RESUMODeterminação do número de cromossomos e análise do comportamento meiótico são excelentes contribuições aos estudos de relações taxonômicas e padrões evolutivos dentro de grupos de espécies vegetais. Espécies de leguminosas arbóreas da subfamília Caesalpinioideae, ocorrentes na Região Sul do Brasil, têm sido pouco analisadas do ponto de vista citotaxonômico. Este trabalho teve por objetivos determinar o número de cromossomos e analisar o comportamento meiótico de onze espécies arbóreas dessa subfamília. O número de cromossomos na maioria das espécies analisadas foi 2n = 28 cromossomos (x = 14). Foi encontrado 2n = 24 (x = 12) em Senna multijuga (L.C. Rich.) H. S. Irwin & Barneby e Schizolobium parahyba (Vell.) Blake, e 2n = 26 (x = 13) em Peltophorum dubium (Spreng.)Taub. Os núcleos apresentaram padrão arreticulado em todas as espécies e o comportamento meiótico foi regular em seis espécies estudadas. Sugere-se ampliação das coletas e análises citogenéticas em mais indivíduos e espécies de forma a gerar informações adicionais que permitam conclusões mais abrangentes sobre este grupo tão importante. Palavras-chave:Leguminosae; cromossomos; meiose. ABSTRACTChromosome counts and meiotic behaviour analysis are excellent contributions for studies on taxonomic relationships and evolutionary patterns in plants. The tree legume species of the subfamily Caesalpinioideae have been poorly analysed cytogenetically. This work aimed at determining the number of chromosomes and analysing the meiotic behaviour in 11 species of Caesalpinioideae. Basic chromosome numbers in most of the analysed species were 2n = 28 (x = 14). Senna multijuga (L. C. Rich.) H. S. Irwin & Barneby and Schizolobium parahyba (Vell.) Blake presented 2n = 24 (x = 12) and Peltophorum dubium (Spreng.) Taub. 2n = 26 (x = 13). In all the species nuclei presented an areticulate pattern and a regular meiosis in the six species studied. Further collections and cytogenetic analyses with a major number of individuals and species are suggested, in order to provide additional data for a more comprehensive study on this group of plants.

Chromosome numbers, karyotypes, meiotic behaviour and pollen analysis are presented for species of Chamaecrista Moench (Leguminosae, Caesalpinioideae, Cassieae ) native to southern Brazil: C. nictitans ssp. patellaria , C. nictitans ssp. disadena , C. repens , C. rotundifolia , C. flexuosa , C. vestita and C. desvauxii . Meiotic behaviour is reported for the first time for all the taxa and was very regular; only bivalents were formed at diakinesis and metaphase I, chromosome disjunction and segregation were regular at anaphases I and II, meiotic indexes were over 99% and pollen fertility was over 92%. Pollen grains were subprolate in C. flexuosa and C. vestita and prolatespheroidal in the other taxa. Karyotypes were symmetrical in all six species and the data are original, except for C. nictitans ssp. p atellaria. Chromosome number is presented for the first time for C. repens (2 n = 16) and has been confirmed for the other taxa: 2 n = 14 for C. desvauxii , 2 n = 32 for the tetraploid C. nictitans ssp. patellaria and C. nictitans ssp. disadena , and 2 n = 16 for the other species. These two basic numbers found in the genus, x = 7 and x = 8, point to chromosome evolution by dysploidy, which has also been accompanied by polyploidy.

-Chromosome numbers, meiotic behaviour, meiotic indexes and pollen fertility are reported for 17 Senna Mill. species occurring in Southern Brazil. Haploid numbers were n=11, 12, 13, 14 and 28. No intraspecific variability was detected; n=14 predominated. The only accession of S. rugosa showed to be tetraploid, in contrast to the a previous reference for this species. Meiotic behaviour was generally regular for all species and accessions, but some irregularities such as uni and multivalents and unequal segregation were occasionally observed. Meiotic indexes were high, over 95%. Mean pollen fertility was over 81% for all species, but in some taxa much lower values were found in some accessions. All species had prolate-spheroidal pollen grains. No relation between grain size, taxonomic position and chromosome number could be established. Our results, together with literature data, suggest that x=14 is the basic number for the genus, probably a secondary number derived from the x=7 suggested for all Caesalpinioideae, and that the other numbers in the genus represent a disploid series. A broader cytogenetic survey of a more representative number of species, along the geographic distribution of the genus, should be done addressing questions such as the extent of intra and inter-specific variability in chromosome number, occurrence of polyploidy and the real role of disploidy in Senna evolution

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A synopsis of the genus Galactia (Leguminosae) in Brazil, including taxonomy, ecology, economic potential, and conservation is presented. A taxonomic key, description of one new species (Galactia cordifolia), new synonyms, illustrations, a brief description of the main diagnostic characters of each species, and notes on distribution, ecology and uses are presented.