The following article was written for the Orchid Species Bulletin published by the Orchid Species Society, which is based in Brisbane, Queensland in December 2006.
Bear in mind that any cultivation notes refer to the sub-tropical conditions of Southern Queensland, Australia.
Bulbophyllum
maximum (Lindl.)
Rchb.f. was first described by John
Lindley as Megaclinium maximum in 1830
in his Genera and Species of Orchidaceous
Plants. Heinrich Gustav
Reichenbach transferred it to Bulbophyllum in 1861 in Walpers,
Annales Botanices Systematicae. Being
such a large genus, there seems to be a move to resurrect the genus Megaclinium,
for those species with a prominent, usually flattened rachis. Recent authors such as Jaap Vermeulen (1987) and Victor Summerhayes have
preferred to maintain Megaclinium as a
section of Bulbophyllum. This species has been available from some nurseries as Bulbophyllum
sp. (
The
pseudobulbs of Bulb. maximum are borne
at 2-10 cm intervals along a woody rhizome that is 3-11 mm in diameter. Pale green to yellowish green, the ovoid pseudobulbs are 3-5 angled,
slightly flattened and are 3.5-10 cm long and 1-3 cm across. Occasionally the edges have large knobs as seen in plants from the
southern savannah. Each pseudobulb
has two, sometimes three, apical linear-lanceolate leaves that are thick,
leathery and pale green. The
leaves are 4-20cm long and 1.5-5.5 cm across with rounded to obtuse apices.
Inflorescences
that are 15-20 cm long are produced from the base of the matured pseudobulbs.
The peduncle has 5-14 tubular scales along the length. Often blade-like, the rachis of Bulb.
maximum is flattened and is 6-56 cm long and 8-50 mm broad. The edges of the rachis are sharp and straight to
undulate. Sometimes the rachis may be slightly twisted. Pale yellow to greenish yellow, the rachis is often spotted with purple.
It may be entirely purple or purplish-brown with fine, pale yellow spots.
From 16-120 flowers are borne along the rachis in two ranks, along the
mid-line at 2.5-9 mm intervals. Sometimes
the flowers are open simultaneously but usually they open successively so that
only a few are open at a time on each side of the rachis. Often the flowers are secund (face one direction), facing upwards.
The
flowers of Bulb. maximum are tiny and
have yellowish or greenish sepals with bright yellow tips. Often they have purple or brownish spots or
stains. They may be entirely purple or brownish with pale yellow spots. Its petals are yellowish, often with purple or brownish stains or
spots. The cream or yellowish lip is finely spotted purple. Its column is greenish and may be stained purple.
Bulb.
maximum is found over a wide area of distribution
and in many different habitats. It
has been found in lowland primary and secondary forest, montane forest, savannah
woodland from sea level to 1,500 m elevation. Growing with lichens in the central part of the crown of trees as an
epiphyte, Bulb. maximum can also be
found growing as a lithophyte on humus covered rocks. Its distribution extends from