Neotropical Rapateaceae

Raquel Fernandes Monteiro

Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (JBRJ), Brazil.

Description

Herbs caespitose, perennial, often in swampy areas, frequently mucilaginous; rhizome short, erect or prostrate. Leaves distichous, spirodistichous or rosulate, often equitant, rarely petiolate (Rapatea longipes Spruce ex Körn., Saxo-fridericia aculeata Kornicke), sometimes with margin aculeate (Saxo-fridericia aculeata); leaf sheaths developed and invaginating; leaf blades ensiform, lanceolate or linear. Inflorescences compound, axillary or terminal, capituliform, usually involved by two or more spathes; spikelets few to many, pedicellate or sessile, comprising a single terminal flower surrounded by several sterile bracts; flower monocline, actinomorphic, or slightly zygomorphic, perianth in two differentiated whorls; sepals 3, rigid, papyraceous, or membranaceous, similar to bracts, hyaline at the base, free or connate; petals 3, white, yellow or red, sometimes with blotches, membranaceous, usually connate, with lobes lanceolate, ovate or obovate; stamens 6, adnate to the corolla tube, anthers basifixed, introrse, sometimes with terminal appendages, dehiscencing by 1, 2 or 4 apical or subapical pores or short slits; ovary superior, carpels 3, locules 3; ovules anatropous, 1-8 per locule, basal or axile placentation; stylus simple, erect; stigma capitate; loculicidal capsules. Seeds globose, oblong, striated or muricate, chalky endosperm.

Notes on delimitation

  • Rapateaceae is placed within the order Poales (APG III, 2010) as a Bromeliaceae sister group.  Mayacaceae is close to Rapateaceae in some studies because both have poricidal anthers.
  • Rapateaceae is organized in 5 tribes: Stegolepidieae, Schoenocephalieae, Saxofridericieae, Monotremaeae, Rapateeaea.

Distribution in the Neotropics

  • Rapateaceae is restricted to the Neotropics with the exception of Maschalocephalus dinklagei Gilg & Schumann that occurs in West Africa. The center of species diversity of Rapateaceae are the lowlands Guyana Shield and the Amazon.

Distinguishing characters (always present)

  • Mucilage cells, stomatal guard cells dumbell-shaped, uniseriate colleters, inflorescence capitate and scapose, anthers with pores or short slits, microsporogenesis simultaneous.

Number of genera

17 genera with 16 ocurring in the Neotropics ~100 spp.

  • Amphiphyllum Gleason (1 sp.)  - Brazil and Venezuela.
  • Cephalostemon Schomb.(5 spp.) - Brazil, Bolivia, Suriname and Venezuela.
  • Duckea Maguire. (4 spp.) - Brazil, Colombia  and Venezuela.
  • Epidryos Maguire. (3 spp.) - Brazil, Colombia, Equador, Guyana, Panamá  and Venezuela.
  • Guacamaya Maguire. (1 sp.) - Colombia and Venezuela.
  • Kunhardtia Maguire. (2 spp.) - Venezuela.
  • Marahuacaea Maguire. (1 sp.) - Venezuela.
  • Monotrema Koern. (5 spp.) - Brazil, Colombia and Venezuela.
  • Phelpsiella Maguire. (1 sp.) - Venezuela.
  • Potarophytum Sandw. (1 sp.) - Guyana.
  • Rapatea Aubl. (27 spp.) - Brazil, Bolivia, Colombia, Ecuador, Guyana, French Guyana, Peru, Suriname and Venezuela.
  • Saxofridericia Schomb.(7 spp.)  -  Brazil,  Colombia, French Guyana, Guyana, Suriname,  and Venezuela.
  • Schoenocephalium Seub. (4 spp.)  - Brazil, Colombia and Venezuela.
  • Spathanthus Desv. (2 spp.) Venezuela, Brazil, Colombia, Guyana and French Guyana.
  • Stegolepis Klotzsch ex Koern. (33 spp.) - Brazil, Guyana, Panamá and Venezuela.
  • Windsorina Gleason. (1 sp.) - Guyana.

Useful tips for generic identification

Status

  • All the family is native in Neotropics, except for the genus Maschalocephalus.

General notes

  • The species usually occurs in habitats with humid soil.

Important literature

Berry, P. 4004. Rapateaceae.  In: Berry, P.E., K. Yatskievych & B.K. Holst (eds.), Flora of the Venezuelan Guayana Vol. 8, pp. 413-472. Missouri Botanical Garden Press, St. Louis.

Dahlgren, R.M.T, Clifford, M.T. & Yeo, P.F. 1985. The families of monocotyledons: structure, evolution and taxonomy, pp. 391-395. Springer-Verlag, Berlin.

Givnish T.J., Millam K.C., Evans T.M., Hall J.C., Pires J.C., Berry P.E. & Sytsma K.J. 2004. Ancient vicariance or recent long-distance dispersal? Inferences about phylogeny and South American-African disjunctions in Rapateaceae and Bromeliaceae. International Journal of Plant Sciences 165: S35-S54.

Gleason, H.A. 1923. Windsorina, a New Genus of Rapateaceae. Bulletin of the Torrey Botanical Club 50(4): 147-152.

Maguire, B. 1958. Rapateaeae.  In: B. Maguire & J.J. Wurdack (eds.), The Botany of the Guayana Highland, part III. Mem. New York Bot. Gard. 10: 19-49.

Maguire, B. 1965. Rapateaceae. In B. Maguire & J.J. Wurdack (eds.), The Botany of the Guayana Highland, part VI. Mem. New York Bot. Gard. 12(3): 69-102.

Maguire, B. 1979. Additions to the Rapateaceae. Acta Amazonica 9: 267-269.

Maguire, B. 1982. Rapateaceae. In: Z. Luces de Febres & Steyermark, J.A. (eds.), Flora Venezuela 11, part II 11, pp. 85-203. Ediciones Funación Educación Ambiental, Caracas.

Seubert, M. 1847. Rapateaceae. In: Martius, C.F. Von & Urban, I. (eds.), Flora Brasiliensis. v. 3(1), pp. 125-132. Typographia regia, Munich.

Stevenson, D. W., Colella, M. & Boom, B.1998. Rapateaceae. In: K. Kubitzki, H. Huber, P.J. Rudall, P.S. Stevens & T. Stützel (eds.) The families and genera of vascular plants, Vol. 4, pp. 415-424. Springer-Verlag, Berlin.

How to cite

Monteiro, R.F. (2011). Neotropical Rapateaceae. In: Milliken, W., Klitgĺrd, 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/Rapateaceae.htm.