Leaf anatomical study of five Macaranga species (Euphorbiaceae)

The anatomical variations in the leaves of Macaranga tanarius, M. javanica, M. gigantea, M. hulletii and M. hypoleuca were investigated so that they can be used as an additional tool for identification of the species. Characters such as the anticlinal wall pattern, types of stomata, vascular tissue pattern, shapes of the leaf margin, types of trichomes and types of leaf venation were identified. The adaxial and abaxial anticlinal walls are sinuous in M. hulletii, M. tanarius, M. javanica and M. gigantea but straight to wavy in M. hypoleuca. The paracytic stomata are present in all species except M. javanica which has the staurocytic type. All species except M. gigantea have open-type venation in the lamina and the incomplete-type at the margins. The closed vascular system and medullary vascular bundle were observed in all species. All five Macaranga species showed the presence of laticifer cells in their petiole and midrib. All have similar rounded-end shape leaf margin except for M. hypoleuca which has a fibrous cell at the end of the leaves. This unique characteristic will be useful in identification of that species. Simple unicellular trichomes were present in M. tanarius, M. hulletii, and M. gigantea, while glandular trichomes were found in M. hypoleuca and M. javanica. In M. javanica, the glandular trichomes were situated in crypts on the abaxial surface which can be a useful diagnostic character