Papers by Maria das Graças Sajo
Considering that the root structure of the Brazilian genera belonging to the Catasetinae subtribe... more Considering that the root structure of the Brazilian genera belonging to the Catasetinae subtribe is poorly known, we describe the roots of twelve representatives from this subtribe. For anatomical analysis, the roots were fixed in FAA 50, preserved in ethanol 70% and sectioned at its medium region using razor blades. The sections were stained with 0.05% astra blue and safranin and mounted in glycerin. For the identification of starch we used Lugol´s solution; for lignin, floroglucin chloridric; for lipids, Sudan III, and for flavanoids, potassium hydroxide. The relevant aspects were registered using a digital camera joined with an Olympus microspope (BX51 model). The structural similarities of all roots support the placement of the subtribe Catasetinae into the monophyletic tribe Cymbidieae. Some root features are restricted to one or two taxa and can be useful in the systematics of the subtribe. For example, the occurrence of flavonoidic crystals characterizes the genera Catasetum and Cychnodes, and the number of the velamen layers and the shape of the epivelamen cells are useful to confirm the taxonomic position of Clowesia amazonica. The presence of velamen and flavonoidic crystals was interpreted as an adaptation to the epiphytic habit.
Boletim de Botânica, 1992
Acta Botanica Brasilica
The user has requested enhancement of the downloaded file. Acta boI. bras. 10(2):1996 379 NOTAS T... more The user has requested enhancement of the downloaded file. Acta boI. bras. 10(2):1996 379 NOTAS TAXONÔMICAS EM XYRIS L. (XYRIDACEAE) Maria das Graças Lapa Wanderleyl Maria das Graças Sajo2 Recebido em 4/11/96. Aceito em 30/12/96. RESUMO-(Notas taxonômicas emXyris L. (Xyridaceae». São propostas alterações nomenclaturais e taxonômicas em Xyris, status novum e dois novos sinônimos. Palavras-chave: Xyridaceae, Xyris, status novo, novos sinônimos ABSTRACT -(Taxonomic notes in Xyris L. (Xyridaceae». Nomenclatural and taxonomic changes are proposed in Xyris; one new status and two new synonym.
Acta Botanica Brasilica
We studied the leaf vasculature and the petiole anatomy of 22 species of Melastomataceae from the... more We studied the leaf vasculature and the petiole anatomy of 22 species of Melastomataceae from the cerrado of the São Paulo State, Brazil. In all the representatives, the leaf venation is of the acrodromous pattern, but some features, such as the kind of areolation, the number of primary and secondary veins, the type of marginal ultimate venation, and the arrangement of the vein nets, can be related to the tribe and genera that the species belongs. Some aspects of the petiole structure, such as its outline, the distribution of the vascular bundles and the epidermal features, are also useful to characterize the genera. The variation observed on leaf venation and on petiole anatomy are described and discussed under a taxonomic point of view.
Revista Brasileira de Botânica, 2003
Leaf structure of Aechmea Ruiz & Pav. subgenus Lamprococcus (Beer) Baker and related species (Bro... more Leaf structure of Aechmea Ruiz & Pav. subgenus Lamprococcus (Beer) Baker and related species (Bromeliaceae)). With the aim of recognising useful features for taxonomic purposes, we studied the leaf anatomy of 25 taxa that are morphologically related (13 of Aechmea subgenus Lamprococcus, three of Ronnbergia E. Morren & André, four of Araeococcus Brongn. and five of Lymania Read). Although all leaves are hypostomatic and have a dorsiventral mesophyll with a hypodermis, they show some features that characterise each species. These features include, the stomata position on leaf surface, the presence or absence of substomatic occlusions, the occurrence or not of fibre clusters in the mesophyll, the nature of the cell walls of the vascular bundle sheaths and the cell morphology of the diaphragm that interrupt the air channels. By associating these characters we have elaborated an identification key for the studied taxa, based on the leaf structure.
Revista Brasileira de Botânica, 2008
Anatomy of the floral scape of Bromeliaceae). This paper describes the anatomy of the floral scap... more Anatomy of the floral scape of Bromeliaceae). This paper describes the anatomy of the floral scape for 12 species of Bromeliaceae, belonging to the subfamilies Bromelioideae, Tillandsioideae and Pitcairnioideae. Although all the scapes have a similar organization, there are variations in the structure of the epidermis, cortex and vascular cylinder. Such variations are described for the studied scapes and, when considered together they can help to identify the species. These aspects are described for each scape and discussed under a taxonomic point of view.
Plant Systematics and Evolution, 2008
Reproductive morphology and development are described in the Brazilian grass Streptochaeta spicat... more Reproductive morphology and development are described in the Brazilian grass Streptochaeta spicata, in order to assess the homologies of the characteristic grass inflorescence, termed a spikelet, and other reproductive organs. Streptochaeta possesses some features that are commonly found in Poaceae, including a well-differentiated embryo. It also possesses some relatively unusual, presumably derived features, such as non-plumose stigmas, which indicate that it could be insect-pollinated. It shares some features with other early-divergent grasses, such as Pharus, which could represent plesiomorphic conditions for grasses. The inflorescence unit in Streptochaeta has been interpreted as a compound branching system or pseudospikelet. The present data suggest that it is a highly modified spikelet, with a modified flower borne either on a different axis to the basal bracts (glumes) or on the same axis as the basal bracts. The three bracts below the stamens are interpreted as homologous to the lodicules. The Streptochaeta spikelet could be considered as morphologically intermediate between the true spikelet of grasses and reproductive units of close grass relatives.
International Journal of Plant Sciences, 2007
A detailed study of floral ontogeny, anatomy, and embryology in two (of six) species of Pharus is... more A detailed study of floral ontogeny, anatomy, and embryology in two (of six) species of Pharus is presented as part of a series of comparative investigations on early-divergent grasses. Pharus is a taxonomically isolated genus belonging to the earliest-diverging grass lineage with a true grass spikelet. It is unusual in possessing remarkably dimorphic florets: male florets possess two lodicules, six stamens, and a pistillode, whereas female florets lack lodicules entirely but possess six staminodes and a tricarpellary ovary with three stigmas. The rudimentary lodicules in male florets are initiated after the stamen whorls. There are most commonly six androecial organs, but in some florets, a five-staminate condition was observed, resulting from suppression of the abaxial stamen from the inner whorl, or even a four-staminate condition resulting from subsequent fusion of the two adaxial outer stamens (i.e., elements of both whorls). Thus, the pattern of floral zygomorphy in Pharus differs from that of many other grasses. Centrifixed anther attachment is reported for the first time in Pharus, resembling the condition in another early-divergent grass, Anomochloa, though anthers are introrse in Anomochloa compared with latrorse in Pharus. Anther wall development is of the reduced type in Pharus, in contrast to most other monocots. Microsporogenesis is of the successive type, as in many other monocots. The ovary develops from three distinct primordia and is unilocular with a single ovule and a pronounced ovary beak that is highly characteristic of Pharus. There is a hollow style, in contrast to the solid styles that are common in many other grasses. The embryo is highly differentiated, as in other grasses, with a distinct epiblast and a small cleft between the scutellum and the coleorhiza.
Acta boI. bras, 2000
RESUMO-(Aspectos morfo-anatômicos de três espécies de Drosera, durante o desenvolvimento pós-semi... more RESUMO-(Aspectos morfo-anatômicos de três espécies de Drosera, durante o desenvolvimento pós-seminal). Durante o processo de germinação, as sementes das três espécies (Drosera spalhulala Labil\., D. lizlermedia Dreves & Hayne e D. bltrmalllziVahl) ...
Acta Botanica Brasilica, 2004
Acta Botanica Brasilica, 2007
Recebido em 20/07/2006. Aceito em 21/12/2006 RESUMO -(Anatomia foliar de bromélias ocorrentes em ... more Recebido em 20/07/2006. Aceito em 21/12/2006 RESUMO -(Anatomia foliar de bromélias ocorrentes em áreas de cerrado do Estado de São Paulo, Brasil). Visando apontar características inerentes à família Bromeliaceae e indicar possíveis adaptações anatômicas encontradas nas espécies de cerrado, foram estudadas as folhas de cinco Bromelioideae, sete Tillandsioideae e uma Pitcairnioideae. Em geral, nas Bromelioideae, os estômatos estão aprofundados na epiderme e verifica-se um tecido mecânico epidérmico e subepidérmico; observa-se um tecido parenquimático armazenador de água, células esclerificadas não relacionadas aos tecidos vasculares, além de canais de aeração percorrendo longitudinalmente o mesofilo. Nas Tillandsioideae, as folhas são densamente recobertas por escamas, os estômatos ocorrem nas duas superfícies e o mesofilo é bastante compacto. Em Pitcairnioideae, a estrutura foliar é bastante semelhante à das Bromelioideae, embora os estômatos sejam ligeiramente elevados em relação à epiderme e não ocorram grupos de células esclerificadas extravasculares. Os resultados foram avaliados dentro de um contexto adaptativo e taxonômico.
Revista Brasileira de Botânica, 2004
Foliar ontogeny of three species of Erythroxylum P. Browne (Erythroxylaceae) from Cerrado). Leave... more Foliar ontogeny of three species of Erythroxylum P. Browne (Erythroxylaceae) from Cerrado). Leaves of Erythroxylum campestre, E. nanum, and E. tortuosum have been studied in different developmental stages in order to describe the leaf ontogeny and the structure of scars found in mature blades of Erythroxylum. The marginal growth of the leaves is of the "median submarginal" type. At early stages, intense activity in the adaxial meristem leads to the formation of a crest on this surface, while the laminar portion has an involuted aspect, due to the activity of the marginal meristem. The stomata develop at the same time as the mesophyll layers and the final expansion of the blade results from an intercalary growth. Blade scars were not observed during ontogeny. When present these scars appear to result from shallow injuries parallel to the midrib on the abaxial surface.
Boletim de Botânica, 1979
International Journal of Plant Sciences, 2015
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, a... more JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].
Revista Brasileira de Botânica, 2004
Vasculature and identification of Eugenia (Myrtaceae) from the bank of Tibagi river, State of Par... more Vasculature and identification of Eugenia (Myrtaceae) from the bank of Tibagi river, State of Paraná). With the objective of recognizing vegetative helpfull characteristics in the Myrtaceae identification, we studied the leaf anatomy of 17 species of Eugenia, from the bank of Tibagi river, State of Paraná. Using leaf blade venation and, the pattern of the petiole vascular bundle sheaths we separated the species in three different groups. The camptodromous-brochidodromous venation pattern occur in nine species, the acrodromous pattern in four species, and a mixed pattern in four species. Depending on the species, the petiole vascular bundle sheaths can be of parenchymatous, sclerenchymatous or mixed nature. A dicotomic identification key was elaborated with these vegetative characters showing that they can surely aid in the Eugenia species identification.
International Journal of Plant Sciences, 2014
Premise of research. The Neotropical family Cyclanthaceae is one of five families of the order Pa... more Premise of research. The Neotropical family Cyclanthaceae is one of five families of the order Pandanales, which includes some misfit taxa that are morphologically highly anomalous. In the taxonomically isolated genus Cyclanthus, which is sister to all other Cyclanthaceae, individual flowers are not readily distinguishable. Instead, flowers are replaced by discoidal rings that encircle the inflorescence. We compare features that are shared among misfit taxa.
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Papers by Maria das Graças Sajo