Silica bodies and their systematic implications at the subfamily level in Podostemaceae

Abstract

Podostemaceae is a family of eudicotyledonous rheophytes with unique morphology, sometimes resembling algae, lichens or bryophytes. This study evaluates the taxonomic value of silica-body morphology (presence, location, size, shape, ornamentation) in species representing the three subfamilies: Tristicha trifaria (Bory ex Willd.) Spreng. (Tristichoideae), Weddellina squamulosa Tul. (Weddellinoideae) and Diamantina lombardii Novelo, C.T.Philbrick & Irgang (Podostemoideae). T. trifaria and D. lombardii have silica bodies in stems and leaves. In contrast, W. squamulosa exhibits silica bodies only in the scale-like leaves. The morphology of these bodies is unique to each species. The results denote the taxonomic usefulness of silica characteristics and a need for a more complete study of silica bodies throughout the family. Key words: aquatic plants, Podostemaceae, silica bodies. ResumoPodostemaceae é uma família eudicotiledônea reófita de morfologia peculiar, lembrando por vezes algas, liquens ou briófitas. O presente estudo avalia o valor taxonômico da morfologia dos corpos silicosos (presença, localização, tamanho, forma e ornamentação) em espécies representantes das três subfamílias: Tristicha trifaria (Bory ex Willd.) Spreng. (Tristichoideae), Weddellina squamulosa Tul. (Weddellinoideae) e Diamantina lombardii Novelo, C.T.Philbrick & Irgang (Podostemoideae). T. trifaria e D. lombardii apresentam corpos silicosos nos caules e nas folhas, enquanto W. squamulosa possui estas estruturas restritas às folhas escamiformes. A diversidade morfológica dos corpos silicosos, específica para cada espécie aqui estudada, comprova o potencial taxonômico deste caráter, até então negligenciado, e aponta para a necessidade de estudos mais abrangentes para essas estruturas em Podostemaceae. Palavras-chave: corpos silicosos, plantas aquáticas, Podostemaceae.

Silica bodies in leaves of neotropical Podostemaceae: taxonomic and phylogenetic perspectives

“…The transformation series presenceabsence-presence of silica bodies, as observed here, was also reported for Commelinales by Prychid et al (2003b). Our results confirm the presence of silica bodies in five species that have already been reported in the literature: Apinagia richardiana (Schnell, 1967), Diamantina lombardii (Rutishauser et al, 2005;da Costa et al, 2011), Mourera aspera (Warming, 1888), Tristicha trifaria (Cario, 1881;Costa et al, 2011) and Weddellina squamulosa (Wächter, 1897;da Costa et al, 2011). We added new data for 19 species, in addition to the 16 species analysed that do not possess silica bodies.…”

“…The taxonomic relevance of the presence, location and form of silica bodies in angiosperms, and their use as informative characters at several taxonomic ranks, is highlighted by many studies (e.g. Brown, 1984;Prychid et al, 2003a;da Costa et al, 2011). The majority of these studies have focused on monocot families, such as Cyperaceae and Poaceae (e.g.…”

“…Little has been proposed regarding the use of silica bodies in terms of taxonomic and phylogenetic perspectives in Podostemaceae (Table 1). da Costa et al (2011) concluded that shape and surface morphology of silica bodies are valuable taxonomic characters at the subfamily level in Podostemaceae, and emphasized the need for further investigations to evaluate their utility at lower hierarchical ranks. Lopes (2012) analysed the vegetative anatomy of eight neotropical species (five of them in Podostemum) from three genera, and concluded that these species can be distinguished by the shape of their silica bodies.…”

Estágio atual do conhecimento sobre fitólitos no Brasil

“…A caracterização dos tipos morfológicos apontou a predominância de formas "Globular echinate", sendo encontrado em todas as estruturas da planta e em maior quantidade, portanto caracterizados como padrão para a família Arecaceae. Costa et al (2011) realizou uma análise aprofundada da formação dos corpos silicosos em plantas das subfamílias de Podostemaceae. Calegari et al (2011) no trabalho publicado no encontro da ABEQUA (Associação Brasileira de Estudos do Quaternário) faz uma primeira aproximação dos principais morfotipos de fitólitos presentes em um fragmento de Floresta Ombrófila Mista e Campo presente no Sudoeste do Estado do Paraná, tema posteriormente aprofundado pela dissertação de Raitz (2012).…”

The Lowermost Tejo River Terrace at Foz do Enxarrique, Portugal: A Palaeoenvironmental Archive from c. 60–35 ka and Its Implications for the Last Neanderthals in Westernmost Iberia

“…Coverslips were fixed using Entelan ® resin (Hatfield, UK). Phytoliths were analyzed through optical microscopy (×160 and ×640), identified with reference to literature [38][39][40] and named according to the International Code of Phytolith Nomenclature [41].…”