Polystachya concreta and Cadetia microphyton
The two species we are discussing today have the distinction of: One being widespread, throughout much of the world, whilst the other is locally endemic or found nowhere else but the Philippines.
The genus Polystachya was created by the great English botanist/taxonomist Sir William J. Hooker in 1824, in his
Exotic Flora. There are more than two hundred and twenty-four species in the genus, which is extremely widespread, and species of this genus have been recorded from Guinea to Zimbabwe in tropical Africa, Madagascar, the Reunion Islands, and the Seychelles; other species are known to occur in the state of Florida in the United States of America, Cuba, Hispaniola, Mexico, Brazil to northern Argentina. The genus is also recorded from Thailand, Vietnam, Indonesia, and the Philippines. This genus probably has the widest distribution, apart from Bulbophyllum, of any epiphytic genera. The generic name refers to the branched inflorescence, which in some species may resemble the spikes of a head of wheat. Flowers are usually non-resupinate (with the labellum uppermost.) Polystachya concreta has the distinction of being the most widely distributed of any epiphytic orchid species known to us. Apart from the countries mentioned above, Polystachya concreta has been found in Sri Lanka, north east India, China, the Nicobar Islands, Laos, Kampuchea (Cambodia), Peninsular Malaysia, Borneo, and Sulawesi. In the Philippines, it is known from the provinces of Benguet, Bulacan, the Mountain Province, Nueva Ecija, Nueva Vizcaya, Pangasinan, Quezon Province, Rizal, and Zambales on Luzon; the islands of Biliran, Bohol, and Leyte in the Visayan Sea; and the provinces of Bukidnon and Lanao on Mindanao. It grows as an epiphyte, and occasionally on rocks, at elevations of up to 1,200 meters. Aging flowers undergo a color change from green to orange.
One can only wonder whether a species such as Polystachya concreta, with such a world-wide distribution, can really be the same species throughout its multitude of habitats. We hasten to add, that the plants studied by the authors, have shown very little variation, throughout their range in the Philippines. It’s also ironic, that despite the vast distribution here, it remains a rather rare orchid in the wild and more so in cultivation.
The genus Cadetia was created by the French botanist Charles Gaudichaud-Beaupré in 1826. The generic name honours Louis Claude Cadet de Gassicourt, a French lawyer, chemist, and the author of a dictionary on chemical terms. This is another genus, which has been transferred between being either a section or a genus in the
Dendrobium. We prefer to maintain it as a genus.
Plants from this genus are most common on the large, mountainous island of New Guinea, which is also their centre of distribution, with about sixty different species. Other members of the genus are found in the Solomon Islands, northern Australia, New Caledonia, and a single species being recorded from the Philippines. Cadetia microphyton, was first described by the American botanist Louis O. Williams, in 1937 as a member
of the genus Dendrobium in 1937. Dr. Eric Christenson transferred it to the genus Cadetia in 1992, in the scientific journal of the American Orchid Society, Lindleyana.
Members of the genus Cadetia can be easily recognised by their single-node pseudobulb, which carries a single leathery leaf. Plants can easily be mistaken as a member of the genus
Bulbophyllum. The single flower appears from the junction of the pseudobulb and the leaf. The small flowers are milky white and last in good condition for several weeks.
In the Philippines, this species is only known from the Visayan island of Bohol; and the province of Bukidnon on Mindanao. It is probably more widely spread on Mindanao, but escapes detection because of its small size. It grows both on trees and rocks at elevations of between 300 and 1,000 meters.