Contributions to the anatomy of Sararanga (Pandanaceae)

Preliminary study shows the two species of Sararanga to differ considerably in morphology and anatomy. The presence of stellate trichomes in S. philippinensis is a major character separating the two species; such trichomes are not found elsewhere in the family. Massive strands of thickened cells (buttresses) extend across the leaf of S. sinuosu but appear absent from S. philippinensis. The leaf anatomy of the latter more closely resembles that common in Freycinetia. The photosynthetic tissue is not clearly differentiated into distinct layers. Both species of Sararanga have unspecialized stomata. The presence of raphides in different structures in the two species may be distinctive. The pollen grains are ellipsoidal, with an intricate reticulate exine. The fruits contrast in structure with those of Pandanus and Freycinetia and the seeds of Sararanga philippinensis have a characteristic elaborate testa.