Neotropical Proteaceae

Ghillean T. Prance

Royal Botanic Gardens, Kew, UK. 

Description

Trees or shrubs. Leaves alternate, opposite or whorled, simple, pinnatifid, pinnate or bipinnate usually coriaceous, exstipulate. Inflorescence simple or compound, axillary or terminal, racemose or paniculate. Flowers usually actinomorphic, bisexual, solitary or paired in axils of bracts, rarely ebracteate. Perianth of 4 valvate, free or variously united tepals; each with a slightly expanded limb. Stamens 4, usually all fertile, opposite the tepals; filaments partly or wholly adnate to tepals, rarely free. Hypogynous glands usually present, 4, scale-like or fleshy, free or fused. Gynoecium of 1 carpel. Ovary superior, rarely perigynous, sessile or stipitate, 1-locular; ovules 1-many, variously inserted; style simple often persistent, often with the apex expanded as a pollen presenter; stigma small, terminal or subterminal. Fruit dehiscent or indehiscent, a woody or coriaceous follicle, drupe or an achene. Seeds 1 to many, usually endospermic.

Notes on delimitation

  • Variously placed in earlier systems and often in Rosidae near to Elaeagnaceae. Others placed the family near to the Santalales, but usually considered basal.
  • The Angiosperm Phylogeny Group place the family in a basal order Proteales where it is close to Platanaceae and Nelumbonaceae, both of which differ considerably morphologically, but many genes support this grouping.

Distribution in the Neotropics

  • A largely southern hemisphere family consisting of 79 genera and ca. 1,700 species with Australia and southern Africa as its centers of greatest diversity.
  • Eight genera and 84 species occur in the Americas distributed from Mexico to Chile and Argentina of which five occur in the tropical region.
  • In the Americas the greatest diversity is in the Andes and eastern Brazil.

Distinguishing characters (always present)

  • Secondary pollen presentation.
  • 4-merous flowers.
  • Perianth uniseriate of tepals.
  • Swollen petiole bases common.
  • Winged seeds common in all genera except Panopsis Salisb.

Number of genera

Five Neotropical genera:

  • Euplassa Salisb.
  • Oreocallis R.Br.
  • Orites R.Br.
  • Panopsis Salis.
  • Roupala Aubl.

Useful tips for generic identification

Key to genera of Neotropical Proteaceae

1. Adult leaves pinnate... 2
1. Adult leaves entire, simple or pinnatifid, never pinnate... 3

2. Fruit a follicle, seeds winged; style erect... Roupala
2. Fruit indehiscent, seeds not winged; style curved ... Euplassa

3. Fruit indehiscent with thick hard or fleshy pericarp, seeds not winged... Panopsis
3. Fruit a dehiscent follicle, the pericarp thin not fleshy, seeds winged... 4

4. Hypogynous glands 4; ovules 2; flowers actinomorphic or only weakly diagnonally zygomorphic... 5
4. Hypogynous glands 3 lobed, broad, truncate; ovules many; flowers zygomorphic... Oreocallis

5. Ovules ascending; young inflorescences conical due to overlapping bracts subtending flower pairs; seed lateral to wing ... Orites
5. Ovules pendulous; young inflorescences not conical; bracts subtending flower-pairs small; seed central to wing ... Roupala

Status

  • All five genera are native and four are endemic to the Neotropics; Orites also occurs in Australia.

General notes

  • The leaves are often extremely variable and in species of Roupala are compound when young and simple when mature in some species, others may be consistently simple or compound.

Important literature

Plana, V. & Prance, G.T. 2004. A synopsis of the South American genus Euplassa (Proteaceae). Kew Bull. 59:27-45.

Prance, G.T. & Plana, V. 1998. The American Proteaceae.  Australian Systematic Botany 11: 287-299.

Prance, G.T., Edwards, K.S., Plana, V. & Pennington, R.T. 2008. Proteaceae. Flora Neotropica Monograph 100, 250 pages.

Sleumer, H. 1954. Proteaceae americanae. Bot. Jahrb. Syst. 76(2): 139-211.

How to cite

Prance, G.T. (2009). Neotropical Proteaceae. 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/Proteaceae.htm.