Levantamento e características ecológicas de orchidacea e da mata ciliar do rio dourados, Dourados-MS

The Orchidaceae is one of the largest flowering plants family and with a great importance to conservation. However, no survey on orchid flowers can be found in Mato Grosso do Sul. Thus, the objective of this work was to make a survey of the Orchidaceae species and of its ecology features in a riparian forest in a fragment of Floresta Estacional Semi-Decidual that belongs to the riparian forest of the Dourados River. The inventory was made by using a sweeping method for collection, and in addition to this the vertical and horizontal position of epiphytes were assessed on the hosts. For characterization of microclimate, it was used a thermohygrometer and luximeter. It was identified 17 species of 13 genera. Of the listed genera, the most abundant ones were: Acianthera, Macradenia and Capanemia. It was also noted a vertical and horizontal distribution of the Orchidaceae in relation to inverse gradient of water and light availability. Some species tended to be sensitive to height level categorization, whereas others seemed to occur with similar frequency along the host. In relation to the cardinal orientation, the apparent preferential response for south and east directions was associated to the low sampling effort and lower water availability, which could occur because the north face is opposed to the water body.

As Apocynaceae s. str. da região de Bauru, São Paulo, Brasil

The present study describes a survey of the Apocynaceae in different types of vegetation, in the region of Bauru, in the Center-West of São Paulo State. Of the 25 species encountered, distributed into 15 genera, representation ranges as follows: Forsteronia G. Mey, five species; Aspidosperma Mart., four species; Mandevilla Lindl., three species; Prestonia R. Br., two species; and Condylocarpon Desf., Hancornia Gomez, Himatanthus Willd. ex Roem. et Schult., Macrosiphonia Müll. Arg., Mesechites Müll. Arg., Odontadenia Benth, Peltastes Woodson, Rhodocalyx Müll Arg., Secondatia A. DC., Tabernaemontana L. and Temnadenia Miers, one species each. In addition to both distribution data, and flowering and fruiting times, identifications keys, descriptions and illustrations of the species are presented.

Flora arbustivo-arbórea do fragmento de floresta estacional semidecidual do Ribeirão Cachoeira, município de Campinas, SP

An inventory of the woody flora (trees and shrubs), was carried out in the Ribeirão Cachoeria forest (233.7ha, 650m high, 46°55'58''W, 22°50'13''S), the second largest and best conserved fragment of semideciduous tropical forest in the municipality of Campinas, São Paulo state, Southeastern Brazil. The soil is a red-yellow podsol and the climate is of Köppen's Cwag type. Collections were made from August/1996 to September/1997. Only fertile individuals with a perimeter at breast height of 9cm or greater were included in the survey. One hyndred and seventhy five species were identified, belonging to 119 genera and 49 families. The most important families were Myrtaceae (14 species), Rutaceae and Fabaceae (13), Caesalpiniaceae (11), Solanaceae (9), and Rubiaceae (8). Some species were found for the first time in the region: Tachigali multijuga Benth. and Schoepfia brasiliensis A.DC. The flowering peak for most species was from August to October. Maximum fruit production was from August to November. Most species are zoochoric (58%), but 23% were anemochoric and 19% autochoric. The floristic composition of this forest and another 20 forests from São Paulo state were compared. The results obtained indicate the existence of distinct groups of forests. The most homogeneus group contains forests from the municipality of Campinas with similarity of 40%. This suggests that these forests are possibly fragments of a original continuous forest in the Campinas region.

Abundância de ramos reprodutivos e produção de sementes em populações de Ipomoea pes-caprae (L.) R. Br. na Ilha de Santa Catarina, Brasil

The variation in the proportion of reproductive branches, fruit, and seed production of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) were evaluated at ten beaches on Santa Catarina Island, state of Santa Catarina, Brazil. Three patches per beach of Ipomoea pes-caprae were monitored, involving two reproductive cycles. Ipomoea pes-caprae presented initially an average length of patches of 14 m, with 9.6 branches/m² and 39% of reproductive branches. The proportion of reproductive branches varied between the cycles, but there was not noticed an alternation of reproductive effort between the subsequent cycles. There was a reduction in the percentage of reproductive branches at six localities. In four beaches where Ipomoea pes-caprae populations declined, occurred reduction in the reproductive vigor, and in the seed production, being these declines associated to strong sea erosion. In another hand, in one beach with population increase, there were little reproductive branches due to the occurrence of young stolons. Four patches never maturated fruits, being three of these located at small beaches. The fruit and seed productions in the patches showed values up to 40 fruits/m² and up to 140 seeds/m², respectively. Populations with great seed production were localized in areas adjacent to great coastal plains, which may represent potential seed sources for areas with small seed production in the island.

Florivory and sex ratio in Annona dioica St. Hil. (Annonaceae) in the Pantanal at Nhecolândia, southwestern Brazil

Annona dioica St. Hil. is a species that grows to approximately 2 m tall and is very widespread in the cerrados. Individual plants of this androdioecious species produce numerous hermaphroditic or male flowers, but few fruits. The aim of this study was to determine the sex ratio among the plants and to compare the frequency of herbivory between male and hermaphroditic flowers. The fieldwork was done by studying flowering plants in grasslands used as pasture for cattle at Fazenda Nhumirim. One hundred and forty-seven male plants and 71 hermaphroditic plants were examined and produced a total of 194 and 94 flowers, respectively, during the study period. The male:hermaphrodite sex ratio was 2.07:1, and was similar to the male:hermaphrodite flower ratio of 2.06:1. The frequency of florivory rate in hermaphrodites was significantly higher than in male flowers (33.0%, n = 31, and 25.7%, n = 50, respectively; G = 14.83; d.f. = 1; p < 0.001). The mean fresh weights of male and hermaphroditic flowers were significantly different (8.38 ± 2.40 g vs. 6.93 ± 2.68 g, respectively; 0 ± SEM; n = 50 each; t = 2.479; d.f. = 49; p = 0.017). These results indicate that the low fruit set in this species can be explained by the sex ratio, the greater herbivory of hermaphroditic flowers and the probable absence of pollinators.

Taxonomia do gênero Euploca Nutt. (Heliotropiaceae) no Brasil

This work deals with a taxonomic study of the genus Euploca (Heliotropiaceae) in Brazil; seventeen species are recorded. A keyfor identification, descriptions, illustrations and comments, besides distribution, habitat, flowering and fruiting data for the species are presented.