A. Alexandre, J. D. Meunier, A. M. Lezine, A. Vincens, and D. Schwartz, Phytoliths: indicators of grassland dynamics during the late Holocene in intertropical Africa, Palaeogeogr., Palaeoclimatol., Palaeoecol, vol.136, pp.213-229, 1997.
URL : https://hal.archives-ouvertes.fr/hal-01909698

J. W. Bartolome, S. E. Klukkert, and S. E. Parry, Opal phytoliths as evidence for displacement of native Californian grassland, Madrono, vol.33, issue.3, pp.217-222, 1986.

R. Bonnefille, A reassessment of the Plio-Pleistocene pollen records of East Africa, Paleoclimate and Evolution, with Emphasis on Human Origins, pp.299-310, 1995.

R. Bonnefille, A. Vincent, and G. Buchet, Palynology, stratigraphy and palaeoenvironment of a Pliocene hominid site, p.9, 1987.

, My) at Hadar, Ethiopia. Palaeogeogr., Palaeoclimatol., Palaeoecol, vol.60, pp.249-281

R. Bonnefille, G. Buchet, I. Friis, E. Kelbessa, and M. U. Mohamed, Modern pollen rain on an altitudinal range of forests and woodlands in South West Ethiopia, Opera Bot, vol.121, pp.71-84, 1993.

S. R. Bozarth, Classification of opal phytoliths formed in selected Dicotyledons native to the Great Plains, Phytolith Systematics, pp.193-214, 1992.

D. A. Brown, Prospects and limits of a phytolith key for grasses in the central United States, J. Archaeol. Sci, vol.11, pp.345-368, 1984.

W. V. Brown, The Kranz syndrome and its subtypes in grass systematics, Mem. Torrey Bot. Club, vol.23, pp.1-97, 1977.

J. S. Clark, Particle motion and the theory of charcoal analysis: source area, transport, deposition, and sampling, Quat. Res, vol.30, pp.67-80, 1988.

L. M. Delliquadri, A contribution to the climate of Ethiopia (including the Somalilands), vol.151, p.pp, 1958.

L. Diester-haas, H. J. Schrader, and J. Thiede, Sedimentological and paleoclimatological investigations of two pelagic ooze cores off Cape Barbas, Forschungs-Ergeb. Reihe C, vol.16, pp.19-66, 1973.

R. P. Ellis, A procedure for standardizing comparative leaf anatomy in the Poaceae. II; The epidermis as seen in surface view, Bothalia, vol.12, issue.4, pp.641-671, 1979.

F. A. , Report on survey of Awash River basin, United Nations, vol.1, p.pp, 1965.

R. F. Fisher, C. Newell-bourn, and W. F. Fisher, Opal phytoliths as an indicator of the floristics of prehistoric grasslands, Geoderma, vol.68, pp.243-255, 1995.

G. G. Fredlund and L. L. Tieszen, Modern phytolith assemblages from the North American Great Plains, J. Biogeogr, vol.21, pp.321-335, 1994.

G. G. Fredlund and L. L. Tieszen, Phytolith and carbon isotope evidence for late Quaternary vegetation and climate change in the southern Black Hills, South Dakota, Quat. Res, vol.47, pp.206-217, 1997.

G. G. Fredlund, W. C. Johnson, and W. Dort, A preliminary analysis of opal phytoliths from the Eustis Ash Pit, Frontier County, Nebraska. Inst. Tertiary-Quaternary Stud.-Inst. TER-QUA Stud. Symp. Ser, vol.1, pp.147-162, 1985.

I. Friis, The forest vegetation of Ethiopia, Acta Univ. Symb. Bot. Upssala, vol.26, issue.2, pp.31-47, 1986.

J. W. Geis, Biogenic silica in selected species of deciduous angiosperms, Soil Sci, vol.116, issue.2, pp.113-119, 1973.

J. B. Gillett, The plant formation of Western British Somaliland and the Harar Province of Abyssinia, Kew Bull, vol.1941, issue.2, pp.37-199, 1941.

H. B. Gilliland, The vegetation of Eastern British Somaliland, J. Ecol, vol.40, issue.1, pp.91-124, 1952.

J. B. Jones and E. R. Segnit, Water in the sphere-type opal, Mineral. Mag, vol.37, pp.357-361, 1969.

E. F. Kelly, Methods for extracting opal phytoliths from soil and plant material, Intern. Rep., Dep. Agron, vol.10, p.pp, 1990.

M. H. Kurman, An opal phytolith and palynomorph study of extant and fossil soils in Kansas (USA), Palaeogeogr., Palaeoclimatol., Palaeoecol, vol.49, pp.217-235, 1985.

D. Barboni, Palaeogeography, Palaeoclimatology, Palaeoecology, vol.152, pp.87-100, 1999.

J. Laroche, La silice et les plantes supérieures, Rev. Cytol. Biol. Vég, vol.40, pp.15-45, 1976.

L. Cohu and M. , Examen au Microscope Electronique a ` Balayage des cônes de silice chez les Cypéracées, C. R. Acad. Sci. Paris, vol.277, pp.1301-1303, 1973.

D. A. Livingstone and W. D. Clayton, An altitudinal cline in tropical African grass floras and its paleoecological significance, Quat. Res, vol.13, pp.392-402, 1980.

J. C. Menaut, The vegetation of African savannas, Tropical Savannas, vol.13, 1983.

C. R. Metcalfe, Anatomy of the Monocotyledons. I. Gramineae, 1960.

S. C. Mulholland, Plant Opal Phytolith Analysis in Archaeology and Paleoecology, Proc. 1984 Phytolith Research Workshop, pp.41-52, 1986.

S. C. Mulholland, Phytolith shape frequencies in North Dakota grasses: a comparison to general patterns, J. Archaeol. Sci, vol.16, pp.489-511, 1989.

S. C. Mulholland and G. Rapp, A morphological classification of grass silica-bodies, Phytolith Systematics. Emerg. Iss. Adv. Archaeol. Mus. Sci, vol.1, pp.65-89, 1992.

A. L. Ollendorf, Archeological implications of a phytolith study at Tel Miqne (Ekron), Israel. J. Field Archaeol, vol.14, pp.453-463, 1987.

A. L. Ollendorf, S. C. Mulholland, and G. Rapp, Phytolith analysis as a means of plant identification: Arundo donax and Phragmites communis, Ann. Bot, vol.61, pp.209-214, 1988.

P. G. Palmer and S. Gerbeth-jones, A scanning electron microscope survey of the epidermis of East African grasses, IV. Smithson. Contrib. Bot, vol.62, p.pp, 1986.

P. G. Palmer and A. E. Tucker, A scanning electron microscope survey of the epidermis of East African grasses, I. Smithson. Contrib. Bot, vol.49, p.pp, 1981.

P. G. Palmer and A. E. Tucker, A scanning electron microscope survey of the epidermis of East African grasses, II. Smithson. Contrib. Bot, vol.53, p.pp, 1983.

P. G. Palmer, S. Gerbeth-jones, and S. Hutchinson, A scanning electron microscope survey of the epidermis of East African grasses, III. Smithson. Contrib. Bot, vol.55, p.pp, 1985.

D. R. Piperno, Phytolith Analysis. An Archaeological and Geological Perspective, vol.280, p.pp, 1988.

I. Rovner, Potential of opal phytoliths for use in paleoecological reconstruction, Quat. Res, vol.1, pp.343-359, 1971.

G. Scurfield, C. A. Anderson, and E. R. Segnit, Silica in woody stems, Aust. J. Bot, vol.22, pp.211-229, 1974.

P. Sermolli, Una carta geobotanica dell, Africa Orientale, issue.1, pp.15-132, 1957.

B. N. Smith and W. V. Brown, The Kranz syndrome in the Gramineae as indicated by carbon isotopic ratios, Am. J. Bot, vol.60, pp.505-513, 1973.

L. L. Tieszen, M. M. Senyimba, S. K. Imbamba, and J. H. Troughton, The distribution of C3 and C4 grasses and carbon isotope discrimination along an altitudinal and moisture gradient in Kenya, Oecologia, vol.37, pp.337-350, 1979.

P. C. Twiss, Opal phytoliths as indicators of C3 and C4 grasses, Geol. Soc. Am. Abstr, vol.12, p.17, 1980.

P. C. Twiss, Dust deposition and opal phytoliths in the Great Plains, Trans. Nebr. Acad. Sci, vol.11, pp.73-82, 1983.

P. C. Twiss, Grass-opal phytoliths as climatic indicators of the Great Plains Pleistocene, Kans. Geol. Surv. Guidebook Ser, vol.5, pp.179-188, 1987.

P. C. Twiss, Predicted world distribution of C3 and C4 grass phytoliths, Phytolith Systematics. Emerg. Iss. Adv. Archaeol. Mus. Sci, vol.1, pp.113-128, 1992.

P. C. Twiss, E. Suess, and R. M. Smith, Morphology classification of grass phytoliths, Proc. Soil Sci. Soc. Am, vol.33, pp.109-115, 1969.

L. Watson, H. T. Clifford, and M. J. Dallwitz, The classification of Poaceae: subfamilies and supertribes, Aust. J. Bot, vol.33, pp.433-484, 1985.

B. J. Welle, On the occurrence of the silica grains in the secondary xylem of the Chrysobalanaceae, Iawa Bull, vol.1976, issue.2, pp.19-29, 1976.

F. White, The vegetation of Africa. A descriptive memoir to accompany the Unesco=AETFAT=UNSO vegetation map of Africa, Nat. Resour. Res, vol.20, p.356, 1983.

T. White, G. Suwa, and B. Asfaw, Australopithecus ramidus, a new species of early hominid from Aramis, Ethiopia, Nature, vol.371, pp.306-312, 1994.