Friday 1 June 2012

New species of Bromiliad from Brazil.

Bromeliads are monocotyledonous plants related to grasses. They are a diverse group, including many epiphytes (plants that grow on other plants, typically on the branches of trees), and a number of fleshy, succulent species dwelling in deserts. Bromiliads are noted for their tight whorls of leaves, that sometimes trap pools of water at the base. The group are almost entirely restricted to the American tropics, with a few subtropical species, and a single known species native to West Africa.

In a paper published in the journal Phytotaxa on 11 September 2011, Rafael Batista Louzada of the Departamento de Botânica at the Instituto de Biociências at Universidade de São Paulo and the Instituto de Botânica at the Secretaria do Meio Ambiente, and Maria das Graças Lapa Wanderley, also of the Instituto de Botânica at the Secretaria do Meio Ambiente, describe a new species of Bromeliad from the Chapada Diamantina National Park in Bahia State, Brazil.

The new species is placed in the genus Orthophytum, Straight or Erect Bromiliads (so called because of their erect flower spikes) and given the specific name argentum, meaning silver, the leaves having a silvery sheen. It is a 24-34 cm plant, topped by an 11-18 cm flower spike, growing on quartzite rock outcrops between 1000 and 1300 m in altitude; its closest relatives are forest dwellers.

Orthophytum argentium. (A) Whole plant. (B) Complete flower with floral bract. (C) Floral bract. (D) Abaxial sepal. (E) Adaxial sepal. (F) Adaxial sepal with the opposite stamen. (G) Petal with one adnate stamen, showing two petal callosities and two supra basal appendages. (H) Flower section showing adaxial sepal with the opposite stamen, petal with the adnate stamen, petal callosities and appedages, and the gynoecium showing style, stigma and ovary with axial placentation. (I) Detail of the stigma. Louzada & Wanderley (2011).

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