Pericarp structure of Orania palindan (Blanco) Merr. in connection with the problem of determining the fruit morphogenetic type

Abstract

The genus Orania Zipp. forms the monotypic clade Oranieae of the subfamily Arecoideae and includes 30 species. Representatives of the genus are pleonant single-stemmed palms of small and large size with pinnate leaves without crownshaft. With the aim to determine the morphogenetic types of fruits of the genus Orania, the features of the development and structure of the mature pericarp, we studied the fruits of Orania palindan (Blanco) Merr. at 2 development stages. The pericarp of the studied species is divided into 3 histogenetic zones: single-layer exocarp and endocarp, and multilayer mesocarp. In the mA1 zone of the mesocarp, a sclereid belt was found that performs a structural function, and in the mA2 zone, a belt of mechanical elements that performs the function of protecting the seed, due to the endocarp is not lignified and is not able to provide effective protection of the seed. According to the totality of characters, the fruits of O. palindan are most similar to the fruits of Socratea hecatonandra (Dugand) R. Bernal from the tribe Iriarteeae. Conducted research showed that the fruits of the studied species histogenetically belong to berry of Nuphar-type, and functionally to pyrenarium of Latania-type.