Oreopolus Schltdl. includes one South American species of rather succulent, hemicryptophytic shrubs with well developed rootstocks. Oreopolus glacialis (Poepp. & Endl.) Ricardi is found in the southern Andes from central Chile and Argentina south to Tierra del Fuego. It can be recognized by its ternate leaves, its triangular stipules that are interpetiolar and fused to the petiole bases on each side, its flowers that are solitary or few in terminal and axillary clusters, its yellow salverform corollas with slender long tubes, and its papery loculicidal capsules. The flowers are diurnal and distylous. The tissues do contain raphides, although these may be difficult to observe.
Oreopolus has been confused with another genus of southern South America, Cruckshanksia Hook. & Arn. However these genera differ in several characters, as summarized in the key below. Oreopolus and its relationship to Cruckshanksia have been studied by Ricardi (1963) and Taylor (1996), and Oreopolus has been treated floristically recently by Moore (1983) and Bacigalupo (1999).
Oreopolus was previously included in the Hedyotideae by many authors, although Bremekamp and later Anderson & Rova (1999) placed it in the Cruckshanksieae. More recently, based on molecular data Bremer & Manen (2000) transferred both Oreopolus and Cruckshanksia to the neotropical tribe Coussareae. In their expanded circumscription Coussareae comprises a notable range of fruit types, from single- to multi-seeded, fleshy, indehiscent fruits (Coussarea, Coccocypselum) to leathery schizocarps (Declieuxia) and dry multi-seeded capsules (Heterophyllaea); it is not yet clear what morphological features unite the genera now placed in this tribe.
Author: C.M. Taylor.
The content of this web page was last revised 8 April 2008.