ORCHID SPECIES CULTURE
Charles and Margaret Baker

Chysis aurea Lindley

AKA: Plants of the genus Chysis, while widespread, are rather uncommon.
There has been and continues to be considerable confusion regarding the
status of several species. Some authorities consider Chysis aurea and
Chysis laevis to be synonymous and have listed these plants as Chysis
aurea with distribution from Mexico, through Central America, to
Venezuela, Colombia and Peru. Most authorities now, however, seem to
consider plants from Mexico and northern Central America to be Chysis
laevis, while plants from South America are considered to be Chysis aurea.
Although very similar, the flowers of C. laevis are reportedly larger,
have slight differences in the keels on the lip, and are somewhat
differently colored than those of those of C. aurea. 

ORIGIN/HABITAT: Venezuela, Colombia, and possibly northward into Panama.
Variety maculata is reported as far north as Costa Rica. Plants are
normally found at lower elevations in dense, moist forests where they grow
high up in tall trees, mainly on the trunks or the basal part of large
branches. In Venezuela, plants were found near Caracas at about 2500 ft.
(760 m) in a damp section of forest near a ravine with running water. 

CLIMATE: Station #80416, Caracas, Venezuela, Lat. 10.5N, Long. 66.8W, at
2760 ft. (841 m). Temperatures are calculated for an elevation of 2500 ft.
(760 m), resulting in probable extremes of 92F (33C) and 46F (8C). 

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX        76   78   80   82   81   79   79   80   81   80   78   79
F AVG MIN        57   57   59   61   63   63   62   62   62   62   61   59
DIURNAL RANGE    19   21   21   21   18   16   17   18   19   18   17   20
RAIN/INCHES     0.9  0.4  0.6  1.3  3.1  4.0  4.3  4.3  4.2  4.3  3.7  1.8
HUMIDITY/%       77   74   73   74   80   80   80   79   79   81   83   81
BLOOM SEASON      *    *    *   **   **    *   **    *         *
DAYS CLR        N/A
RAIN/MM          23   10   15   33   79  102  109  109  107  109   94   46
C AVG MAX      24.4 25.6 26.7 27.8 27.2 26.3 26.2 26.7 27.2 26.7 25.6 26.1
C AVG MIN      13.9 13.8 14.9 16.0 17.1 17.1 16.6 16.6 16.6 16.6 16.0 14.9
DIURNAL RANGE  10.5 11.8 11.8 11.8 10.1  9.2  9.6 10.1 10.6 10.1  9.6 11.2
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations: 

LIGHT: 2500-3500 fc. Light should be somewhat filtered or diffused, and
plants should not be exposed to direct midday sun. Strong air movement
should be provided at all times. 

TEMPERATURES: Summer days average 79-80F (26-27C), and nights average
62-63F (17C), with a diurnal range of 16-18F (9-10C). 

HUMIDITY: 75-80% year-round. Conditions may be somewhat more humid in the
habitat, however. 

WATER: Rainfall is moderate to heavy from late spring into autumn. Amounts
then diminish into a 3-4 month winter dry season. Cultivated plants should
be watered heavily while actively growing, but the medium must not be
allowed to become stale or soggy. Water should be reduced in late autumn
after new growths have matured. 

FERTILIZER: 1/4-1/2 recommended strength, applied weekly. A high-nitrogen
fertilizer is beneficial from spring to midsummer, but a fertilizer high
in phosphates should be used in late summer and autumn.

REST PERIOD: Winter days average 76-79F (24-26C), and nights average
57-59F (14-15C), with a diurnal range of 19-21F (11-12C). Rainfall is low
in winter, but additional moisture is generally available during nights
and early mornings from heavy dew and mist. Water should be reduced for
cultivated plants in winter, but they should not be allowed to remain dry
for long periods. Fertilizer should be reduced or eliminated until new
growth starts and heavier watering is resumed in spring. 

GROWING MEDIA: Because of the pendent growth habit, these plants are
probably more easily managed if grown mounted on a slab of rough bark or
tree-fern fiber. Humidity must be kept high for mounted plants, however,
and they must be watered at least once daily in summer. Several waterings
a day may be necessary for mounted plants during extremely hot dry
weather. Plants also grow well in hanging pots or baskets that allow the
growths to hang naturally and are filled with an open, fast draining
medium that enables the roots to dry rapidly after watering. For plants in
pots or baskets, many growers recommend using a shredded tree-fern fiber
as a medium because it breaks down more slowly than bark and, therefore,
requires repotting less often. Some growers also recommend adding perlite
and large chunks of charcoal to the potting mix. Because these plants do
not usually respond well when disturbed, repotting or dividing should be
done only when the medium breaks down or the plant has overgrown its
container. When repotting or dividing is necessary, however, it should be
done only 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 relative large, descending to pendent sympodial
epiphyte with growths that may reach 20 in. (50 cm) long. 

PSEUDOBULB: 20 in. (50 cm) long. The spindle-shaped pseudobulbous stems
are completely enveloped by the sheathing bases of the leaves. These
remain around the stems as dry, gray sheaths, even after the leaves have
fallen. The pseudobulbs of C. aurea are relatively slender when compared
with other species in the genus.

LEAVES: To 12 in. (30 cm) long but about 2 in. (5 cm) wide. Several medium
to light green leaves are produced along the length of the pseudobulb.
They are thin, somewhat wavy, rather soft-textured, strongly ribbed, taper
to a sharp point at the tip, and are deciduous at the end of the growing
season. 

INFLORESCENCE: To about 12 in. (30 cm) long, but usually shorter. The
inflorescence is produced from the axils of the new growth before the
leaves have developed. 

FLOWERS: 6-12 long-stalked, waxy, long-lived, fragrant blossoms are
produced on each inflorescence. The flowers are 1.6-3.0 in. (4.0-7.5 cm)
across but are usually about 2 in. (5 cm) and are somewhat variable in the
size and shape of the floral segments. The fleshy sepals and petals are
pale yellow at the base, yellow at the apex, with most of the inner
surface flushed with red to orange-brown. The fleshy, whitish lip, which
is marked with red-brown, is about 0.8 in. (2 cm) long and about 0.8 in.
(2 cm) wide if the normally upright side lobes are spread. The lip has
five parallel keels of equal length extending from the base to the
midpoint. The flowers of C. aurea variety maculata from Panama and Costa
Rica are said to be somewhat smaller than those of the type but are more
brightly colored. 

HYBRIDIZING NOTES: N/A. 

REFERENCES: . 

Bechtel, H., P. Cribb, and E. Launert. 1980. Manual of cultivated orchid
species. MIT Press, Cambridge, Mass.

Dressler, R. 1993. Field Guide to the orchid of Costa Rica and Panama.
Cornell University Press. New York. 

Dunsterville, G., and L. Garay. 1965. Venezuelan orchids illustrated, vol.
3. Orchid Herbarium of Oakes Ames, Botanical Museum, Harvard University,
Cambridge, Mass.

Fowlie, J. 1971. Obscure species: Three distinctive species of Chysis from
Central America. Orchid Digest 35(3):85-87. 

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

Hawkes, A. [1965] 1987. Encyclopaedia of cultivated orchids. Faber and
Faber, London. 

Pridgeon, A. ed. 1992. The illustrated encyclopedia of orchids. Timber
Press, Portland, OR. 

Pridgeon, A. 1986. Melting pot. American Orchid Society Bulletin 
55(8):812-814. 

Dressler, R. 1993. Field Guide to the orchid of Costa Rica and Panama.
Cornell University Press. New York. 

Williams, L., and P. Allen. [1946-1949] 1980. Orchids of Panama.
Monographs in systematic botany, vol. 4. Missouri Botanical Garden, St.
Louis, Mo. 

PHOTOS/DRAWINGS: . 


Copyright 1997, Charles O. Baker and Margaret L. Baker
Sheet version 566488

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

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