Bifrenaria - Distribution and Habitat

Distribution and Habitat

Bifrenaria exist from the north of South America, one species reaching Trinidad, until Rio Grande do Sul, the farther south State in Brazil, however they are split in two isolated areas: Amazon Forest and Atlantic Forest of Brazil. The later, where seventeen species are present, may be considered their recente center of distribution. The montane area of Rio de Janeiro State and Espírito Santo is particularly rich with fifteen species registered. Serra dos Órgãos mountains area, in Rio, is reported as habitat of fourteen Bifrenaria species, however, some of these species are considered synonyms today, being eleven a more realistic number of species existing in the said area.

The species with large flowers are more common on Region Southeast of Brazil, however, they inhabit from the sunnier areas of the seashore to rocky mountain areas of Minas Gerais e Bahia States, from almost sea level up to 2,000 meters of altitude, some species reaching Rio Grande do Sul state. No species of large flowers exist in Amazon Forest. Some species grow directly attached to the famous Sugarloaf Mountain in Rio de Janeiro which can be observed by the commuters in the cable car. The recent centers of irradiation of this group are the seashore close to Serra do Mar chain of mountains, and the high chains of mountains of Minas Gerais. The most common species in this group, spread from Rio Grande do Sul to Bahia, is B. harrisoniae.

The smaller species of Bifrenaria, which some taxonomists classify under the genus Adipe, are more common on less sunny areas and can be found between 300 and about 1,600 meters of altitude. Six species are native in Serra do Mar Chain of mountains and its arms, place considered the center of distribution of the small species. Only three small species inhabit Amazon, B. longicornis, which is more common at low artitudes; Bifrenaria venezuelana, up to 1,450 meter of altitude, and B. steyermarkii from even higher altitudes, in Roraima State, in Brasil, and nearby areas in Venezuela and Surinam.

The most common species is B. aureofulva, however, because the geographic characteristic of its territory, without obstacles, B. longicornis is the species spread throughout the largest area, reaching Colombia, Venezuela, Peru, Surinam, Guyanas, Trinidad and all Amazonic area in Brazil. Two species seem to be endemic in highly restricted areas: B. silvana. discovered in 1987 at Serra da Ouricana mountains, nearby Itororó, in Bahia whch belongs to Adipe group; and B. verboonenii, discovered in September 1995 on Serra do Cipó mountains, close to Diamantina, Minas Gerais, of the large Bifrenara group.

Bifrenaria species inhabit three different environments. The large species generally live in well illuminated areas, occasionally epiphyte on trees of sparse foliage, more often as lithophytes, in campos rupestres, montane rocky areas that exist mostly in Rio and Minas Gerais States of Brazil, or over rocks in jungle's clearances. B. tyrianthina is exclusively lithophyte, B. tetragona and B. wittigii hardly ever do. B. atropurpurea is the only species found living terrestrially, but in rare occasions. The large species always show .

The small species from Southeast Brazil live in cloud montane forests, where the appear in much darker places than the large species. Within this sort of forests the temperature presents noticeable difference between day and night and also through the seasons. These also are plants of caespitous growth, almost all epiphytes, despite there is at least one record of Bifrenaria aureofulva living lithophylically in Chapada Diamantina, Bahia.

The species from Amazon inhabit tropical lowland forests and equatorial forests. Bifrenaria longicornis is mostly found in flood areas along the igapós and igarapés (seasonal flood streams and small rivers of Amazon), and occasionally in open fields where the humidity is high and temperature constant through the year, normally in well illuminated places, although not under direct sunlight. B. venezuelana inhabits forests in higher elevations, closer to the Andes. Amazon species are epiphyte and the only Bifrenaria species with elongated rhyzome and ascendant growth.