Disperis
is a large genus centred in Africa and also ranges into Asia with a few
species (India, Thailand, Phillipines, New Guinea). 26 species are found
in both rainfall regions in South Africa. Disperis species are slender
plants with small to medium-sized flowers and are thus not very conspicuous
despite of their sometimes brilliant colours. The plants grow singly or
in small groups and are to be found in forest, scrub and grassland. The
pollination of Disperis is interesting, and is carried out mainly
by specialized bees that collect oil. Flowering is mainly in spring and
summer.
The plants are terrestrial with underground root tubers and are 10-50
cm tall. The one to five leaves are mostly cauline (borne on the stem).
In case of two leaves these may be alternate or opposite. Inflorescences
are rather laxly one- to few-flowered. The small or medium-sized flowers
are white, cream, yellow, green or magenta. Their median sepal is usually
hooded, but rarely extended into a prominent spur. A remarkable feature
of this genus is the spurred lateral sepals. Basally fused to the column,
the lip is very variable in shape and has an appendage that may be larger
than the lip itself. The column is very complicated, with parts sticking
forward (the lateral rostellum arms).
Selected species and their main distribution
Winter-rainfall area: D. villosa ('moederkappie', 'oumakappie'),
D. bolusiana, D. cucullata ('witch orchid', 'moederkappie'), D.
capensis ('horing moederkappie', 'mombakkiesblom'), D. circumflexa
Summer-rainfall area: D. anthoceros, D. micrantha, D. lindleyana
('granny bonnet'), D. cardiophora, D. stenoplectron, D. tysonii ('witch
orchid'), D. fanniniae ('bonnet orchid')
Both areas: D. paludosa ('moederkappie')
Cultivation
The cultivation of plants of this genus is difficult and therefore seldom
attempted.
Winter rainfall species
Some Disperis species are from the winter-rainfall
region of South Africa and instructions for growing satyriums can be followed.
The plants should be planted in a well drained medium in a deep pot (20
- 30 cm deep). A suitable medium would consist of 70 % river sand and
30 % milled pine bark or well-decomposed compost. Decomposed pine needles
are also beneficial. If the river sand is fine and compacts too much,
20 % Polystyrene granules or some other inert medium should be added to
the river sand to improve aeration. Additionally some compost or leaf
mould can be placed in the base of the pot and the rest of the medium
on top.
Pots can be kept under 40 % shade. For species from the
winter-rainfall region plants should be watered regularly from the time
that temperatures start dropping in autumn until mid spring. Gradually
increase the intervals between watering until in midsummer (November till
end of February), when watering should stop. This is a crucial dormancy
period for the plants, over-watering during this period will cause the
tubers to rot. The pots should be kept cool and damp enough so as not
to dehydrate completely, i.e. not reach permanent wilting point. A handy
way of keeping the medium at the available water capacity level is to
grow a non-invasive hardy herbaceous indicator plant in the same pot.
The indicator plant can be weeded out when the disperis starts to re-grow
at the beginning of the new growth season. In the case of disperis, a
summer annual would be suitable. As soon as it appears to start wilting,
drench the pot. Plunging the pots and placing a mulch of bark nuggets,
wood chips, straw or pine needles on top will aid in keeping the tubers
cool and prevent excessive dehydration of the medium.
Summer rainfall species
Disperis species from the summer-rainfall region
can be cultivated in the same manner as summer- rainfall region species
of eulophias. Plants should be planted in a well drained medium in a deep
pot under 40 % shade. A suitable medium would be 70 % river sand and 30
% milled pine bark or well-decomposed compost. Additionally some compost
or leaf mould can be placed in the base of the pot and the rest of the
medium on top. Most of the cultivated disperis from summer rainfall areas
are dormant during the winter period. The plants should thus be treated
like bulbs and kept on the drier side during the winter season, commencing
with watering only once the new shoots appear. Watering in the summer
period can be done once or twice a week, depending on dehydration rate
of the medium. Feeding is only done during the summer growth season. Fertilisers
that have been used successfully are: Nutrisol, Nitrisol, Seagro, Multifeed
10, Osmocote and Horticote.
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