The Clusiaceae family includes about 38 genera and 1100 species, mainly found in tropical regions. Calophyllum brasiliense Cambess. is commonly known as guanandi in Portuguese and its leaves and bark are employed in folk medicine as anti-inflammatory, to treat rheumatism and to improve vascular tone. Pharmacological essays have demonstrated antibacterial and analgesic activities. Since there is insufficient data on this species, this work has dealt with the anatomy of the leaf and stem of C. brasiliense, aiming to expand the knowledge on this alleged medicinal plant.

The botanical material was collected in the Floresta do Palmito, on the outskirts of Paranaguá-PR, from previously identified specimens. Adult leaves and stem fragments, obtained 10cm from the apex, were fixed in FAA70, free-hand sectioned and stained with astra blue and basic fuchsine. For ultra-structure analysis, the fixed material was dehydrated, covered with gold and examined in a scanning electron microscope.

In the leaf, the epidermal cells are sinuous and show evident primary pits, in surface view. The cuticle is thick and smooth, and anomocytic stomata are exclusively seen on the abaxial side (hypostomatic leaf). A sub-epidermal layer of parenchymatic cells occurs next to the adaxial surface and the mesophyll is dorsiventral, comprehending about two rows of palisade parenchyma and a multiseriate spongy parenchyma. The midrib is plain-convex and traversed by a collateral vascular bundle arranged in V-shape, which is encircled by an incomplete sclerenchymatic sheath. The stem has circular cross-section and shows uniseriate epidermis and cortex with moderately thick-walled parenchymatic cells. The vascular cambia produce phloem outwards and xylem inwards. Calcium oxalate crystals and secretory structures are seen in the leaf and stem.

The anatomical description of C. brasiliense agrees with the Clusiaceae family. These aspects, evaluated altogether, are useful for identifying the species and for pharmacognostic purposes.