Vriesea oligantha An obligate Epiphyte of Velloziaceae by Claudio Coelho de Paula & Elidio Armando Exposto Guarconi in J. Brom. Soc. 55(5): 195-8. 2005
Vriesea oligantha (Baker) Mez was first described in 1884, from a specimen collected at Serra do Ouro Branco, Minas Gerais, Brazil. According to Smith & Downs (1977), this species is found in the Serra do Ouro Branco, Serra do Cipo and Serra do Capanema, in the state of Minas Gerais and usually occurs in Campos Rupestres (grasslands on rocky soils). Coffani-Nunes (1997) extended its distribution to the northeastern state of Bahia, along Cadeia do Espinhaco.
Vriesea oligantha grows between 1100 and 1400 m above sea level where it is found exclusively on species of Velloziaceae (FIGURE 1), specifically Vellozia compacta and V. dracenoides, in Serra Ouro Branco and Serra do Cipo, respectively. These Velloziaceae are known in Brazil as "canela-de-ema:" Vriesea oligantha is occasionally observed on rocks or in soil, but in such cases, this is due to a plant having fallen off of its host.Thus, Vriesea oligantha should not be classified as rupicolous or terrestrial, as cited by some authors.
Vriesea oligantha is easily recognized by its almost silver-grayish leaves with small purple color spots, arranged in the form of an urn. Other prominent characteristics of this species are the erect scape and simple inflorescences with secund flowers after anthesis, almost perpendicular to the rachis (FIGURES 4, 6).The plants can be seen from a considerable distance in the middle of the foliage of Vellozia thanks to their erect inflorescences.The flowers have light yellow petals and open at night, characteristic of section Xiphion to which it belongs (FIGURE 3). In Serra do Cipo, Vriesea oligantha blooms between November and January. The fruits are turned down when ripe, which may facilitate seed dispersion by the wind (FIGURE 5).
On Serra do Ouro Branco, Vriesea oligantha grows exclusively on old plants of Vellozia compacta, especially in the highest parts of this plant where the greatest amount of sunlight is available. A large number of young individuals that are ellipsoid in shape (FIGURE 2) are commonly observed around adult plants.
Adult individuals develop a lateral sprout soon after flowering, which originates from the bud in the axial of the most outer leaves of the rosette. In some isolated plants, a large number of small offshoots can be observed, even before flowering.
The major conservation problem facing Vriesea oligantha is the exploitation of its host, canela-de-ema, which is used as firewood and also for landscape purposes and orchid and bromeliad cultivation. The harvesting of canela-de-ema has led to the loss of many populations of V. oligantha.
Vriesea oligantha is included in the "List of presumably endangered species in Minas Gerais flora" (Mendonca & Lins, 2000). The preservation of this species depends mainly on the conservation of its natural habitats, especially by protecting the "canelas-de-ema". —SeeSmith & Downs 1977
