ORCHID SPECIES CULTURE
Charles and Margaret Baker

Psychopsis versteegiana (Pulle) Lückel & Braem

AKA: Oncidium versteegianum Pulle.

ORIGIN/HABITAT: Peru, Surinam, Ecuador, and Bolivia. This species was
originally discovered along the Tapanahoni River in Surinam but was never
again found in that locality. Later collections in Surinam were made near
the Curantyne River at King Frederick Williams Fall. In Bolivia, plants
were found at 1500 ft. (450 m) on old citrus trees in wet forest regions
near San Rafael in Chapare Province, which is in the northeastern section
of the Department of Cochabamba. In Peru, plants have been found near
Tingo Maria in the Department of Huanuco as well as in the Departments of
San Martin and Pasco. They generally grow on trees in wet mountain forests
at 1950-3950 ft. (600-1200 m). Habitat information for plants found in
Ecuador is not available. Bennett and Christenson (1993) state that
between 1961-1989 collections made in Ecuador, Peru, and Bolivia were
mistakenly identified as Psychopsis sanderae Rolfe.

CLIMATE: Station #84534, Tingo Maria, Peru, Lat. 9.1S , Long. 75.9W, at
2106 ft. (642 m). Temperatures are calculated for an elevation of 3950 ft.
(1200 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 14.4 14.4 15.0 15.0 15.5 15.5 15.5 15.5 15.5 15.0 14.4
DIURNAL RANGE  12.8 13.4 13.4 12.2 12.2 11.9 11.2 10.6 11.2 11.2 12.2 12.3
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations:

LIGHT: 1800-2500 fc. Plants may tolerate even brighter light if high
humidity and strong air movement are provided.

TEMPERATURES: Throughout the year, days average 79-82F (26-28C), and
nights average 57-60F (14-16C), with a diurnal range of 19-24F (11-13C).
These temperatures represent the coolest conditions under which this
species should be grown. Because of the especially large area of
distribution and the wide range in habitat elevation, plants should adapt
to conditions 4-6F (2-3C) warmer than indicated.

HUMIDITY: 75-80 % year-round.

WATER: Rainfall is very heavy throughout the year. However, other areas in
the habitat are probably not as wet as the region around Tingo Maria. In
some areas, there may even be a brief semi-dry period in autumn or winter.
However, the common description of the habitat in all collection reports
indicates heavy rainfall most of the year. Cultivated plants should be
watered often, but the roots must dry rapidly after watering, and the
medium should never get soggy or sour.

FERTILIZER: A balanced fertilizer, mixed at 1/4-1/2 recommended strength
may be applied weekly while the plant is actively growing. Many growers
use a lower-nitrogen, higher-phosphate fertilizer starting in late summer
and autumn. This helps promote better blooming the next season and slows
new growth allowing it to harden before winter.

REST PERIOD: Growing conditions should be at least as warm as indicated
and should be maintained all year. Water may be reduced somewhat in
winter, especially for plants growing in the dark, short-day conditions
common in temperate latitudes, but they should not stay 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 they are prefer to grow their plants in shallow pots or baskets using
an open, fast draining medium. The medium may contains materials that
holds some moisture, such as chopped sphagnum or perlite, but it must dry
fairly rapidly after watering. Charcoal is often added to help hold the
medium open and keep it from turning 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. This is
when the plant is best enable to become reestablished in the shortest
possible time. Our plant grows well for us in a galvanized chicken-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: These plants reportedly bloom sporadically throughout
the year both in the wild and in cultivation.

Plant and Flower Information:

PLANT SIZE AND TYPE: A clump-forming, 7-14 in. (19-35 cm), sympodial
epiphyte.

PSEUDOBULB: 1.6-2.2 in. (4.0-5.5 cm) long by about as wide. The broadly
ovate to suborbicular pseudobulbs are laterally flattened or compressed
and irregularly wrinkled with rounded edges. The sheaths that partially
cover the pseudobulbs are short-lived, thin, dry, and grow from the base.
They are about 3 in. (7.5 cm) long by 0.9 in. (2.2 cm) wide. The exposed
surfaces of each pseudobulb are dark reddish purple, but the protected
area under the sheaths is green.

LEAVES: 6-12 in. (15-30 cm) long. A single elliptic to oblong-elliptic
leaf is carried at the top of each pseudobulb. The keeled, more or less
sharply pointed blade is 1.6-3.5 in. (4-9 cm) wide and tapers to a short,
folded petiole at the base. The upper surface of each leaf is a dull
olive-green that may be mottled with an faint pale green if grown in low
light or a more conspicuous red-purple when grown in brighter light. The
underside of each leaf is red-purple mottled with green.

INFLORESCENCE: 26-43 in. (65-110 cm) long. The erect, flexuous flower
scape emerges from the base of the newest growths. The base of the
peduncle is broadly elliptic in cross section but gradually becomes
flatter so that the tip is sufficiently flattened that it has 2 relatively
sharp edges. Each internode is 2.6-4.0 in. (6.5-10.0 cm) long. The thin,
dry bracts at the base are about 1 in. (2.5 cm) long, but they are shorter
on the upper nodes.

FLOWERS: 1 at a time, 3-5 per inflorescence. Blossoms develop one at a
time, on each inflorescence. Flower spikes should not be cut when
flowering is finished because after the terminal bud dies, lateral
branches often develop, thereby producing another series of flowers. The
large, showy flowers are up to 4.5 in. (11.4 cm) long by 2.2 in. (6 cm)
wide. The erect very narrow, petals and dorsal sepal are 2.5-2.8 in.
(6.2-7.0 cm) long by only 0.3 in. (0.7-0.9 cm) wide. They are greenish
yellow with dark reddish brown markings on the lower half and usually a
solid reddish brown on the upper half, but sometimes the upper half of
these segments is partly yellow along the margins. The wide-spreading,
sickle-shaped lateral sepals are very different. They are 2.0-2.2 in.
(5.0-5.6 cm) long by 0.8-0.9 in. (2.0-2.3 cm) wide with lightly
crisped-undulate margins. They are bright yellow or greenish yellow
heavily marked with brownish orange transverse bars or blotches. The
3-lobed, fiddle-shaped lip is 2.0-2.4.in. (5-6 cm) long overall, and the
wide-spreading midlobe is about 1.6 in. (4 cm) long by almost 2 in. (5 cm)
wide. The lip is bright yellow with a variable amount of brownish orange
on the sidelobes and on the margin of the midlobe. These brownish orange
markings may vary from light blotching to solid, and the amount on the
margin of the midlobe may vary from a wide, irregular band to a narrow
one. The margin of the midlobe, which is very wavy, is deeply notched at
the apex. The elongated callus, which is pale yellowish white with pale
brown markings, lies between the lateral lobes and extends a little past
their center. It has 2 thick, keeled ridges that are separated by a stout,
subcylindrical, bluntly tipped center section. The stout column is green
and red-brown with a pale cream anther. The flattened wing on each side of
the column has narrow, comblike, parallel projections with the lowest
tooth or division is elliptic in shape and much broader.

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.

Dodson, C., and R. Vásquez Ch. 1982. Orchids of Bolivia, Fasc. 6, plates
501-600. Icones Plantarium Tropicarum . Marie Selby Botanical Gardens,
Sarasota, Fla.

Kennedy, G. 1977. The section Glanduligera of the genus Oncidium. Orchid
Digest 41(4):139-141.

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 94436923

.........................................................................
Please remember that this sheet is for your use only, and though it was
provided free of charge, it may not be reproduced or retransmitted in
any way without permission.
.........................................................................

__________________________________________________________________________
 "Orchid Species Culture" Charles & Margaret Baker, Portland, Oregon USA

    Orchid Culture & Pollination site    http://www.orchidculture.com
                     
                   email <cobaker@troymeyers.com>
__________________________________________________________________________

    "Orchid Species Culture Vol. 1 - Pescatorea, Phaius, Phalaenopsis,
   Pholidota, Phragmipedium, Pleione"  250 pages of culture information.

            "Orchid Species Culture Vol. 2 - Dendrobium"
  850 pages of culture information for more than 1230 Dendrobium species.

  "The genus Paphiopedilum--Natural History and Cultivation" - Part 1
    Dr. Guido Braem, Charles and Margaret Baker  ISBN 0-9665337-0-4
             Full page color photograph of each species.

  "The genus Paphiopedilum--Natural History and Cultivation" - Part 2
    Dr. Guido Braem, Charles and Margaret Baker  ISBN 0-9665337-1-2
             Full page color photograph of each species.

     "Orchid Species Culture Vol. 3 - The Laelia/Cattleya Alliance"
                       coming in a few months.
__________________________________________________________________________