Ìrúgbìn igi óákù je nut of the oaks and their close relatives (genera Quercus and Lithocarpus, in the family Fagaceae). It usually contains a single seed (rarely two seeds), enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad. Acorns take between about 6 and 24 months (depending on the species) to mature; see List of Quercus species for details of oak classification, in which acorn morphology and phenology are important factors.

Fallen acorns
Diagram of the anatomy of an acorn: A.) Cupule B.) Pericarp (fruit wall) C.) Seed coat (testa) D.) Cotyledons (2) E.) Plumule F.) Radicle G.) Remains of style. Together D., E., and F. make up the embryo.
àtúnṣe
  • Nupa Acorn Soup (Miwokan recipe)
  • Cooking With Acorns: A Major North American Indian Food
  • Krautwurst, Terry (1988). "A Fall Field Guide Nuts". Mother Earth News. Retrieved 20 October 2009.  Unknown parameter |month= ignored (help)
  • Julia F. Parker and Beverly R. Ortiz, It Will Live Forever: Traditional Yosemite Indian Acorn Preparation, Heyday Books, 2nd revised edition (1 September 1996), trade paperback, 160 pages, Àdàkọ:ISBN-10, Àdàkọ:ISBN-13
  • Proceedings of the symposium on the ecology, management, and utilization of California oaks, 26–28 June] USDA Forest Service General Technical Report PSW-044, Berkeley, California, 1980, edited by Timothy R. Plumb, 368 pages

    The symposium, held at Scripps College in Southern California, addressed most aspects of California's vast oak resource. Papers represented four major subject categories: ecological relationships, silviculture and management, damage factors, and products. Both scientific and applied information was presented, including original material not published previously. Individual topics ranged from taxonomy and historical relationships to management of insects and diseases. and various oak products. In California. oaks' value for wildlife, recreation, watershed protection, and esthetics exceeds their value for traditional lumber and wood products.