Butterfly pollination in the tropics is considered somewhat effective or solely effective in a few plant species. In the present study, we tested the hypothesis that Mandevilla tenuifolia (Apocynaceae), which has floral attributes associated with psychophily, has strategies adapted to pollination by butterflies, restricting other floral visitors and making these insects act as efficient pollinators. We analysed the floral and reproductive biology of M. tenuifolia, as well as the frequency and efficiency of its flower visitors. M. tenuifolia is an herb whose flowers have strong herkogamy and secondary pollen presentation on the style head, which corresponds to 60.4% of pollen on the anthers. Flower longevity and the long period of receptivity of the stigmatic region associated with the large amount of pollen removed in the first visits suggest that flowers remain functionally female during part of anthesis. Butterflies, mainly of the families Nymphalidae and Pieridae, are the only pollinators of M. tenuifolia. Despite being self-compatible, M. tenuifolia depends on biotic vectors for fruit production. A non-significant difference in fruit set between controlled treatments and natural conditions suggests that the pollinators are efficient. The inclination resulting from the landing of butterflies on flowers, together with flower morphology, guiding the insect proboscis inside the floral tube, as well as the frequency and efficiency of butterfly visits, are evidence of the close relationship between butterflies and M. tenuifolia, and also of the efficiency of these insects as pollinators.

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-(Reproductive phenology, floral biology and pollination of Allamanda blanchetii, an Apocynaceae endemic of the Caatinga). The reproductive phenology, floral biology, pollination mechanism and breeding system of Allamanda blanchetii A.DC. were studied in natural populations in the Almas Farm, Paraíba, Brazil. Allamanda blanchetii is a shrubby species, endemic of the Caatinga, flowering from February to July, with peak in March-April. The fruiting followed the flowering and continued until September. The tubular flowers are pink, their strong herkogamy preventing self pollination. The pollen grains are deposited in the upper side of the style head (non-receptive region), still in the pre anthesis phase (dehiscent anther), characterizing a secondary pollen presentation. The flowers produce an average of 36.6 µL of nectar, that is the only resource to the floral visitors. Allamanda blanchetii is self incompatible and the results suggest a late-acting self-incompatibility mechanism. The floral attributes are compatible with the melittophilous and psychophilous syndromes. In fact, the observed pollinators were the bee Eulaema nigrita Lepeletier, as main pollinator, and four species of butterflies, which act as secondary pollinators. The occurrence of strong herkogamy, secondary pollen presentation and self-incompatibility mechanism indicates high degree of specialization of pollination and breeding systems of A. blanchetii.Key words -herkogamy, secondary pollen presentation, self incompatibility RESUMO -(Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga). A fenologia reprodutiva, a biologia floral, o mecanismo de polinização e o sistema reprodutivo de Allamanda blanchetii A.DC. foram analisados em populações naturais na Fazenda Almas, Paraíba, Brasil. Allamanda blanchetii é uma espécie arbustiva, endêmica da Caatinga, com floração de fevereiro a julho e pico nos meses de março e abril. A frutificação acompanhou a floração e estendeu-se até o mês de setembro. As flores são tubulares e de coloração rosa, cuja forte hercogamia evita a autopolinização. O pólen é depositado na parte superior da cabeça do estilete (região não receptiva), ainda na fase de botão em pré antese (anteras deiscentes), caracterizando a apresentação secundária de pólen. As flores produzem uma média de 36,6 µL de néctar, o qual é o único recurso para os visitantes florais. Allamanda blanchetii é auto-incompatível e os resultados sugerem mecanismo de incompatibilidade de ação tardia. Seus atributos florais estão relacionados com as síndromes de melitofilia e psicofilia e, de fato, os polinizadores registrados foram a abelha Eulaema nigrita Lepeletier como principal polinizador e quatro espécies de borboletas que atuam como polinizadores secundários. A ocorrência de forte hercogamia, apresentação secundária de pólen e mecanismo de auto-incompatibilidade indicam o elevado grau de especialização dos sistemas de polinização e reprodução de A. blanchetii.Palavras-chave -apresentaçã...

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Dimorphandra gardneriana Tul. is a legume, the fruits of which are used in routine extraction by the pharmaceutical industry. The objective was to study the morphological aspects of seeds, germination, seedlings, and young plants of Dimorphandra gardneriana Tul. The study was conducted at the Laboratory of Seed Analysis (LAS), Center of Agricultural Sciences, Federal University of Paraíba (CCA-UFPB), Areia - PB. The external morphological characteristics observed of the seeds were color, texture, and consistency of the teguments; seed shape; hilum and micropyle position; color and thickness of raphe and other structures present; besides internal embryo characteristics (cotyledons, hypocotyl-radicle axis, plumule, and central cylinder); and presence of the endosperm. The seed imbibition curve was determined by the weight of the seeds over a period of 90 h, evaluated every 6 h, with germination being considered as the protrusion of the primary root, or the moment when the primary root breaks the integument, and normal seedlings were evaluated on the 5th day after sowing. Most of the morphological characteristics identified in the plants and seedlings of D. gardneriana resembled those observed for other species of the same genus. The seeds of D. gardneriana Tul., were medium sized, with an average length of 11.95 mm, width of 5.33 mm, and thickness of 4.3 mm, unitegmic with a hard tegument, and impermeable to water. The process of imbibition of the seeds was initially slow and the three-phase curve of imbibition was not clear. The germination was epigeic and phanerocotiledonar and began on the 5th day after sowing.