Polemoniaceae Juss.

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

Morphology

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).

Distribution

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.

Diagnostic

Other important characters

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

Distinguishing characters (always present)

• Calyx connate.
• Stamens adnate to the corolla.
• Style with three stigmatic branches.

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

General Description

General notes

• Some species of Cobaea, Cantua, and Polemonium, in particular Cobaeascandens 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.

Notes on delimitation

• The family has previously been placed in the Solanales close to Boraginaceae, Convolvulaceae, and Hydrophyllaceae by Cronquist. Recent evidence from molecular studies suggests, however, that Polemoniaceae is closer related to Ericaceae and Fouquieriaceae.

Number of genera

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

Status

• Native, primarily at higher elevation.

Literature

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.