**3. Some geographical features of the Chilean territory**

Details of the geographical and evolutionary characteristics of the Chilean flora have been published elsewhere (Arroyo et al., 1993; Grau, 1995, Squeo et al., 2008; Stuessy & Taylor, 1995). Chile stretches from north to south for nearly 4270 km (ca. 39 degrees) along the western coast of South America, between 17°30'S (10 km North of Visviri) and 56°30´S (Diego Ramírez islands) and extends to the Antarctica at the South Pole (Chilean Antarctic Territory). Also belong to Chile the oceanic islands San Félix and San Ambrosio (Desventuradas islands), the archipelago of Juan Fernández and the Polynesian islands Easter Island and Sala and Gómez. Including the Chilean Antarctic Territory, the country's length spans for about 73 degrees. The maximum width occurs in southern Chile (52º21'S), where there is over 400 km between the Pacific Ocean and the Andes, but the overall width of the country usually does not exceed 200 km. Chile borders with Peru on the North, on the East with Argentina and Bolivia, on the West with the Pacific Ocean and on the South with the South Pole. In the north, Chile shares with Bolivia, Peru and Argentina the Altiplano, a plateau which does not descend from 4000 m of altitude. The Andes runs end-to-end the territory, establishing the border with Argentina. The Andes reaches heights of almost 7000 m in the northern zone, while to the south it falls below 2500 m. The Atacama Desert, considered to be one of the driest places in the world, dominates the climate on the north (Pankhurst & Hervé, 2007), with rainfall below 10 mm per year. From the Aconcagua valley to the region of Bío-Bío (approx. 32-38°S), the Mediterranean climate is dominant, with the exception of the high peaks of the Andes with cold weather due to the altitude. The Mediterranean region of Chile is included in the Chilean hotspot of biodiversity (Winter Rainfall Area of Central-Northern Chile Hotspot or Chilean Winter Rainfall and Valdivian Forests). The Chilean hotspot is located between 25 and 40°S (Arroyo et al., 1999), including the regions of Coquimbo and Atacama and extending to the region of Los Lagos in southern Chile. This hotspot contains 3892 vascular plant species, of which 1957 (more than 50%), are endemic to Chile. The Chilean hotspot covers almost 400.000 km2 including the islands San Félix, San Ambrosio and the archipelago of Juan Fernández (Conservation International, 2011). South of 38°S the mixed deciduous-evergreen temperate forests occur.

The biogeographic sketch of the Chilean vegetation (Cabrera & Willink, 1973) divided the territory into two phytogeographical regions (*Región Neotropical* and *Región Antárctica*) and domains (*Dominio Patagónico* and *Dominio Subantárctico*). A detailed account of the Chilean

perennial usually with solid culms. Leaves distichous with adaxial membranous ligule, sometimes a fringe of hairs or absent. Inflorescences panicle, racemes or compound inflorescences. Spikelets 2-flowered, with the lower floret staminate or barren, single or paired, dorsally compressed, with two glumes, disarticulating below the glumes (rarely above the glumes). Lodicules 2, fleshy. Caryopsis with short hilum, hard endosperm containing simple (rarely compound) starch grains; embryo large, epiblast absent, scutellar cleft present, mesocotyl internode elongated, embryonic leaf margins overlapping. Stomata with triangular or dome-shaped subsidiary cells; bicellular microhairs of the panicoid type present. Photosynthetic pathway C3, C4 and C3/C4 intermediates (GPWG, 2001). The presence of bifloral spikelets with the lower flower staminate or neuter, simple starch grains and molecular data, both from chloroplast and nuclear DNA, are synapomorphies that

Details of the geographical and evolutionary characteristics of the Chilean flora have been published elsewhere (Arroyo et al., 1993; Grau, 1995, Squeo et al., 2008; Stuessy & Taylor, 1995). Chile stretches from north to south for nearly 4270 km (ca. 39 degrees) along the western coast of South America, between 17°30'S (10 km North of Visviri) and 56°30´S (Diego Ramírez islands) and extends to the Antarctica at the South Pole (Chilean Antarctic Territory). Also belong to Chile the oceanic islands San Félix and San Ambrosio (Desventuradas islands), the archipelago of Juan Fernández and the Polynesian islands Easter Island and Sala and Gómez. Including the Chilean Antarctic Territory, the country's length spans for about 73 degrees. The maximum width occurs in southern Chile (52º21'S), where there is over 400 km between the Pacific Ocean and the Andes, but the overall width of the country usually does not exceed 200 km. Chile borders with Peru on the North, on the East with Argentina and Bolivia, on the West with the Pacific Ocean and on the South with the South Pole. In the north, Chile shares with Bolivia, Peru and Argentina the Altiplano, a plateau which does not descend from 4000 m of altitude. The Andes runs end-to-end the territory, establishing the border with Argentina. The Andes reaches heights of almost 7000 m in the northern zone, while to the south it falls below 2500 m. The Atacama Desert, considered to be one of the driest places in the world, dominates the climate on the north (Pankhurst & Hervé, 2007), with rainfall below 10 mm per year. From the Aconcagua valley to the region of Bío-Bío (approx. 32-38°S), the Mediterranean climate is dominant, with the exception of the high peaks of the Andes with cold weather due to the altitude. The Mediterranean region of Chile is included in the Chilean hotspot of biodiversity (Winter Rainfall Area of Central-Northern Chile Hotspot or Chilean Winter Rainfall and Valdivian Forests). The Chilean hotspot is located between 25 and 40°S (Arroyo et al., 1999), including the regions of Coquimbo and Atacama and extending to the region of Los Lagos in southern Chile. This hotspot contains 3892 vascular plant species, of which 1957 (more than 50%), are endemic to Chile. The Chilean hotspot covers almost 400.000 km2 including the islands San Félix, San Ambrosio and the archipelago of Juan Fernández (Conservation International,

support the monophyly of the Panicoideae (Aliscioni et al., 2003).

**3. Some geographical features of the Chilean territory** 

2011). South of 38°S the mixed deciduous-evergreen temperate forests occur.

The biogeographic sketch of the Chilean vegetation (Cabrera & Willink, 1973) divided the territory into two phytogeographical regions (*Región Neotropical* and *Región Antárctica*) and domains (*Dominio Patagónico* and *Dominio Subantárctico*). A detailed account of the Chilean vegetation can be found in (Gajardo, 1994). To the Patagonian domain belong the Provinces *Provincia Altoandina*, *Provincia Puneña*, *Provincia del Desierto*, *Provincia Chilena Central* and *Provincia Patagónica* (Cabrera & Willink, 1973). *Provincia Altoandina* extends from Venezuela to Tierra del Fuego, in the high Andes. In the Andes of Mendoza (Argentina) and adjacent regions of Chile of *Provincia Altoandina* dominate communities of *Festuca*, *Poa*, *Deyeuxia* and *Nasella*. *Provincia Puneña* extends from 15-27°S, in the high Andes between 3200 and 4000 m of altitude. Communities of *Pappostipa chrysophylla* (coirón amargo) are common in this area. *Provincia del Desierto* is located on the Pacific coast between 5 and 30°S. This province has a warm, dry weather because of the Humboldt Current. The coastal fogs known as "*camanchacas*" allow the growth of vegetation mainly with species of the family Nolanaceae (*Alona*, *Nolana*). This province (also known as *Subregión del desierto costero*) is very interesting from a floristic point of view due to the high number of endemic species that live there (Gajardo, 1994). South of La Serena (Region of Coquimbo), the coastal fogs provide sufficient moisture to sustain the forest of Fray Jorge, a relict forest of *Aextoxicon punctatum* (olivillo, Aextoxicaceae), which only reappears only in southern Chile (Valdivia). *Provincia Chilena Central* extends between 32ºS and 38°S (except in the high mountains), including the regions of Valparaíso, Metropolitana, O'Higgins, Maule and Bío-Bío. This province is dominated by sclerophyllous forests with *Bielschmiedia miersii* (belloto, Lauraceae), *Peumus boldus* (boldo, Monimiaceae), *Cryptocarya alba* (peumo, Lauraceae), *Kageneckia oblonga* (huayu, Rosaceae), *Lithrea caustica* (litre, Anacardiaceae), *Quillaja saponaria* (quillay, Rosaceae), *Colliguaya dombeyana* (colliguay, Euphorbiaceae), etc. In the central valley known as Depresión Intermedia, the espinal of *Acacia caven* (espino, Mimosaceae) is the dominant vegetation community. The espinal has a very high diversity of Poaceae. Species commonly found in the prairie of the espinal are *Agrostis capillaris*, *Aira caryophyllea*, *Aristida pallens*, *Avena barbata*, *Briza maxima*, *B. minor*, *Bromus hordeaceus*, *B. rigidus*, *B. stamineus*, *Chascolytrum subaristatum*, *Chusquea quila*, *Cynosurus echinatus*, *Dactylis glomerata*, *Danthonia chilensis* var. *aureofulva*, *Hordeum chilense*, *H. murinum*, *Lolium multiflorum*, *L. perenne*, *Melica violacea*, *Nasella gibba*, *N. neesiana*, *N. pfisteri*, *Paspalum dasypleurum*, *Phalaris amethystina*, *Poa annua*, *Piptochaetium montevidense*, and *Vulpia bromoides*. In southern Chile, *Provincia Patagónica* comprises the regions of Aysén and Magallanes. This region is characterized by dry and cold climate with vegetation consisting mainly of grassland steppe (Fig. 1), where communities of *Festuca pallescens* and *F. gracillima* are important in Aysén and Magallanes, respectively (Luebert & Pliscoff, 2006). Other species frequently found are *Festuca argentina*, *Jarava neaei*, *Deschampsia antarctica, D. elongata* (Pisano, 1985).

*Región Antárctica* and *Dominio Subantárctico* include two provinces: *Provincia Subantárctica* and *Provincia de Juan Fernández*. The archipelago of Juan Fernández, situated 670 km west of continental Chile in the Pacific Ocean, comprises three islands of volcanic origin: Masafuera or Alejandro Selkirk (33°37'S, 80°46'W), Masatierra or Robinson Crusoe (33°37'S, 78°50'W), and Santa Clara. Masafuera is located 180 km west of Masatierra whereas the small island Santa Clara is located 1 km SW of Masatierra (Errázuriz et al., 1998; Swenson et al. 1997). The archipelago of Juan Fernández is characterized by a high level of endemism; 31% of the vascular plants are endemic (Baeza et al., 2007; Swenson et al. 1997). The vascular flora of the islands comprises 42 families of flowering plants, including the monotypic and endemic Lactoridaceae. According to Skottsberg, the largest families are Asteraceae, Cyperaceae and Poaceae (Skottsberg, 1956). On the other hand, the high number of alien plants is a serious threat to the native flora of Juan Fernández (Matthei et al., 1993; Swenson et al., 1997).

Systematic Diversity of the Family Poaceae (Gramineae) in Chile 79

regions in which the country is divided (Table 1), we calculated the collection index (Squeo

*Mean number of estimated taxa\** 

17°30'-19°06' AP 109.0 150.5 72.4 41.5 429 0,23 18°56'-21°39' TA 73.0 120.0 60.9 47.0 250 0,34 20°56'-26°05' AN 125.0 181.0 69.1 56.0 853 0,11 25°17'-29°11' AT 106.0 173.8 61.0 67.8 385 0,20 29°02'-32°16' CO 167.0 237.8 70.2 70.8 888 0,16 32°02'-33°57' VA 186.0 253.6 73.3 67.6 1055 0,16 32°55'-34°19' ME 198.0 260.6 76.0 62.6 1375 0,13 33°51'-35°01' OH 89.0 161.7 55.0 72.7 172 0,49 34°41'-36°33' MA 172.0 261.6 65.8 89.6 648 0,25 36°00'-38°30' BB 263.0 337.0 78.0 74.0 3118 0,07 37°35'-39°37' AR 188.0 244.2 77.0 56.2 1254 0,14 39°16'-40°07' LR 143.0 185.5 77.1 42.5 742 0,18 40°07'-44°04' LL 131.0 202.3 64.8 71.3 634 0,19 43°38'-49°16' AY 112.0 179.6 62.4 67.6 373 0,26 48°39'-62°22' MG 158.0 195.3 80.9 37.3 1829 0,07

Table 1. Poaceae diversity of Chile at national and regional level. NCO = number of collected specimens, CI = collection index, Regions: AP = Arica and Parinacota, TA = Tarapacá, AN = Antofagasta, AT = Atacama, CO = Coquimbo, VA = Valparaíso, ME = Metropolitan, OH = O'Higgins, MA = Maule, BB = Bío-Bío, AR = Araucanía, LR = Los Ríos, LL = Los Lagos, AY = Aysén, MG = Magallanes and Antarctica Chilena. \*Mean value of ICE,

The collection index takes values ranging from 1 to near zero. Value 1 indicates poor collection effort while values near to 0 indicate that the region is over-collected (Squeo et al., 1998). Collections are not uniformly distributed along the country; on the contrary, some regions have been collected more or less intensely (e.g. Bío-Bío, Metropolitan, Magallanes, Araucanía, Valparaíso), while others regions (e.g. O'Higgins, Tarapacá and Aysén) have been weakly collected (Table 1, Fig. 5). The species accumulation curves allow the estimation of species richness from a sample and to compare the species richness of different areas. The accumulation curve for the country together with the curves of the five species richness estimators are shown in Fig. 3. The accumulation curve for the all country tends to be asymptotic (Fig. 3) and the mean number of estimated taxa (Table 1) indicated that our database included about 85.5% of the taxa expected to be found in Chile. There are about 70 taxa not yet collected, nevertheless, these indicators show that the overall knowledge of

Chao2, Jacknife1, Jacknife2, Bootstrap and Michaelis-Menten estimators.

*Number of observed taxa* 

CI = Number of species/Number of collections (1)

*Represented percentage* 

*Estimated number of unknown taxa* 

*NCO CI* 

et al., 1998):

*Lat °S Region* 
