Paulo Günter Windisch

Diversity of ferns and lycophytes in Brazil

This compilation of ferns and lycophytes in Brazil is an update of the one published in 2010 in Catalogo de Plantas e Fungos do Brasil. The methodology consisted in collecting data from regional checklists, taxonomic revisions, and selected databases. Invited specialists improved the list accessing a website housed at the Jardim Botânico do Rio de Janeiro. The results show 1,253 species: 1,111 of ferns and 142 of lycophytes. This number is 6.5% higher than the previous one (1,176 spp.). The percentage of endemic species decreased from 38.2% to 36.7%. We recognized 36 families and 133 genera (vs. 33 families, 121 genera in 2010). The 10 most diverse families are Pteridaceae (196 spp.), Dryopteridaceae (179), Polypodiaceae (164), Hymenophyllaceae (90), Thelypteridaceae (86), Aspleniaceae (78), Lycopodiaceae (64), Selaginellaceae (55), Anemiaceae (51), and Cyatheaceae (45). The three most diverse genera are still Elaphoglossum (87 spp.), Thelypteris (85), and Asplenium (74). The richest phytogeographic domain continues to be in the Atlantic Rainforest with 883 species which also has the largest number of endemic and threatened species, followed by the Amazon Rainforest (503), Cerrado (269), Pantanal (30), Caatinga (26), and Pampa (eight). Minas Gerais remains as the richest state (657 spp. vs. 580 in 2010).

Caudex growth and phenology of Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) in secondary forest, southern Brazil

The leaf production and senescence, formation and release of spores of Cyathea atrovirens (Langsd. & Fisch.) Domin were analysed based on the monthly monitoring of 50 plants growing in a secondary forest, in the municipality of Novo Hamburgo, in the state of Rio Grande do Sul, during the year 2004. The caudex height and number of mature and fertile leaves were recorded annually in 2004-09. In 2004, monthly production and senescence of leaves were concomitant, without total leaf abscission. Population synchrony at emergence (Z = 0.86) and leaf senescence (Z = 0.82) increased in spring but did not correlate with temperature and photoperiod. All individuals were fertile and the sporangia production and spore liberation presented higher and equal synchrony (Z = 0.84) respectively in spring and summer. Sporangia production was related with temperature and photoperiod, however taller plants did not produce more fertile leaves. Phenological events analysed were not influenced by precipitation, as expected for forests in non-seasonal climate. Over five years (2004-09), the annual mean caudex growth varied between 1.19 and 2.50 cm.year-1 and the plants appeared to have an ability to maintain a relatively stable amount of leaves throughout this period.

Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae)

Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyers medium. Cultures were maintained in a growth chamber at 24 +/- 1 degrees C, under artificial light with nominal irradiance of 110 micromol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48%, respectively), compared with the control (68%). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.

Crescimento do cáudice e fenologia de Dicksonia sellowiana Hook. (Dicksoniaceae) no sul do Brasil

In Southern and Southeastern Brazil, the tree fern Dicksonia sellowiana Hook. still is illegally extracted from remnants forests for the use of its fibrous caudex cover, as well as for cultivation as an ornamental plant. In the present study the caudex growth, frond production, expansion and senescence as well as the formation and release of spores have been studied based on the observation of 37 plants. During an observation period of one year, the caudexes grew at an average of 5.65 cm year-1 and the growth rate presented a strong correlation with the height of the plants. Similar frond production rate (10.86 fronds year-1) and senescence (10.54 fronds year-1) evidenced the capacity of maintaining a stable number of fronds throughout the year. Only 14 individuals developed fertile fronds, most of them producing spores during the summer and liberating them during the winter. Production and release of spores were influenced more by temperature and photoperiod rather than by rainfall.

Vittariaceae (Pteridophyta) do Sudeste do Brasil

A floristic and taxonomic study of the family Vittariaceae in southeastern Brazil is presented. Seven of the ten genera, which comprise this family, are American. Five genera and nine species occur in the studied region: Anetium Splitg. and Hecistopteris J. Sm. with one species each; Polytaenium Desv. with three species; Radiovittaria (Benedict) E.H. Crane and Vittaria Sm. with two species each. Identification keys for genera and species are presented. The studied species are described and illustrated, and taxonomic and ecological commentaries were included.

Lycopodiaceae in Brazil. Conspectus of the family I. The genera Lycopodium, Austrolycopodium, Diphasium, and Diphasiastrum

A conspectus of the Lycopodiaceae in Brazil is presented, following a generic classification based on anatomy, chromosome numbers, spores and gametophytes, as well as recent molecular studies. The species of Lycopodiaceae occurring in Brazil, traditionally treated conservatively, were grouped in three genera: Lycopodium, Lycopodiella, and Huperzia. Within each genus, the diversity (treated under various subgenera, sections, and subsections) has been discussed. In our new approach, these three genera are treated as subfamilies Lycopodiodeae (four genera in Brazil), Lycopodielloideae (three genera in Brazil), and Huperzioideae (two genera in Brazil). Branching patterns and morphological diversity of vegetative leaves and sporophylls, as well as morphology of sporangia and spores in the different groups, are discussed in a brief review. We provide keys to identification of subfamilies and genera represented in Brazil. The species of Lycopodioideae, genera Lycopodium (s.str.), Austrolycopodium, Diphasium, and Diphasiastrum (one species in the first three genera, two in Diphasiastrum - one of them new) are treated in detail, with descriptions, illustrations (or references to illustrations), and comments on habitat and distribution.

Germination and sporophytic development of Regnellidium diphyllum Lindman (Marsileaceae) in the presence of hexavalent chromium

Regnellidium diphyllum Lindman is a heterosporous fern, growing in aquatic environments and surrounding wetlands, which is assumed to be threatened by increasing water pollution and disappearance of its natural habitats. Among contaminants, hexavalent chromium - Cr(VI) - is known to be present in effluents from some leather tanning factories. Megaspore germination tests were performed using Meyers solution, at concentrations 0 (control), 0.1, 0.5, 1, 5, 10, 15, 20, 30, 50, and 80 mg.L⁻¹, from a standard solution of Titrisol® 1000 mg.L⁻¹. The primary development of apomictic sporophytes was studied using solutions containing 0.025 to 4.8 mg.L⁻¹ of Cr(VI). The experiments were conducted in a growth chamber at 24 ± 1 ºC and for a 12-hour photoperiod under fluorescent lights, providing a nominal irradiance of 77 µmol.m⁻²/s. Significant differences in megaspore germination, with subsequent sporophytic development, were verified from 0.5 mg.L⁻¹ Cr(VI) concentration onwards. Growth of primary root and primary and secondary leaves was significantly reduced at 3.2 mg.L⁻¹ Cr(VI) concentration or higher. Considering the pollution from Cr(VI) in some areas of R. diphyllum natural occurrence, these data indicate that low reproductive rates and disappearance of populations are likely to occur in these situations.

O gênero Thelypteris (Thelypteridaceae, Polypodiopsida) no Estado do Mato Grosso, Brasil: I: subgêneros Goniopteris (C.Presl) e Meniscium (Schreb.) C.F. Reed

Thelypteridaceae Pic.Serm. is represented in the state of Mato Grosso, by the genera Macrothelypteris and Thelypteris, the latter represented by five subgenera Amauropelta (Kunze) A.R. Smith, Cyclosorus (Link) C.V. Morton, Goniopteris (C.Presl), Meniscium (Schreb) C.F.Reed and Steiropteris Iwats. This study discusses the representatives of the subgenera Goniopteris (C.Presl) Duek (six species, including one probable occurrance in the state) and Meniscium (Schreb.) C.F.Reed (six species). Identification keys, descriptions, references to illustrations with diagnostic characters are presented together with comments on geographic distribution.

Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae).

The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyers solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L(-1) of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L(-1) of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L(-1) of Ni, when compared with the treatment without this metal. At 4.8 mg L(-1), leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species.

Diversity and Distribution Patterns of Aspleniaceae in Brazil

The family Aspleniaceae is represented in Brazil by two genera: Asplenium, with 69 species and four varieties and Antigramma, with three species. The genus Asplenium is widely distributed in the tropical and subtropical regions and presents 20 species that occur exclusively in Brazil. The genus Antigramma is mainly Neotropical, represented in this region by three species, one of them restricted to Brazil. The pantropical elements constitute 9.2%, the widely distributed in America 32.9%, the widely distributed in South America 4%, the restricted to the northern part of South America 11,8%, and those restricted to the meridional part of South America 11.8%. Species restricted to Brazil correspond to 27.6%, and are centered exclusively in the South and Southeastern regions. Two species (2.7%) represent disjunctions, one also occurring in the Andes and the other in the Guaianas. An analysis of the group in relation to the Neotropical fern diversity and speciation centers indicates that the majority of the taxa (78%) occur in she Southeastern Brazilian center. The Andean center presents significant relations with the Brazilian fern flora, followed by elements from the Guaianas and Mexico/Central America. The results reaffirm the importance of South-Southeastern Brazil as a major center of speciation and endemism for Neotropical ferns, especially the regions of the Atlantic forest and “campos rupestres” (rupestrial grasslands). Distribution maps of some species are presented with a discussion of the distribution patterns.