Two new species from central Brazil of the South American genus Oryctina (L
oranthaceae) are described and illustrated, O. eubrachioides Kuijt and O. q
uadrangularis Kuijt. The absence of a calyculus in the male flower of sever
al Oryctina species represents a nearly unique feature within the family, a
nd the lack of staminodia in the female flower has elsewhere been noted onl
y in two species of Cladocolea. The affinities of Brazilian species with Ve
nezuelan ones are briefly discussed. Distinctions between the two groups of
species, based largely on the structure of bracteoles and staminodia, sugg
est that the generic name Maracanthus may have to be revived for the Venezu
elan species. A new key to the genus is presented, including the new specie
s.