is here summarized, eleven years after the publication of the original treatment. A summary of all Lycophyta, Monilophyta, Gimnospermae, and Angiospermae (Monocotyledoneae and Dictotyledoneae), updated to July 2019, is here presented. This checklist includes nowadays 289 families, 2813 genera, and 18931 species. The number of species is 1238 higher than that registered for the original version, which shows the large number of floristic and taxonomic news published for the area, and the importance of keeping this information updated. Tables sumarizing the floristic information for the Southern Cone and for each country are included, distinguishing by higher groups, families and genera; a comparison with the original version of the catalogue is conducted; endemic families and genera are specified, as well as the introduced ones; finally floristic relationships between the involved countries are evaluated. In addition, two digital appendixes are included, one with the new version of the catalogue, the other with a summary of the flora for each country.

Widely understood as a condensed raceme, the Asteraceae capitulum is the evolutionary result of a very reduced, condensed thyrsoid. Starting from that point, evolution worked separately only on the racemose developmental control/pattern within Asteraceae and mainly on the cymose developmental control/pattern within Calyceraceae, producing head-like inflorescences in both groups but with very different diversification potential. We also discuss possible remnants of the ancestral cephalioid structure in some Asteraceae.

Spikelet structure and grouping are key characters to identify grasses. Here we tested the possibility that spikelet pairs, a distinctive morphological structure of many Andropogoneae and Paniceae, are the starting point for a secondary single spikelet condition that can also explain the change of spikelet orientation among Paniceae genera. As a first approach, we studied the inflorescence development of Paspalum simplex, P. stellatum, and Axonopus sufultus to clarify the origin of the spikelet orientation and other basic homologies. The results support that solitary spikelets of A. suffultus are homologous to the subsessile spikelets of P. simplex and that solitary spikelets of P. stellatum are homologous to the pedicellate spikelet of P. simplex. This last homology supports that spikelet orientation results from a differential reduction/abortion of either the pedicellate or the subsessile spikelet primordia. We also discuss the possibility that the RAMOSA and polar auxin pathways could play a role in the abortion of the lateral subsessile spikelets in P. stellatum. However, the apical meristem inhibition observed in A. suffultus and P. stellatum seems to depend on a very different genetic control, suggesting that the single spikelet condition is homoplasic within Paniceae and derived from at least two different genetic mechanisms.

We present an inventory of the vascular plants of the Misiones province, with a total of 3418 taxa, which accounts for more than 30% of the plants of Argentina. A total of 47 endemic taxa from Misiones province were analyzed and categorized following IUCN standards. We recognized 761 exclusive species for the province of Misiones within Argentina and species without records in recent times. Finally, a total of 16 native and introduced taxa are cited for the first time for Argentina.