Neotropical Strelitziaceae

Jon L.R. Every

Royal Botanic Gardens, Kew, UK. 

Description

Perennial, massive (up to 12m), acaulescent or suckering herbs with short and massive sympodial rhizomes, developed as runners (Phenakospermum Endl.) or with corm -like aerial shoots (Strelitzia Aiton), semi-woody when mature. Leaves alternate, distichous, in fan-like structures at top of trunk, eligulate, simple, petiole long or absent, blade large, entire (though sometimes torn due to wind damage), glabrous, midrib thick, venation pinnate with parallel-arching, lateral veins fusing to form a margin. Inflorescence terminal or lateral, indeterminate, scapiflorous, erect, giant thyrse, made up of many monochasial cymes (cincinni) each subtended by a spathaceous, persistent, tough, cymbiform (boat-shaped), green-yellowish, mucilage-filled bract. Flowers bisexual, zygomorphic, large (up to 28cm), tepals 6 in 2 whorls, outer 3 distinct, subequal in shape, inner 3 basally +/- connate, the 2 anterior/abaxial, connate (free at base), sagittate, larger than the posterior/adaxial hooded 1 and enclosing filaments and style (in Strelitzia), subtended by ridged, persistent bracteoles, becoming papery in fruit; stamens 5(-6), filaments adnate to perianth tube, thecae 2 per anther, anthers basifixed; ovary inferior, carpels 3, 3-loculate, style 1, filiform, lax, stigma 1, conical-cylindrical, ovules 4 to many in each locule, septal nectaries present, deeply sunken. Fruits loculicidal, woody, green capsules, dehiscing by 3 valves. Seed numerous, black, shiny, arillate, red (Phenakospermum) to orange (Strelitzia) or blue, fringed with fibrous, threadlike trichomes, lobed or not, abundant starchy endosperm.

Notes on delimitation

  • Often treated as part of the Musaceae.
  • Morphological and molecular data suggest that the Strelitziaceae are sister to the non-Neotropical family Lowiaceae in a clade with the Musaceae and Heliconiaceae (Kress et al. 2001).
  • In the pantropical order Zingiberales as part of the bananas alongside the gingers i.e. Cannaceae, Costaceae, Marantaceae and Zingiberaceae (APG 2, 2003).

Distribution in the Neotropics

  • Throughout the Neotropics.
  • Along river margins, in swamp forests, forest edges, and disturbed areas.
  • 50-700m.

Distinguishing characters (always present)

  • Large, entire leaves.
  • Thick midrib with parallel-arching lateral veins which fuse to form a margin.
  • Massive, scapiflorous inflorescence, nearly 4m long in Phenakospermum.
  • Sturdy boat-shaped, spathaceous, green bracts.
  • Distinctive zygomorphic, bisexual flowers.
  • Woody capsular fruit.
  • Arillate seed with distinctively red or orange  thread-like trichomes.

Key differences from similar families

Number of genera

  • Strictly, one Neotropical genus Phenakospermum with one species P. guyannense (Rich.) Endl. ex Miq., but treated here to include both the bird of paradise plant Strelitzia reginae Aiton and the traveller's palm Ravenala madagascariensis Sonn., both of which are introduced into the Neotropics.

Useful tips for generic identification

Phenakospermum:

  • Found in the Neotropics east of the Andes and particularly abundant in forests bordering seasonally flooded savannas.
  • Terminal inflorescence.
  • 5 stamens.
  • Red to orange aril.

Strelitzia:

  • Posterior inner tepal/petal enclosing the filaments and style in a central grove.
  • Orange aril.

Ravenala Adans.:

Status

  • Phenakospermum endemic to tropical South America.
  • Strelitzia reginae Banks ex Aiton cultivated and naturalized in the Neotropics.
  • Ravenala madagascariensis (traveler's palm), introduced from Madagascar, is commonly cultivated.

General notes

  • Pollinated by bats (Phenakospermum) and birds (Strelitzia).
  • Flowers of Phenakospermum stay receptive for only one night (Kress & Stone, 1993).
  • Seeds of Phenakospermum cooked and eaten by some indigenous people.

Important literature

Andersson, L. 1998. Strelitziaceae. In: K. Kubitizki (ed.). The Families and Genera of Vascular Plants vol. 4, pp. 451-55. Springer-Verlag, New York.

Andersson, L. 2005. Strelitziaceae. In: Steyermark, J. A., Berry, P. E., Yatskievych, K. & Holst, B. K. (eds). Flora of the Venezuelan Guayana. Vol. 9, pp 281-283. Missouri Botanical Garden Press, St. Louis.

APG 2. 2003. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society 141: 399-436.

Dahlgren, R. M. T., Clifford & H. T., Yeo, P. F. 1985. The Families of the Monocotyledons: Structure, Evolution and Taxonomy, pp. 358-9. Springer-Verlag, Berlin.

Kress, W. 1990. The phylogeny and classification of the Zingiberales. Annals of the Missouri Botanical Garden 77(4): 698-721.

Kress, W. J. & Stone, D. E. 1993. Morphology and floral biology of Phenakospermum (Strelitziaceae), an arborescent herb of the Neotropics. Biotropica 25: 290-300.

Kress, W.J., Prince, L.M., Hahn, W.J. & Zimmer, E.A. 2001. Unravelling the evolutionary radiation of the families of the Zingiberales using morphological and molecular evidence. Systematic Biology 50(6): 926-944.

Maas, P.J.M. & Westra, L.Y.Th. 2005. Strelitziaceae. Neotropical Plant Families. 3rd ed., p. 101. A.R.G. Gantner Verlag K.G., Ruggell.

Seeberg, O. 2007. Strelitziaceae. In: Heywood, V.H., R.K. Brummitt, A. Culham & O. Seberg (eds). Flowering plant families of the world, pp.402-403. Royal Botanic Gardens, Kew.

Stevens, P. F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/.

Stevenson, D. W. & Stevenson, J. W. 2004. Strelitziaceae. In: Smith, N., Mori, S. A., Henderson, A., Stevenson, D. W. & Heald, S. V. (eds). Flowering Plants of the Neotropics. pp. 482-3. The New York Botanical Garden, Princeton University Press, Princeton.

Watson, L. and Dallwitz, M. J. (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000.

How to cite

Every, J.L.R. (2009). Neotropical Strelitziaceae. 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/Strelitziaceae.htm.