaments fused at base, ovaries and fruits smooth to wrinkled but never echinate.
  • Pogonophora - hairs simple and T-shaped, flowers with regular calyx and corolla, stamens free, fruits smooth.
Literature
Important literature

Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A. 2000. World checklist and bibliography of Euphorbiaceae (with Pandaceae). Royal Botanic Gardens, Kew.

Radcliffe-Smith, A. 2001. Genera Euphorbiacearum. Royal Botanic Gardens, Kew.

Secco, R. 1990. Revisão dos gêneros Anomalocalyx Ducke, Dodecastigma Ducke, Pausandra Radlk., Pogonophora Miers ex Benth. e Sagotia Baill. (Euphorbiaceae -Crotonoideae) para a America do Sul. Belém: Museu Paraense 'Emilio Goeldi'.

Webster, G.L. 1994. Classification of the Euphorbiaceae; Synopsis of the Genera and Suprageneric taxa of Euphorbiaceae. Ann. Missouri Bot. Gard. 81(1): 3-32, 33-144.

Wurdack, K.J. & Davis, C.C. 2009. Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiospermtree of life. Amer. J. Bot. 96(8): 1551-1570.

Images

Peraceae Klotzsch appears in other Kew resources:

First published in Monatsber. Königl. Preuss. Akad. Wiss. Berlin 1859: 241, 246. (1859)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
[A] © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
[B] http://creativecommons.org/licenses/by/3.0