| Polylepis | |
|---|---|
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| Polylepis rugulosa | |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Rosales |
| Family: | Rosaceae |
| Subfamily: | Rosoideae |
| Tribe: | Sanguisorbeae |
| Subtribe: | Sanguisorbinae |
| Genus: | Polylepis Ruiz & Pav. |
| Species | |
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See text | |
Polylepis is a genus comprising 28 recognised shrub and tree species,[1] that are endemic to the mid- and high-elevation regions of the tropical Andes.[2] This group is unique in the rose family in that it is predominantly wind-pollinated. They are usually gnarled in shape, but in certain areas some trees are 15–20 m tall and have 2 m-thick trunks. The foliage is evergreen, with dense small leaves, and often having large amounts of dead twigs hanging down from the underside of the canopy. The name Polylepis is, in fact, derived from the Greek words poly (many) plus letis (layers), referring to the shredding, multi-layered bark that is common to all species of the genus.[2] The bark is thick and rough and densely layered for protection against low temperatures. Some species of Polylepis form woodlands growing well above normal tree line within grass and scrub associations at elevations over 5000 m; which makes Polylepis appear to be the highest naturally occurring arboraceous angiosperm genus in the world.[2]
- ^ Schmidt-Lebuhn, A.N.; Kessler, M.; Kumar, M. (2006). "Promiscuity in the Andes: Species relationships in Polylepis (Rosaaceae, Sanguisorbeae) based on AFLP and morphology". Systematic Botany. 31 (3): 547–559. doi:10.1600/036364406778388629.
- ^ a b c Simpson, Beryl B. (1979). "A revision of the genus Polylepis (Rosaceae: Sanguisorbeae)" (PDF). Smithsonian Contributions to Botany (43): 1–62. doi:10.5479/si.0081024x.43.