Ricardo de S. Secco

Chemical constituents and allelopathic and antioxidant activities of Alchorneopsis floribunda Müll. Arg. (Euphorbiaceae)

Chemical investigation of extracts from the stems and leaves of Alchorneopsis floribunda Müll. Arg., collected in the Amazon region, was performed. The main isolated compounds were triterpenes (α-amyrin, β-amyrin, lupeol, betulin, betulinic acid, uvaol, erythrodiol and oleanolic acid) and phenolic acid derivatives from 4-hydroxybenzoic acid (gallic and protocatechuic acids and isocorilagin). In the germination assays, high inhibitory allelopathic effects of the extracts and isocorilagin were observed and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of isocorilagin was higher than those of the standards used (Trolox and butylated hydroxyanisole). This is the first chemical study of the genus Alchorneopsis (Euphorbiaceae).

A importância da identificação botânica nos inventários florestais: o exemplo do "tauari" (Couratari spp. e Cariniana spp. - Lecythidaceae) em duas áreas manejadas no estado do Pará

The vernacular names usually used in commercial inventories may group together distinct species. To investigate this problem, the botanical identification of trees called Tauari were examined were examined in commercial inventories of 100 ha located in the central and eastern lumber regions of the State of Para. Field characters of each species were noted. Information about the relative distribution of this species, the technological characteristics of the timber of each species and Brazil’s federal laws relating to forest management is discussed. In the central region, 112 individuals were recorded as Couratari guianensis and six individuals as Couratari sp. After revision, using botanical material collected from each tree and identified using herbarium material, the following species listed as Couratari guianensis were found: Couratari guianensis, C. oblongifolia and C. stellata (the most abundant) and specimens listed as Couratari sp. included both Cariniana micrantha and C. decandra. In the eastern region, 33 individuals were recorded by the company as Couratari guianensis, but the scientific identification showed the existence of two species: C. guianensis (the most abundant) and C. oblongifolia. C. tauari also was seen growing nearby. This study shows that correct determination of the can be obtained from field characters (leaves, branches and trunks). Botanical identification is demonstrated as fundamental for the knowledge of the regional diversity and essential for successful management plans.

An overview of recent taxonomic studies on Euphorbiaceae s.l. in Brazil

As Euphorbiaceae sensu lato distribuem-se especialmente nos tropicos, nos mais variados tipos de vegetacao e habitats, sendo uma das maiores, mais complexas e diversificadas familias das Angiospermas. Foi recentemente dividida em quatro familias e segundo os atuais sistemas de classificacao, baseados em estudos filogeneticos envolvendo dados moleculares, esta assim classificada: Euphorbiaceae sensu stricto, Phyllanthaceae, Putranjivaceae e Picrodendraceae, havendo uma proposicao de estabelecer Peraceae, taxon ainda em discussao. Houve tambem mudancas no posicionamento taxonomico de generos de ampla distribuicao no territorio brasileiro, tais como Amanoa, Drypetes, Pera, Phyllanthus, Podocalyx, Pogonophora e Richeria, entre outros. Alem disso, novas especies vem sendo propostas e a amplitude dos limites de distribuicao de diversos taxons vem aumentando no Brasil. Diante do exposto, os autores fornecem um panorama geral dos estudos mais recentes e avancos na taxonomia de Euphorbiaceae s.l. nas regioes Norte, Nordeste, Sudeste e Sul do pais, concentrando-se nos trabalhos de revisao e floras regionais, bem como nas mudancas que resultaram em nova configuracao taxonomica da familia.

Sinopse das espécies de Marlierea Cambess. (Myrtaceae) na Amazônia brasileira

A morphological study of Marlierea Cambess. occurring in Amazonian Brazil was carried out in order to obtain a better understanding of the morphology and taxonomy of all species in the region and to provide data to elucidate the taxonomic segregation of Marlierea from the morphologically similar Myrcia DC. ex Guill. In Amazonian Brazil, Marlierea is represented by 11, primarily forest, species (Marlierea bipennis (O. Berg) McVaugh, M. caudata McVaugh, M. ensiformis McVaugh, M. ferruginea (Poir.) McVaugh, M. mcvaughii B. Holst, M. scytophylla Diels, M. spruceana O. Berg, M. subulata McVaugh, M. summa McVaugh, M. umbraticola (Kunth) O. Berg, and M. velutina McVaugh). The taxonomically problematic M. obumbrans (O. Berg) Nied. is discussed as a badly known species. The species are trees or shrubs with opposite leaves (sometimes alternate in M. velutina); inflorescences racemose or paniculate (in panicles, cymes, or dichasiums), sometimes in fasicles; flower buds generally closed; calyx lobes 4-5, opening irregularly; and petals frequently absent. The states of Amazonas and Para are the most species-rich. Marlierea spruceana and M. umbraticola are the most common species. Additional studies of M. obumbrans, morphologically intermediate between Marlierea and Myrcia, will be untaken in the future in order to establish the correct taxonomic placement of this enigmatic species.

Croton dissectistipulatus, a new species of Euphorbiaceae from Amazonian Brazil

A new species ofCroton,C. dissectistipulatus, is described from Amazonian Brazil. This species is superficially similar toC. timandroides from northeastern and southeastern Brazil, but differs in having petiolate leaves with glandular margins, persistent stipules, conspicuous racemose inflorescences, staminate flowers having externally glabrous sepals and 3 stamens, and pedicellate pistillate flowers. The systematic position ofC. dissectistipulatus relative to the sections ofCroton is discussed.ResumenUma nova espécie deCroton da Amazônia brasileira,C. dissectistipulatus, é descrita. Essa espécie é superficialmente semelhante aC. timandroides, do nordeste e sudeste do Brasil, mas separa-se por apresentar folhas pecioladas, com as margens glandulosas, estípulas persistentes, inflorescências em racemos, conspícuas, flores estaminadas com sépalas glabras externamente, estames 3 e flores pistiladas pediceladas. A posição sistemática deC. dissectistipulatus em relação às seções deCroton é discutida.

As espécies de Pera (Euphorbiaceae s.s) na Amazônia brasileira

Pera Mutis is an endemic genus from the Neotropics, with about 30 species and diversity center located in the Amazon. These species are trees or shrubs, dioecious or rarely monoicous, having globose bracts that are sometimes confused with floral buds. The last revision of this genus was in 1919, and many species have been described since then. This work aims to carry out a taxonomic study of Pera species that occur in the Brazilian Amazon and discussing the position of genera as part of an autonomous taxon (Peraceae) or if a member of the Euphorbiaceae s.s. Thirteen species in the Brazilian Amazon were found: Pera anisotricha Mull. Arg., P. bicolor (Klotzsch) Mull. Arg., P. benensis Ruby, P. coccinea (Benth.) Mull. Arg., P. decipiens Mull. Arg., P. distichophylla (Mart.) Baill., P. eiteniorum Bigio & Secco, P. glabrata (Schott) Baill., P. heteranthera (Schranck) I. M. Johnst, Pera manausensis Bigio & Secco P. membranacea Leal, P. tomentosa (Benth.) Mull. Arg., P. pulchrifolia Ducke. From these species, three are new records for the Brazilian Amazon. Eight taxa were considered to be new synonyms and new lectotypes were designated. Data on the history of the genus, and on morphology and biology, as well as descriptions, identification keys, and illustrations of the species are presented.

O gênero Galeandra (Orchidaceae) na Amazônia Brasileira

This paper is an inventory of species of the genus Galeandra Lindl. in the Brazilian Amazon. The occurrence of seven species was confirmed: G. baueri Lindl., G. cu bw rvifolia Barb. Rodr., G. devoniana Schomb. ex Lindl., G. lacustris Barb. Rodr., G. montana Barb. Rodr., G. stangeana Rchb.f. and G. stillomisantha (Vell.). Galeandra baueri was considered a new record for the flora of Brazil. Although G. beyrichii Rchb.f and G. paraguayensis Cogn. do not occur in the Brazilian Amazon, they were included in the paper because they occur in areas belonging to the Legal Amazon. Identification key, descriptions and illustrations are presented, as well as comments on the geographical distribution, habitat and aspects of phenology for the studied species.

Mimosa dasilvae, uma nova Mimosaceae da Amazônia Brasileira

A new species of Mimosaceae from Brazilian Amazon, called Mimosa dasilvae A. S. Silva & R. Secco is described and illustrated. The new taxon belongs to sect. Habbasia ser. Piresianae and shows affinities with M. piresii Barneby, from which differs specially in long, liana-like habit, smaller, ventrally glabrous and lustrous leaflets, and very small floral bracts.

A New Species of Phyllanthus (Phyllanthaceae) Endemic to Amazonas State, Brazil

Abstract.  A new species of Phyllanthus L., P. aracaensis G. L. Webster ex Secco & A. Rosário (Phyllanthaceae), probably endemic to Amazonas State, is described and illustrated. In terms of its habit and overall appearance it is superficially close to P. myrsinites Kunth, a species with variable leaf morphology, which is widely distributed throughout the Amazon region. The new species may be distinguished from P. myrsinites by its orbicular leaves without a subapical gland on the abaxial face, staminate flowers isolated or in pairs with sepals free, stamens with partially joined filaments at base, and style with branches joined, apically free, trifid.

A New Species of Pera (Euphorbiaceae) from Amazonian Brazil

Abstract.  A new species of Euphorbiaceae from the Brazilian Amazon, Pera eiteniorum Bigio & Secco, is described and illustrated. This species is closely related to P. tomentosa (Benth.) Müll. Arg., P. membranacea Leal, and P. heteranthera (Schrank) I. M. Johnst., but can be distinguished from them by the following characteristics: the abaxial leaf surface with stellate trichomes and the blade midvein with stellate-lepidote trichomes, staminate flowers with the calyx glabrous or rarely with sparse, sericeous trichomes, and a well-developed rudimentary pistillate flower with a lageniform (flask-shaped) ovary, triangular stigma, and narrowly oblanceolate staminode. Affinities of the new taxon are discussed, and a key to morphologically similar species from Amazonian Brazil is presented.