Aerial parts of endemic pichana were harvested in December 1996 at different localities of northern Patagonia. Origin: Planicie Banderita, Dept. Confluencia, Province of NeuquCn. Habitat: altitude, 327 m; average temperature in the station, 21.8 ℃; annual precipitation, 125 mm; sandy soils. Aerial parts (5 kg, 2 kg of dried material;humidity, 11%) from four well developed plants at the fullflowering stage (December, 1996). Sample 2 : Origin: RincBn de 10s; Sauces, Dept. of Pehuenclies, Province of Neuqukn. Habitat: altitude, 750 m; average temperature in the station, 20.9 ℃; annual precipitation, 147 mm; sandy and gritty salty soils. Aerial parts (5 kg, 1.85 kg of dried material, humidity, 10%), from two well developed plants at the full flowering stage, and after several days copious rains (December, 1996). Sample 3: Origin: Coronel GBmez, Dept. General Roca, Province of Rio Negro. Habitat: altitude, 242 m; average temperature in the station, 22.5 ℃; annual precipitation, 179 mm; sandy and stony soils. Aerial parts (4.5 kg, 1.3 kg of dried material, humidity, 9%), from 12 young plants at the beginning flowering stage (December, 1996).

Fifty-four components, representing approximately 84.6-97.4% of the oil samples, were identified. The samples consisted mainly of hydrocarbons and oxygenated monoterpenes. The major constituents were limonene (28.7-56.7%), 6R-7R-bisabolone (3.2-9.1%), sabinene (0.1-11.0%) and citronellal (2.4-5.2%). Significant differences among the content of the three samples could be the result of changes in the climatic conditions (sample 2: Rincon de los Sauces, Province of Neuquen, after strong rains) or by translocations in different parts of the plant (sample 3: Coronel Gomez, Province of Rio Negro, more leaves and less stems).