Neotropical Putranjivaceae

Hans-Joachim Esser

Botanische Staatssammlung München, Munich, Germany. 

Description

Trees or rarely shrubs, lacking latex and extrafloral nectaries. Leaves alternate, often distichous, simple, base usually slightly to distinctly unequal (oblique), margins entire to (spinose-)dentate or crenulate, petiolate, short, eglandular, stipules present but caducous, eglandular, scaly, latex absent, indumentum simple, venation pinnate, brochidodromous. Inflorescences unisexual, dioecious to rarely polygamo-dioecious or monoecious, axillary or on older leafless nodes or cauliflorous, fasciculate-glomerulate or (pistillate) flowers sometimes solitary, sessile; bracts small, inconspicuous. Flowers actinomorphic, pedicellate, with 4-5(-7) imbricate, free to nearly free, often unequal sepals, petals absent. Staminate flowers with 4-12 stamens, filaments free, anthers basifixed, introrse to rarely extrorse, bilocular, opening with longitudinal slits, disc intrastaminal, flat, entire to variously lobed, pollen 3-colporate, tectate, psilate, or lalongate, pistillode minute or absent. Pistillate flowers without staminodes, disc annular or cupulate (rarely absent), ovary hypogynous, syncarpous, with 1-2(-3) locules, usually pubescent, ovules 2 per locule, placentation axile, anatropous, bitegmic (very rarely unitegmic), style short to absent, stigmas 1-2(-3), short thick and flattened, entire or sometimes bifid. Fruits indehiscent, drupaceous, globose to ovoid-ellipsoid, exocarp and mesocarp leathery to fleshy, endocarp crustaceous, usually 1-seeded by abortion (sometimes 2-seeded); seeds ellipsoid to globose, smooth, anatropous, ecarunculate, sarcotesta when present thin, endosperm copious, embryo straight, cotyledons broad. Chromosome number usually 2n = 40.

Notes on delimitation

  • The Putranjivaceae were included in the Euphorbiaceae subfamily Phyllanthoideae [now Phyllanthaceae] for a long time, but were recognized as unusual there because of, among others, the presence of glucosinolates, the unusual fruits and different chromosome base numbers.

Distribution in the Neotropics

  • The Putranjivaceae are represented by one genus in the Neotropics, occurring in several vegetation types but usually in tropical moist forests: Drypetes Vahl - a pantropical genus with 21 species in the Neotropics.
  • In the New World the majority of species are Caribbean.

Distinguishing characters (always present)

  • The single genus is characterized morphologically by
    - simple leaves that are nearly always unequal (oblique) at their base
    - unisexual flowers in axillary glomerules (or solitary pistillate flowers)
    - indehiscent drupaceous and usually pubescent fruits with 1 or (more rarely) 2 seeds.
  • The Putranjivaceae also contains glucosinolates (mustard oil glycosides).

Other important characters

  • Dried leaves are often of a greyish colour.
  • Fresh bark and leaves often have a taste of pepper or radish.

Number of genera

  • Putranjivaceae are pantropical and comprise ca. 4 genera. In the Neotropics they are represented by 1 genus: Drypetes

Status

  • Native - Drypetes.

Important literature

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

Pax, F. & Hoffmann, K. 1922. Drypetes. In: E. Engler (ed.), Das Pflanzenreich IV.147.xv (Euphorbiaceae -Phyllanthoideae-Phyllantheae): 229-279. W. Engelmann, Leipzig.

How to cite

Esser, H.-J. (2009). Neotropical Putranjivaceae. 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/Putranjivaceae.htm.