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On the Flora of the Guayana Highland
Vol. 2, No. 2 (Dec., 1970), pp. 85-100
Published by: Association for Tropical Biology and Conservation
Stable URL: http://www.jstor.org/stable/2989766
Page Count: 16
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The Guayana Highland is a great upland characterized by the spectacularly eroded Roraima sandstones, associated sediments, and intrusive elements which overlay the ancient immutable basic crystalline Guayana Shield, which with the larger Brazilian Shield to the south gives form and permanence to the continent of South America. The Roraima sediments are usually considered to be Cretaceous in origin. It is suggested, on botanical evidence, that the emergence of these sediments may antedate the Cretaceous, and that the original flora, which developed thereupon and persists into this age, was a part of the early evolution and development of the contemporary angiosperm flora. Persisting autochthonous elements are prominent. A preliminary review indicates that the historical relationships of the provincial flora of Guayana lie, in order, with those of: 1) the Brazilian Highland; 2) tropical Africa: 3) the Andes; 4) the Caribbean, and 5) Malaysia. The magnitude of these relationships requires the early existence of historical land continua. The floras of the surrounding Amazon and Orinoco Basins, the Hvlea, are youthful.
Biotropica © 1970 Association for Tropical Biology and Conservation