The shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora.

ResumoA família Hydrocharitaceae é cosmopolita; composta por 17 gêneros e 127 espécies. São ervas aquáticas fixas ou livres, flutuantes, submersas ou emersas, em água doce, salobra ou salgada. No Brasil ocorrem seis gêneros e cerca de 15 espécies. A fim de conhecer a real diversidade da família no estado do Rio de Janeiro foi realizado o levantamento em herbários e coletas. Registraram-se seis espécies autóctones e duas alóctone em cultivo. Apalanthe granatensis, encontrada em represas, rios e lagoas de água doce, possui flores bissexuais. Egeria densa, semelhante a A. granatensis, distingue-se pelas flores unissexuais. Halophila decipiens, ocorre em praias da Baia de Guanabara; caracteriza-se pelo caule rizomatoso e folhas elípticas. Limnobium laevigatum, ocorre flutuando livremente em lagoas e emersa em alagados, possui folhas flutuantes com espessamento aerenquimatoso abaxial e/ou folhas emersas sem espessamento. Najas arguta var. arguta, exibe caule inerme, folhas concentradas no ápice dos ramos e semente fusiforme, Najas marina, apresenta dentes no caule e nervura principal e semente elíptica; ambas encontradas em lagoas costeiras. Elodea canadensis e Vallisneria sp. foram encontradas em cultivo. Palavras-chave: flora do Sudeste do Brasil, Mata Atlântica, Najadaceae, plantas aquáticas. AbstractHydrocharitaceae is a cosmopolitan aquatic group that comprises 17 genera with 127 species. The individuals are herbs fixed or free, floating, submerged or emerged living in fresh, brackish or salty water. In Brazil, it is represented by six genera and ca. 15 species. Aiming to know the real diversity of the family in Rio de Janeiro state, a study of herbaria collection and an extensive field work were made. Six native and two introduced species were registered. Apalanthe granatensis, presents bisexual flowers and was found in dams, rivers and freshwater ponds. Egeria densa, is similar to A. granatensis, and can be distinguished by the unisexual flowers. Halophila decipiens, occurs in the Guanabara Bay beaches, it is characterized by rhizomatous stem and elliptical leaves. Limnobium laevigatum. Heine is a free floating herb found in ponds and emerged in marshes, it has floating leaves with abaxial aerenchymatous thickening and/or emerged leaves without thickening. Najas arguta var. arguta exhibits spineless stem, leaves concentrated at the apex of the branches and fruit with fusiform seed, and Najas marina has thorns on the stem and midrib, and elliptical seed. Both are found in coastal lakes. Elodea canadensis and Vallisneria sp. were found under cultivation. Key words: Southeast Brazilian flora, Atlantic Forest, Najadaceae, aquatic plants. Hydrocharitaceae Juss. Ervas aquáticas, submersas, flutuantes ou emersas, fixas ou livres, anuais ou perenes; monoicas ou dioicas. Raiz simples ou ramificada. Caule monomórfico, dimórfico ou polimórfico, estolonífero e/ou ereto, alongado ou contraído, rosulado ou não. Folhas dísticas, subopostas ou verticiladas, pecioladas ou sésseis; lâmina glabra ou pilosa, orbicular a linear, m...

Resumo Lemnoideae (Araceae) são ervas aquáticas flutuantes, extremamente reduzidas. Subcosmopolitas, geralmente são encontradas em ambientes lênticos de regiões tropicais. No Brasil ocorrem 15 espécies. Este estudo deslindou a subfamília Lemnoideae no estado do Rio de Janeiro, com base em trabalhos de campo e visitas a herbários. Foram registradas onze espécies: Landoltia punctata ocorre na restinga, floresta ombrófila, vegetação secundárias e áreas urbanizadas; Lemna aequinoctialis é amplamente distribuída no estado, ocorre na restinga, floresta ombrófila, vegetação secundárias e áreas urbanizadas; Lemna minuta e Lemna valdiviana ocorrem em restinga e floresta ombrófila; Spirodela intermedia e Wolffia arrhiza ocorrem apenas na restinga; Wolffia brasiliensis ocorre na restinga e floresta ombrófila; Wolffia cylindracea foi encontrada em vegetação secundária; Wolffia globosa ocorre em floresta ombrófila; Wolffiella neotropica e Wolffiella lingulata ocorrem apenas na restinga. Este trabalho disponibiliza descrições morfológicas, chaves de identificação, ilustrações e outras informações das espécies de Lemnoideae ocorrentes no Rio de Janeiro. As buscas em campo e a análise dos materiais revelaram três novas ocorrências para o estado e duas para o Brasil.

A new species of Lophogyne from a Brazilian Amazon savanna is described and illustrated. It is morphologically similar to the former Jenmaniella species, due to the presence of stems that arise from prostrate roots attached to the substratum, a gynophore at anthesis, and three prominent non-suture ribs per valve in the fruit, currently merged in Lophogyne s.l.. Lophogyne wilsonii can be distinguished from all others species of  Lophogyne s.l. by the apical region of the roots unattached from the substratum. The conservation status is discussed and an identification key is presented.