Anatomical characters of stem segments in species of Opuntioideae (Cactaceae) subfamily

ABSTRACT

This work presents a general anatomical characterization of the stem segments of four species of Opuntioideae with emphasis on the dermal and ground tissue systems, and a review of the anatomical studies for the subfamily. Some characters are distinctive for the studied species, such as: stomata position in the same level of the remaining epidermal cells, occurrence of papillose epidermis and trichomes, stomata type, cell type of the palisade cortex, and occurrence of mucilaginous channel next to the phloem. In conclusion, our results show that some anatomical aspects on the dermal and ground systems are useful in the diagnosis of species. Furthermore, original data about distribution of medullary cells with secondary wall thickening are described in Opuntia or Opuntioideae.

Keywords:
papillose epidermis; wide-band tracheids