ORCHID SPECIES CULTURE
Charles and Margaret Baker

Oncidium trulliferum Lindley

AKA: Oncidium dimorphum Regel, Oncidium galeatum Scheidweiler, Oncidium
longibulbon Mutel, Oncidium ornithocephaloides Kränzlin, Oncidium
rhynchophorum Schlechter ex Hoehne. The McQueens (1993) also include
Oncidium venustum Morren as a synonym. 

ORIGIN/HABITAT: Brazil. Plants are found both in the cooler mountains and
warm lowlands in the states of Espírito Santo, Rio de Janeiro, São Paulo,
Paraná, Santa Catarina, and possibly Rio Grande do Sul. We have been
unable to locate reports of habitat elevation, but the McQueens (1993)
report that cultivated plants "require a relatively humid, intermediate to
warm environment with good ventilation and bright indirect light to
semi-shade." We have estimated habitat elevation based on this report, but
growers should use the resulting table and cultural suggestions somewhat
cautiously. 

CLIMATE: Station #83781, Sao Paulo, Brazil, Lat. 23.6S, Long. 46.7W, at
2628 ft. (800 m). The record high is 100F (38C), and the record low is 32F
(0C). 

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX        66   67   67   68   72   75   77   79   76   73   68   66
F AVG MIN        53   53   55   57   59   62   63   64   62   59   54   54
DIURNAL RANGE    13   14   12   11   13   13   14   15   14   14   14   12
RAIN/INCHES     1.5  2.1  3.5  4.6  6.0  9.4  8.8  7.8  6.1  2.3  3.0  2.4
HUMIDITY/%       75   73   77   78   80   80   82   83   81   82   80   79
BLOOM SEASON                *    *         *         *    *    *    *    *
DAYS CLR @ 9AM    5    7    3    4    4    5    3    1    2    2    1    2
RAIN/MM          38   53   89  117  152  239  224  198  155   58   76   61
C AVG MAX      18.9 19.4 19.4 20.0 22.2 23.9 25.0 26.1 24.4 22.8 20.0 18.9
C AVG MIN      11.7 11.7 12.8 13.9 15.0 16.7 17.2 17.8 16.7 15.0 12.2 12.2
DIURNAL RANGE   7.2  7.7  6.6  6.1  7.2  7.2  7.8  8.3  7.7  7.8  7.8  6.7
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations: 

LIGHT: 2000-3000 fc. Growers report that plants adapt to both bright
indirect light and semi-shade. Direct sun should probably be avoided.
Strong air movement should be provided at all times. 

TEMPERATURES: Summer days average 75-79F (24-26C), and nights average
62-64F (17-18C), with a diurnal range of 13-15F (7-8C). Temperatures in
the preceding table represent the coolest conditions under which this
species should be grown. Because of the range in distribution and habitat
elevation, plants should adapt to conditions as much as 8-10F (4-6C)
warmer than indicated. 

HUMIDITY: 80-85% most of the year, dropping to 70-75% in winter. 

WATER: Rainfall is moderate to heavy from late spring into autumn but
decreases considerably from late autumn to early spring. Cultivated plants
should be watered heavily and often while actively growing, but drainage
should be excellent and conditions around the roots should never be
allowed to become stale or soggy. Water should be reduced after new
growths mature in late autumn. 

FERTILIZER: 1/4-1/2 recommended strength, applied weekly when plants are
actively growing. Many growers prefer to use a balanced fertilizer
throughout the year; but others use a high-nitrogen fertilizer from spring
to midsummer, then switch to one high in phosphates in late summer and
autumn.

REST PERIOD: Winter days average 66-67F (19C), and nights average 53-54F
(12C), with a diurnal range of 12-14F (7-8C). Again, plants should adapt
to conditions 8-10F (4-6C) warmer than indicated. In the habitat, rainfall
is lower in winter, but additional moisture is usually available from
heavy dew and late-night mist. Water should be reduced considerably for
cultivated plants, but they should never be allowed remain completely dry
for very long. Plants grown under cooler conditions should be given less
water than those grown with warmer temperatures. Fertilizer should be
reduced or eliminated until new growth starts and heavier watering is
resumed in spring. 

GROWING MEDIA: Mounts or small pots with excellent drainage are most
conducive to a healthy plant. They may mounted tightly to a cork or
tree-fern slab. If mounted, however, high humidity must be maintained and
plants misted at least once daily in summer. Several mistings a day may be
necessary during extremely hot, dry weather. Growers report that plants
also grow well in small pots with excellent drainage. The medium should be
coarse and fast-draining to allow the roots to dry rapidly after watering.
Most growers recommend tree-fern chunks or bark. Plants can not tolerate
stale conditions around the roots, so the medium must be replaced before
it breaks down. They are best repotted when new root growth is just
starting. This allows the plant to become established in the shortest
possible time with the least amount of stress. 

MISCELLANEOUS NOTES: The bloom season shown in the climate table is based
on cultivation records. 

Plant and Flower Information:

PLANT SIZE AND TYPE: A relatively large epiphyte 15 in. (38 cm) tall. 

PSEUDOBULB: 4-8 in. (10-21 cm) long by 1 in. (2.5 cm) wide. The dull-green
pseudobulbs are more or less oblong, somewhat compressed, with several
thin, papery sheaths at the base. 

LEAVES: 6-9 in. (15-23 cm) long by 1-2 in. (2.5-5.0 cm) wide. The apex of
each pseudobulb carries 2-3 somewhat erect to spreading leaves. They are
oblong to lanceolate with a pointed tip and a narrow folded base. 

INFLORESCENCE: 24 in. (60 cm) long. The gracefully arching inflorescence,
which produces many branches upper portion, emerges from the base of
recently matured pseudobulbs. 

FLOWERS: 50-100. The long lasting blossoms are about 1 in. (2.5 cm) across
with bright yellow to greenish yellow sepals and petals marked with
red-brown bars and a yellow lip which is red in front of and on the
callus. The concave dorsal sepal is about 0.3 in.(0.8 cm) long and held
hoodlike over the column. Spoon-shaped lateral sepals, which are joined at
the base, are about 0.5 in. (1.2 cm) long by 0.2 in. (0.4 cm) wide and
widely spread. The almost rectangular, widely spread petals are about 0.4
in. (1 cm) long by 0.3 in. (0.7 cm) wide with wavy, irregular margins. The
3-lobed lip is 0.6 in. (1.5 cm) long has rounded, earlike sidelobes and a
round, widely spread apical lobe is vaguely bilobed and wavy along the
margin. The callus has 3 very warty lobes. The one in front is
saddle-shaped, and the two in the rear are spreading. The column is
curved, almost s-shaped, and the elongated anther and rostellum together
produce a beaklike projection near the apex of the column. This projection
is much like the allied Oncidium ornithorhyncum Humboldt, Bonpland, &
Kunth from Mexico and Central America. One cultivated variety has pale
glossy green sepals and petals with no red markings, a fleshy lip that is
very pale yellow to almost white with yellow on the large callus, and a
nearly white column with spreading, narrowly oblong wings near its apex. 

HYBRIDIZING NOTES: N/A. 

REFERENCES: 

Cogniaux, A. 1893-1906. Martii, Flora Brasiliensis-Orchidaceae III, vol.
III, part 6. 

Hamilton, R. 1988. When does it flower? 2nd ed. Robert M. Hamilton, 9211
Beckwith Road, Richmond, B. C., Canada V6X 1V7.

McQueen, J., and B. McQueen. 1993. Orchids of Brazil. Timber Press,
Portland, OR. 

Pabst, G., and F. Dungs. 1975. Orchidaceae Brazilienses, book 1 and 2.
Brücke-Verkag Kurt Schmersow, Hildesheim, Germany


Copyright 1997, Charles O. Baker and Margaret L. Baker
Sheet version 9279

.........................................................................
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.
__________________________________________________________________________