The Sous region (also spelt Sus, Suss, Souss or Sousse) (, ) is a historical, cultural and geographical region of Morocco, which constitutes part of the region administration of Souss-Massa and Guelmim-Oued Noun. The region is known for the endemic argan tree (which has become a symbol of Souss) as well as for being the capital of the Shilha Berber ethnic group. It is a major commercial and tourist agricultural region of Morocco. Vegetable production, shared between very large farms and small producers, contributes to the economic development of the region. The Souss plain produces 40% of Moroccan citrus fruits, and 60% of the production of early vegetables. Sus al-Aqsa consisted of the southern/western part, and Sus al-Adna consisted of the northern/eastern part; however, there were never any precise boundaries between the two. There was also a ribat at Massa near the Atlantic coast.