Comparative Leaf Blade Anatomy of Selected Philippine Melastomataceae

Transverse sections of  leaf blade of  seven species of  Melastomataceae, representing four genera, namely, Astronia, Dissochaeta, Medinilla, and Melastoma were analyzed. Similarities and differences among the species were observed in terms of the presence of adaxial hypodermis  as well as the number of cell layers in palisade and spongy mesophyll. Except for Dissochaeta acmura, all species exhibit a hypodermis occurring below the upper epidermis, and among the species having this specialized tissue, the number of cell layers varies. Sclerified palisade mesophyll was observed in Medinilla annulata, M. inaequifolia, and M. merrittii. These non-epiphytic  species of Medinilla differ from previously studied epiphytic Medinilla in having thinner hypodermis and abundant air spaces in the spongy mesophyll. Candelabra hairs were observed in D. acmura while shaggy hairs were observed in M. inaequifolia and Melastoma malabathricum. No hairs were found in the leaf blades of the other four species. These anatomical characters contribute to  the available baseline information needed for understanding diversity of Family Melastomataceae.

 

Keywords: Astronia, Dissochaeta,  Medinilla, Melastoma,  sclerified mesophyll, hypodermis, candelabra hairs