Pollens and seeds of Hypoestes and Rhinacanthus collected from different field localities in Taiz and Soqotra Island, Yemen were investigated by using light and scanning electron microscopes. Pollen grains of Hypoestes were prolate in equatorial view, lobate trigonal to lobate circular in polar view whereas those of Rhinacanthus were subspheroidal and rounded trigonal in polar view. The aperture was tricolporate and exine ornamentation was coarsely reticulate for all species in the two genera. Scanning electron microscopy and morphological observations showed that mature dry seeds of Hypoestes and Rhinacanthus have various sizes and shapes, the surface ornamentations observed were reticulate to cristate, an addition to the tuberculum and papillae. The three Hypoestes species differ in the seed structure which are useful for identification and their high structural diversity provides an important taxonomic value for species differentiation.
An anatomical study was carried out on 14 taxa belonging to Selaginellaceae in an attempt to study their stipe anatomical characteristics and to provide anatomical data for the selected taxa in Selaginellaceae. Out of 29 taxa of Selaginellaceae recorded in Peninsular Malaysia, 14 taxa have been selected namely Selaginella alutacia, S. argentea, S. frondosa, S. intermedia var. intermedia, S. intermedia var. dolichocentrus, S. mayeri, S. morganii, S. ornata, S. plana, S. polita, S. roxburghii var. roxburghii, S. stipulata, S. wallichii and S. willdenowii. Method used in this study was sectioning using sliding microtome. Findings in this study have shown that Selaginellaceae species studied can be clustered into two groups based on the stipe stellar systems, which are monostelic and tristelic groups. There are some variations exist in the cross sections of the stipes of the same species due to the presence and absence of the leaf trace. Each species is proved to have distinct stipe anatomical characteristics that can be used to differentiate species in Selaginellaceae.