Monographs Details: Stifftia
Authority: Carlquist, Sherwin. 1957. Anatomy of Guayana Mutisieae. Mem. New York Bot. Gard. 9 (3): 441-476.
Family:Asteraceae
Scientific Name:Stifftia
Discussion:The genus Stifftia, although not found on the Guayana Highland, shows some degree of relationship to the above genera and may be considered in this connection. The pollen grains of Stifftia chrysantha (fig. 91 A, B) have a remarkable feature not previously reported for Mutisieae. Evenly arranged on the surface of these grains are eleven areas of thickened exine, three on each intercolpar face and one at each pole. These thickenings are the result of greater development of the outer ektexine (fig. 91 B). Numerous wide but very short spines or emergences occur on the thickened areas of the exine as well as on the unthickened areas. However, no such thickened areas are found on the pollen of Stifftia uniflora, the grains being evenly spinulose. The pollen grains of S. uniflora, not illustrated here, would match closely the drawings of Chimantaea rupicola in figure 93 A, B. In shape, the pollen grains of these two species of Stifftia are dissimilar, since S. chrysantha has large, subprolate grains, while those of S. uniflora are smaller and prolate sphaeroidal. Excepting the thickened areas in S. chrysantha, the exine thickness of these two species is very similar; likewise both have long, narrow furrows.