Bulbophyllum section Sestochilus
In the family Orchidaceae the genus Bulbophyllum reigns supreme in having the most species, with estimates of more than 2,000 species, being regularly stated. Many new species are still being described on a regular basis in this fascinating genus, with a seemingly endless array of diversity, floral forms and variations. One would suspect as more DNA studies are done on the genus Bulbophyllum, there will be major changes, with a good number of new genera either being created, or old genera being resurrected. As with any large genus, the members are arranged into sections of similar, or related species. Today’s article is about one of these sections.
Section Sestochilus is characterised by having single-flowered inflorescences, with a large bloom. The plants could also be considered to be large.
Bulbophyllum lobbii is one of the more widely distributed species in the section and it has been recorded from Myanmar, Thailand, Peninsular Malaysia, throughout the islands of Indonesia, to Borneo, Sulawesi, Maluku, and New Guinea. As could be expected from such a widely distributed species, there is much variation in the size of the flowers and the plants, and numerous varietal and forma epithets have been applied to this species. The species illustrated here is from the mountains of central Luzon and has a flower about 17.5 cm tall, a particularly lovely feature of this species is that the tip of the labellum is almost black with a bright yellow apex.
Bulbophyllum lobbii subsp. brevifolium is also widely distributed and is known from Thailand, Peninsular Malaysia, Sumatra and Borneo. In the Philippines, this species is only known from Palawan and is well known as Bulbophyllum palawanense, but this epithet has never been validly published so should not be used. The flowers of this subspecies are about 8 cm tall.
Bulbophyllum dearei is also found in a number of countries, and is also known from Peninsular Malaysia and Borneo. In the Philippines, it is known from some of the islands in the Visayan Sea and Mindanao. There is great variation in the size of the plants and flowers of this species in the Philippines. This is a most difficult species to photograph satisfactorily, because of the reflexed petals and the hooded dorsal sepal over the column, making a decent front-on image almost impossible to achieve. Still these characters do not distract from the unique beauty of this magnificent species.
Bulbophyllum apheles, until recently was thought to be endemic to Sabah on Borneo, but it has recently been discovered on the island of Mindanao, by members of the Cootes Study Group. The Philippine plant is from high elevations, but not as high as those of the Bornean plant. The flowers are quite small at about 3 cm across the lateral sepals.
Bulbophyllum piestoglossum is endemic to the Philippines and is only known from the mountains of southern Luzon, where it grows at elevations of between 600 and 1,300 metres. It is quite a spectacular species with its wide floral segments and large blooms, which are about 6 to 8 cm tall.
Bulbophyllum santosii is a stunning species that differs from all the other species mentioned here in having a two to three flowered inflorescence. It also differs in having milky-white flowers about 3 to 4 cm in diameter. This species is probably the most widely distributed species of section Sestochilus in the Philippines. It is known from throughout the whole of the Philippine archipelago, and amazingly, for such a widely distributed species, there appears to be little variation in the size of the plant or color of the flowers.