ORCHID SPECIES CULTURE
Charles and Margaret Baker

Psychopsis sanderae (Rolfe) E. Lückel & G. J. Braem

AKA: Oncidium sanderae Rolfe. During the years 1961-1989, plants collected
in Ecuador, Peru, and Bolivia that were actually Psychosis versteegianum
were misidentified as Psychopsis sanderae. As a result, there are
undoubtedly many plants of Psychosis versteegianum that are mislabeled as
Psychopsis sanderae. The true Psychopsis sanderae was rediscovered in
1989, but we were told that the site where the plants were found has now
been destroyed as orchid habitat.

ORIGIN/HABITAT: Peru. These plants were rediscovered in the Department of
Junin, but the exact locality and elevation were not reported. They were
growing high up the trunks of trees and on large branches in wet mountain
forests. Habitat elevation was not reported, so we have estimated it at
4000 ft. (1220 m) based on reports from others. Consequently, growers
should use the temperatures indicated in the following table and resulting
Cultural Recommendations cautiously.

CLIMATE: Station #84534, Tingo Maria, Peru, Lat. 9.1S , Long. 75.9W, at
2106 ft. (642 m). Temperatures are calculated for an estimated elevation
of 4000 ft. (1220 m), resulting in probable extremes of 91F (33C) and 33F
(1C).

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX        80   82   82   81   81   81   80   79   80   80   81   80
F AVG MIN        57   58   58   59   59   60   60   60   60   60   59   58
DIURNAL RANGE    23   24   24   22   22   21   20   19   20   20   22   22
RAIN/INCHES     5.8  8.2  8.0 15.9 24.9 12.0 15.9 16.4 22.8  8.5  8.7  4.5
HUMIDITY/%       78   76   77   79   78   80   81   81   81   80   78   79
BLOOM SEASON    N/A
DAYS CLR @  7AM   2    3    3    1    1    1    0    0    0    1    1    1
DAYS CLR @  1PM  15   12    9    3    4    4    4    1    4    2    7   12
RAIN/MM         147  208  203  404  632  305  404  417  579  216  221  114
C AVG MAX      26.7 27.8 27.8 27.2 27.2 27.4 26.7 26.1 26.7 26.7 27.2 26.7
C AVG MIN      13.9 14.3 14.3 14.9 14.9 15.4 15.4 15.4 15.4 15.4 14.9 14.3
DIURNAL RANGE  12.8 13.5 13.5 12.3 12.3 12.0 11.3 10.7 11.3 11.3 12.3 12.4
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations:

LIGHT: 1800-2500 fc. Plants may tolerate higher light if humidity is high
and air movement is brisk.

TEMPERATURES: Throughout the year, days average 79-82F (26-28C), and
nights average 57-60F (14-15C), with a diurnal range of 19-24F (11-14C).
The warmest days, coolest nights, and greatest diurnal range occur in late
winter.

HUMIDITY: 75-80 % year-round.

WATER: Rainfall is very heavy throughout the year. Conditions in specific
habitat may not be as wet as the region around Tingo Maria. Cultivated
plants should be watered often, but the roots must dry rapidly after
watering, and the medium should never become soggy and sour.

FERTILIZER: 1/4-1/2 recommended strength, applied weekly during periods of
active growth. Many growers recommend using a balanced fertilizer all
year. If plants are being grown in the higher latitudes where light may be
low or temperatures might be cool, fertilizer should be reduced anytime
the plants are not actively growing to prevent a salt buildup in the
medium.

REST PERIOD: Growing conditions should be maintained all year. Growers are
reminded that the temperatures indicated in the climate table are based on
estimated habitat elevation and should be used with caution. Water may be
reduced somewhat in winter, especially for plants grown in the dark,
short-day conditions common in temperate latitudes. They should not dry
out or be dry for long periods. If water is reduced, fertilizer should
also be reduced until water is increased in spring.

GROWING MEDIA: Plants may be mounted on tree-fern or cork slabs if
humidity is high and plants are watered at least once daily in summer.
Mounted plants may need several waterings a day during very hot, dry
weather. Many growers have trouble keeping mounted plants moist enough,
and prefer to grow plants in shallow pots or baskets using an open, fast
draining medium which contains materials that retain some moisture, such
as chopped sphagnum or perlite, but dries fairly rapidly after watering.
Charcoal is often added to help keep the medium open and prevent it from
becoming sour. Undersized pots just large enough to hold the roots should
be used. Repotting should be done only when necessary, and then only just
as new root growth is starting so that the plant can become reestablished
in the shortest possible time. As with the other species in the genus,
these plants should grow well in a wire basket lined with coconut fiber
and then filled with a mixture of fine- and medium-grade tree-fern fiber
mixed with about 10% perlite and 10% charcoal.

MISCELLANEOUS NOTES: In the habitat, plants probably bloom sporadically
during many months of the year.

Plant and Flower Information:

PLANT SIZE AND TYPE: A clump-forming, 6-10 in. (15.5-24.5 cm) sympodial
epiphyte.

PSEUDOBULB: 1.4-1.8 in. (3.6-4.6cm) long by 1.2-1.5 in. (3.0-3.8 cm) wide.
The laterally compressed pseudobulbs are egg-shaped to elliptical in
outline. The wrinkled surfaces are normally dull purple often mixed with
dull green.

LEAVES: 5-8 in. (12-20 cm) long. A single, leathery, leaf is carried at
the top of each pseudobulb. The narrowly oblong-elliptic leaf is 1.2-1.6
in. (3-4 cm) wide, tapers to a sharp point at the tip, and tapers to a
short, folded petiole at the base. The upper surface is pale grayish
purple with dull, opaque, pale green blotches and coalesced spots. The
underside is dull purple with opaque, pale green flecks and dots.

INFLORESCENCE: 14 in. (35 cm) long. The erect, lightly flexuous peduncle,
which is broadly elliptic in cross section, emerges from the base of the
most recently matured pseudobulb. It has internodes spaced 1.5-1.7 in.
(3.8-4.4 cm) apart. Each slightly swollen node is covered by a thin, dry,
membranelike, tubular bract that is about 0.8 in. (2 cm) long. The
peduncle is dull green with a dense covering of dark brownish purple
markings that are less numerous on the upper part of the growth.

FLOWERS: 1 at a time, 2-4 per inflorescence. Each inflorescence produces
2-4 blossoms one after another. After flowering is over on the primary
spike, it often produces a lateral branch that develops from one of the
upper nodes. Flowers are 5-6. (13-15 cm) tall by about 2 in. (5 cm)
across. The tips of the petals and dorsal sepal are dark reddish brown
that shades to pale brown on the basal 1/4. Lateral sepals are bright,
clear yellow marked with comparatively small red-brown blotches. The lip
is a brilliant greenish yellow with numerous, small, sharply defined red
spots and blotches around the border of midlobe. The callus is dull white
marked with chestnut-brown. The dark purplish brown column has medium
brown fringed, comb-like wings with very dark brown glandular tips. The
anther is pale yellowish green with a dark brownish purple tip divided by
a broad yellowish green stripe. The erect petals and dorsal sepals are
about 4 in. (10 cm) long by about 0.2 in. (0.5 cm) wide, with the dorsal
sepal being slightly wider and folded as well as bent slightly to one side
at the apex. The sickle-shaped lateral sepals, which are about 2.2 in.
(5.8 cm) long by 0.6 in. (1.5 cm) wide, have strongly crisped margins. The
3-lobed lip is approximately 2 in. (5 cm) long by 0.8 in. (2 cm) across
the expanded lateral lobes by 1.8 in. (4 cm) wide across the fully open
mid-lobe. The margins of the mid-lobe are very crisped, and it is deeply
notched at the apex. The callus, which is at right angles to the column,
is broad at the base with a thick outer edge with 2 knobs. Its thick
mid-section is divided in 3 with 2 lateral subconical teeth separated by a
free apex. The stout, erect column is abruptly dilated at the apex.

HYBRIDIZING NOTES: Chromosome count is 2n = 38.

REFERENCES: .

Bennett, D. E. Jr. and E. Christenson. 1993. Icones Orchidacearum
Peruviarum. Pub. privately by A. Pastorelli de Bennett.

Braem, G. J. 1993. Studies in the Oncidiinae. Schlechteriana 4(1-2):8-29.

Index kewensis S18.

Orchidee, 33(1): 6 (1982)

Rolando, I. and E. Christenson. 1993. Peruvian Orchids. The rediscovery of
Psychopsis sanderae (Rolfe) Lückel & Braem and elucidation of Psychopsis
versteegianum (Pulle) Lückel & Braem. Orchid Digest 57(3):116-118.

Schweinfurth, C. 1958-1961. Orchids of Peru. Fieldiana: Botany 30(1-4).
Chicago Natural History Museum Press, Chicago. 

Copyright 2000, Charles O. Baker and Margaret L. Baker
Sheet version 94436922

.........................................................................
Please remember that this sheet is for your use only, and though it was
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 "Orchid Species Culture" Charles & Margaret Baker, Portland, Oregon USA

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