**6. Conclusions**

90 The Dynamical Processes of Biodiversity – Case Studies of Evolution and Spatial Distribution

altitude (Matthei, 1973). Chloris comprises three species; all introduced (*C. gayana*, *C. radiata* and *C. virgata*). *Chloris gayana* is native from Africa (Senegal); in Chile it is found only in Easter Island (Anderson, 1974; Matthei, 1995). The other two species grow in Northern Chile. *Cynodon nitidus* is endemic to Chile. *Cynodon dactylon* is a common weed in ruderal places, both in continental Chile and Easter Island. *Eleusine indica* is found only in Easter Island. *Eleusine tristachya* is a common weed of gardens as well as orchards and meadows in Central Chile. Genus *Eragrostis* comprises 12 species, eight of them native and four

> AP TA AN AT CO VA ME OH MA BB AR LR LL AY MG **Political Regions of Chile**

Fig. 6. Number of Endemic, introduced, and native non-endemic species in the fifteen

*Eragrostis pycnantha, E. peruviana, E. weberbaueri, E. nigricans,* and *E. kuschelii* are restricted to Northern Chile. *Eragrostis peruviana* and *E. kuschelii* grow in Islas Desventuradas (approx. 26°S). *Eragrostis atrovirens* and *E. tenuifolia*, introduced from Eurasia, grow in Easter Island. *Eragrostis polytricha* grows in Central Chile. Spartina densiflora (austral cordgrass), a species probably native from the east coast of South-America (Bortolus, 2006), has been reported as an invasive species in North America, Europe and Africa (Ayres et al., 2004); it grows in

Endemic Introduced Native

introduced.

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00

political regions of Chile.

Fig. 7. *Chusquea culeou* in Aysén, Chile (A. Solís).

**Percentage of species**

The family Poaceae is represented in Chile by 523 species in 122 genera and eight subfamilies. Fifty eight species from 23 genera are endemic. *Megalachne* and *Gymnachne* are endemic to Chile. Endemic species represent about 11% of the Chilean grass flora. More than 20% are introduced species. Our data, based mostly on the collections of the two most important Chilean herbaria (CONC, SGO), indicate that the present knowledge of the Chilean Poaceae is good enough. The observed species richness reaches over 88% of the estimated species richness. However, the collection index calculated for the different political regions indicates a weak collection effort in some regions (e.g. O'Higgins, Tarapacá and Aysén). New expeditions to these regions are necessary to complete the inventory, because the knowledge of the species richness depends directly on its representation in the herbaria collections.
