The generic position of Lithraea brasiliensis Marchand (Anacardiaceae): evidence from fruit and seed structure

In Lithraea brasiliensis Marchand the exocarp is characterized by brachysclereids and the parenchymatous mesocarp by large secretory ducts; inner sclerenchymatous ridges are absent in the mesocarp. The stratified endocarp s.s. comprises a crystal layer, palisade-like brachysclereids, osteosclereids and macrosclereids. The osteosclereids are characterized by a distinct light line or linea lucida, which has hitherto also Seen recorded in a species of Rhus. In the partially pachychalazal seed, a typical Anacardiaceae-like hypostase typifies the chalazal part of the seed coal, while the integumentary seed coat reveals a well preserved outer epidermis, a compressed endotegmen and well developed inner cuticular layer. Our comparison of the characters of the ovule, fruit and seed of L. brasiliensis with those of various species of Rhus and other genera of the tribe Rhoeae (some closely related) presents evidence that L. brasiliensis could be most closely associated with the genus Rhus. (C) 1998 The Linnean Society of London.