Neotropical Polemoniaceae

Bente B. Klitgård

Royal Botanic Gardens, Kew, UK.  

Description

Herbs, sometimes shrubs (Huthia Brand) or lianas (Cobaea Cav.); if herbs then usually perennial, rarely annual; stems and leaves glandular and viscid, often with a strong odour. Leaves usually alternate, rarely opposite (Loeselia L.), usually simple or pinnate (Cobaea) with the terminal leaflet modified into a branched tendril; leaf margin entire to lobed or serrate to spinulose (Loeselia); stipules absent. Inflorescences axillary or terminal, cymose, in racemose, paniculate or capitate clusters, or flowers rarely solitary (Cobaea). Flowers 5-merous, usually actinomorphic, rarely zygomorphic (some Loeselia species), hermaphroditic; calyx connate; corolla connate; stamens 5, adnate to the corolla; ovary inserted on a nectariferous disc, carpels 3, syncarpous, with 3 locules, ovules 1-many per locule. Fruit a dehiscent, dry usually 3-locular capsule; seeds 1-many, often mucilaginous when wet, the surface smooth to angled, sometimes with a conspicuous marginal wing (Cantua Juss. ex Lam., Cobaea and Huthia).

Notes on delimitation

Distribution in the Neotropics

Worldwide Polemoniaceae comprise about 18-20 genera and 350-380 species. Of these seven genera and 40-59 species occur in tropical America:

  • Bonplandia Cav. (1 species) - woodlands and forests of Mexico.
  • Cantua (5-20 species) - interandean Ecuador, Peru and Bolivia.
  • Cobaea (20 species) - forests of tropical Central and NW South America.
  • Gilia Ruiz & Pav. (1 species) - shrublands, woodlands and forests of W North America.
  • Huthia (2 species) - interandean Ecuador, Peru, and Bolivia.
  • Loeselia (10-14 species) - shrublands and forests of S North America, Central America and NW South America.
  • Polemonium L. (1 species) - North America.

Distinguishing characters (always present)

Other important characters

  • Nectariferous disc present.
  • Seeds with a conspicuous marginal wing.

Number of genera

  • Seven genera and 40 species occur in tropical America.  See above for a list of all genera present.

Useful tips for generic identification

  • Cantua: shrubs or small trees often with dimorphic leaves; inflorescence terminal 3-10-flowered, raceme-like or somewhat capitulate; seeds with marginal wing.
  • Cobaea: vines with pinnately compound leaves ending in a tendril; inflorescence cymose, 1-5-flowered; corolla broadly campanulate; seeds with a marginal wing.
  • Loeselia: annuals, woody-based perennial herbs or subshrubs; leaf margins often aristate; calyx usually actinomorphic, leaf-like, hyaline or membranous; corolla usually actinomorphic or zygomorphic; seeds angled or winged.

    Notable genera and distinguishing features


    Status

    • Native, primarily at higher elevation.

    General notes

    • Some species of Cobaea, Cantua, and Polemonium, in particular Cobaea scandens Cav. (cup or saucer vine), are widely cultivated throughout the world as ornamentals, and a tea made from the leaves of Cobaea scandens serves as a cough medicine in Mexico and Central America. Cantua buxifolia Lam. is the national flower of Peru and was first cultivated by the Incas as a decorative plant around their temples.

    Important literature

    Grant, V. 1998. Primary classification and phylogeny of the Polemoniaceae, with comments on molecular cladistics. American Journal of Botany 85(6): 741-752.

    Johnson, L.J., Schultz, J.L., Soltis, D.E. & Soltis, P.S. 1996. Monophyly and generic relationships of Polemoniaceae based on matK sequences. American Journal of Botany 83 (9): 1207-1224.

    Johnson, L.J., Soltis, D.E. & Soltis, P.S. 1999. Phylogenetic relationships of Polemoniaceae inferred from 18S ribosomal DNA sequences. Plant Systematics & Evolution 214: 65-89.

    Maas, P. J. M. & Westra, L. Y. Th. 2005. Neotropical Plant Families. 3rd ed. Pp. 246. A.R.G. Gantner Verlag K.G., Ruggell.

    Porter, J.M. 1997. Phylogeny of Polemoniaceae based on nuclear ribosomal internal transcribed spacer DNA sequences. Aliso 15(1): 57-77.

    Porter, J.M. & Johnson, L.A. 1998. Phylogenetic relationships of Polemoniaceae: inferences from mitochondril NAD1B intron sequences. Aliso 17(2): 157-188.

    Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008.

    Wilken, D.H. 2004. Polemoniaceae. Pp. 300-312. In: Kubitzki, K. (ed.). The families and genera of vascular plants VI. Springer-Verlag, Berlin, Heidelberg, New York.

    Wilken, D.H. 2004. Polemoniaceae. Pp. 304-306. In: Smith, N., Mori, S. A., Henderson, A., Stevenson, D. W. and Heald, S. V. (eds.). Flowering Plants of the Neotropics. The New York Botanical Garden, Princeton University Press, Princeton.

    How to cite

    Klitgård, B.B. (2009). Neotropical Polemoniaceae. 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/Polemoniaceae.htm.