Abstract

In Bromelioideae, the so-called nidularioid complex contains closely related genera, the circumscription of which has been problematic. The goal of this study was to describe the ovary and ovule anatomy of six species of the nidularioid complex belonging to Canistropsis, Canistrum, Edmundoa, Neoregelia, Nidularium and Wittrockia and to use these characters in a parsimony analysis of relationships. In all analysed species, schizogenous-type aerenchyma is present in the ovarian mesophyll. Edmundoa lindenii has trichomes on the ovary surface, and this character appears to be an autapomorphy for the species. Canistrum aurantiacum exhibited some autapomorphies, such as four cell layers in the outer integument, non-elongated cells in the nucellar epidermis and three or four layers of cells in the parietal tissue. In the remaining species of the complex, the presence of transversally orientated ovules and anticlinally elongated cells in the outer integument in the micropylar region appear to be synapomorphies. Canistrum aurantiacum shares few characters with the other species; these results and the latest phylogenetic analysis show that Canistrum spp. do not belong to the current nidularioid clade.

The genus Rhynchospora Vahl. (Cyperaceae) has about 270 species, two subgenera and 27 sections. Cytogenetic studies showed that polyploidy is the main mechanism of numeric changes in the karyotypes of Rhynchospora. However, some species have exhibited some evidence of agmatoploidy and symploidy. The occurrence of holocentric chromosomes seems to support more the events of fusion (symploidy) and fission (agmatoploidy), leading to the appearance and maintenance of intra-and interspecific variations based in disploidy. In this study, chromosome counts and recounts were performed in 14 species obtained from different Brazilian localities. New chromosome numbers have been reported for R. tenuis, R. globosa, R. pubera, R. nervosa, R. junciformis and R. asperula. The analysis showed the absence of primary constrictions on the chromosomes and numeric variation from 2n = 4 to 2n = 58. The primary (x = 5) and secondary (x = 6 and 9) basic numbers were again confirmed. Our results expand the information related to chromosome rearrangements in Rhynchospora and reinforce the role of polyploidy and dysploidy in karyotype differentiation in representatives of Cyperaceae.

No abstract

Tillandsioideae are composed of nine genera, most of these with unclear delimitation. The morphoanatomy of ovules and ovaries of 83 species from seven different genera was studied under light or scanning electron microscopy to contribute to the understanding of the relationships in the group. The nucellar epidermis and the parietal tissue showed a regular pattern for all Tillandsioideae. The presence of chalazal appendages, however, and their shape and size varied between the genera analysed. Most species had a single acuminate chalazal appendage. Catopsis was the only genus with multiple appendages. Guzmania and Racinaea lacked this structure. The integuments also presented a variable length and thickness among the different genera. The four to six layers of the outer integument were unique in Catopsis and the three cell layers condition in the inner integument of Tillandsia should be a retained feature as it was also observed in Catopsis. Many characteristics in ovule morphology presented here have great systematic value for distinguishing genera of the Tillandsioideae. In addition, these features can also help in the understanding of ovule evolution in Bromeliaceae as a whole.