"Graminaceous" stomata were observed in Virola (Myristicaceae). Comments are made on the widespread occurrence of this type of stomata as well as the need for additional structural information which can show a variation gradient between the characteristic stomata type of the Graminae and Cyperaceae and the "graminaceous" stomata of dicotyledons.

Resumo Para complementar o trabalho de Anderson et al. (trabalho anterior) sobre a vegetação da campina, foram investigados três aspectos ecológicos adicionais, os quais não constavam na programação dos trabalhos de tese dos alunos do mestrado do INPA. No primeiro estudo, analisadas 50 ilhas pequenas que ocorrem na campina aberta (1). com um total de 25 espécies de plantas lenhosas e algumas plantas herbáceas, relacionando-se o tamanho das ilhas, a ocorrência das espécies e as associações entre as mesmas. No segundo, verificada a ocorrência de duas espécies de Loranthaceae, hemiparasitas, que ocorrem na campina aberta e sombreada (1), com tendência a terem hospedeiros específicos. Phthirusa rufa (Mart.) Eichl. (Loranthaceae) tem como hospedeiro Ouratea spruceana Engl. (Ochnaceae) e Phthirusa micrantha Eichl. (Loranthaceae) tende, entre outras espécies, a parasitar Hirtella racemosa Lam. var. racemosa (Chrysobalanaceae). Aspectos anatômicos e ecofisiológicos foram relacionados. No último trabalho ecológico foi analisada a ocorrência de algumas epífitas em cinco espécies de árvores na campina (aberta e sombreada) e na campinarana.

Summary We investigated three ecological aspects of the vegetation of an Amazonian campina The subjects studied were chosen to complement the study of Anderson et alii (1975) and the thesis studies of students of INPA. The first part is an analysis of the small islands of vegetation which occur in the open campina. We found a total of 25 species of woody plants and we also studied some herbaceous species. Data is presented on the occurrence of species and the associations between them and their correlation with island size. The second part is a study of two species of Loranthaceae (Phthirusa rufa (Mart.) Eichl. and P. micrantha Eichl). These hemi-parasites occur in the open and shady areas of the campina and show a tendency to have specific nosts, especially Hirtella racemosa Lam. var racemosa (Chrysobalanaceae) in the case of P. micrantha, and Ouratea spruceana Engl. (Ochnaceae) in the case of P. rufa. Some anatomical and ecophysiological aspects of this host-parasite relationship are also discussed. The final part is an analysis of the occurrence of some selected species of epiphytes in five species of trees which are common in the campina. The study was made in both sun and shade campina, and also in campinarana.

Resumo Estudo das Rhizophoraceas da Amazônia abrangendo 5 gêneros: Rhizophora, Cassipourea, Sterigmapetalum, Polygonanthus e Anisophyllea. Doze espécies dos referidos gêneros são estudadas e descritas. Novos taxa não foram encontrados, porém, diversos nomes foram colocados em sinonímia. Apresentada a descrição do pólen de algumas espécies.

Summary A taxonomic revision of the Amazonian species of Rhizophoraceae was made. There are 5 genera and 12 species represented in the area. No new taxa were found and several existing names were reduced to synonomy. Comments are given on the relationship of various species and the distribution of each species is given on maps. Some information about the polen grains is given too.