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The following article was written
for the Orchid Species Bulletin published by the Orchid
Species Society, which is based in Brisbane,
Queensland in July 2009.
Bear in mind that any cultivation notes refer to the sub-tropical conditions of Southern Queensland, Australia.
Spathoglottis
affinis de Vriese is
perhaps better known under the synonym of Spa.
lobbii Rchb.f. as it was labelled at the June meeting. Gunnar
Seidenfaden (1986) realised that the flowers of Spa.
lobbii from
Thailand
have a longer and narrower claw at the base of the lip,
otherwise they are identical to Spa.
affinis. Hugo de Vriese described Spa.
affinis in Illustrationes
Orchidacearum Indiae Orientalis in 1855. The specific epithet comes from the
Latin affinis (neighbouring, allied
to).
Spa.
affinis is a terrestrial or lithophytic plant. The
pseudobulbs are found below the ground and are flattened and of irregular shape.
Each pseudobulb bears 2-4 linear-lanceolate apical leaves that are up to 30 cm
long and 2-3 cm wide. The pleated leaves are deciduous and are often not on the
plant during the flowering period. Finely hairy inflorescences are produced from
nodes at the base of the leaf that are usually much longer than the leaves.
The
upright inflorescences of Spa. affinis
are about 20-30 (-70) cm tall and bear about 15 well-spaced flowers that open
progressively. Usually there are 4-6 blooms open towards the apex of the raceme
at any one time. The blooms are arranged around the rachis to face in all
directions. About 2.5-3 cm across, the bright yellow to sulphur-yellow flowers
have the lateral sepals sometimes faintly streaked or veined with red. The short
rounded fleshy, twin knob-like calli at the base of the lip are mottled red to
purple.
A widespread species, Spa. affinis is
distributed from Vietnam, Laos, Burma, Thailand, Peninsular Malaysia to Java and possibly
Borneo. It grows in open rocky habitats at elevations between
600-1,000 m. Spa. affinis is a species
adapted to a seasonal climate, with only the underground pseudobulbs surviving
through the dry season. In cultivation this dry rest must be observed for very
little water is needed when the plant is leafless.
Spa.
affinis requires 50-70% shade, a
well-drained medium and good air circulation. Water regularly while it is
actively growing to keep the potting medium evenly moist and maintain high
humidity. Watering frequency should be reduced after the leaves have been shed.
After flowering has finished, very occasional misting or water can be given to
prevent the pseudobulb from excessive shrivelling. Repot annually as new growth
commences.
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