ORCHID SPECIES CULTURE
Charles and Margaret Baker

Masdevallia datura Luer and Vásquez

AKA: N/A. 

ORIGIN/HABITAT: Bolivia . Plants were found near Inquisivi, which is
between La Paz and Cochabamba. They were originally found in cloudforest
at 8200 ft. (2500 m). Later writings indicate they grow at 7850-9200 ft.
(2400-2800 m). 

CLIMATE: Station #85223, Cochabamba, Bolivia, Lat. 17.4S, Long. 66.2W, at
8367 ft. (2550 m). The record high temperature is 95F (35C), and the
record low is 20F (-7C). 

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX        74   75   78   79   78   77   75   74   76   77   76   74
F AVG MIN        35   39   46   50   52   53   54   53   51   46   39   34
DIURNAL RANGE    39   36   32   29   26   24   21   21   25   31   37   40
RAIN/INCHES     0.1  0.3  0.2  0.8  1.5  2.8  3.7  2.7  1.5  0.5  0.1  0.1
HUMIDITY/%       45   44   43   44   49   59   63   67   63   57   52   49
BLOOM SEASON                     *
DAYS CLR @ 8AM   21   19   16   12    9    5    4    2    6   12   17   18
DAYS CLR @ 2PM   20   18   12    8    6    6    4    2    6   13   16   17
RAIN/MM           3    8    5   20   38   71   94   69   38   13    3    3
C AVG MAX      23.3 23.9 25.6 26.1 25.6 25.0 23.9 23.3 24.4 25.0 24.4 23.3
C AVG MIN       1.7  3.9  7.8 10.0 11.1 11.7 12.2 11.7 10.6  7.8  3.9  1.1
DIURNAL RANGE  21.6 20.0 17.8 16.1 14.5 13.3 11.7 11.6 13.8 17.2 20.5 22.2
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations: 

LIGHT: 800-1500 fc. Light should be filtered or diffused, and plants
should never be exposed to direct sun. Strong air movement should be
provided at all times. When evaporative coolers are used, plants thrive
when placed in the strong, cool, moist airflow near the outlet. 

TEMPERATURES: Summer days average 74-77F (23-25C), and nights average
53-54F (12C), with a diurnal range of 21-24F (12-13C). 

HUMIDITY: 60-65% in summer are early autumn, dropping to 45-50% for most
of the year at the weather station. Averages in the cloudforest habitat
are probably much greater than indicated, however. 

WATER: Rainfall is light to moderatre during most of the year. More
moisture is probably available in the cloudforest habitat than is
indicated in the climate table, however. Cultivated plants should be kept
moist with only slight drying allowed between waterings. Water may be
gradually reduced in late autumn, however.

FERTILIZER: A balanced fertilizer mixed at 1/4-1/2 recommended strength
should be applied every 3-4 weeks if plants are grown in sphagnum moss,
tree-fern fiber, or osmunda. If grown in fir bark, the applications should
be made every 1-2 weeks. Many growers prefer to switch from the normal
balanced formula and make an application of high nitrogen fertilizer early
in the year when plants are actively growing. They may then make an
application of a high phosphate or "bloom booster" formula in late summer
or autumn in order to promote flowering. 

REST PERIOD: Winter days average 74-75F (23-24C), and nights average
34-39F (1-4C), with a diurnal range of 36-40F (20-22C). Water should be
reduced for cultivated plants in winer, especially those grown in the
dark, short-day conditions common in temperate latitudes. Plants may be
allowed to dry out somewhat between waterings, but they should never
remain dry for long periods. Fertilizer should 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.
Several waterings a day may be necessary for mounted plants during very
hot, dry periods. Because most growers find it difficult to keep mounted
plants moist enough, they are usually grown in pots using an open, fast
draining medium which contains materials that retain some moisture such as
chopped sphagnum and perlite. Charcoal is often added to help keep the
medium open and prevent it from becoming sour. Most growers recommend that
plants be repotted every year. Repotting is usually done in late winter or
early spring, but it may be done anytime between autumn and spring that
does not interfere with flowering. 

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

Plant and Flower Information:

PLANT SIZE AND TYPE: A 5-8 in. (13-20 cm) sympodial epiphyte. 

PSEUDOBULB: The secondary stems are 0.8-1.8 in. (2.0-4.5 cm) long. They
are erect and enclosed by 2 loose, ribbed, tubular sheaths. 

LEAVES: 4.3-6.3 in. (11-16 cm) long including the 1.2-2.0 in. (3-5 cm)
petiole. The erect leaves have leathery, narrowly elliptical to
linea-elliptical blades that are 0.4-0.6 in.(1.0-1.5 cm) wide. 

INFLORESCENCE: 2.4-3.5 in. (6-9 cm) long. The peduncle emerges near the
base of the secondary stem. The floral bract is 0.5 in. (1.2 cm) long,
which is almost as long as the 0.5-0.6 in. (1.2-1.5 cm) flower stalk. 

FLOWERS: One per inflorescence. The large, showy, snow-white blossoms are
said to remind viewers of a species of Datura. The sepals are white but
are lightly suffused with yellow. Also, they are veined in light yellow
toward the base, with a small brown spot on either side. The dorsal sepal
is 1.5 in. (3.7 cm) long, 0.5 in. (1.3 cm) wide, and connected to the
lateral sepals for 1.3 in. (3.4 cm), which is most of its length, to form
a long, horizontal, trumpet-shaped tube. The triangular free portion at
the tip contracts into a slender, erect, yellow tail that is 2.2-2.6 in.
(5.5-6.5 cm) long. The lateral sepals are 1.9 in. (4.7 cm) long, 1.4 in.
(3.5 cm) wide, and are connected to each other for 1.7 in. (4.3 cm). Their
tips contract into slender tails that are 1.7-2.2 in. (4.3-5.5 cm) long.
The petals, lip and column are also white. 

HYBRIDIZING NOTES: N/A. 

REFERENCES: Masd0, IKs18, [Phytologia 54(5):380 (1983)]. 

PHOTOS/DRAWINGS: . 


Copyright 1997, Charles O. Baker and Margaret L. Baker
Sheet version 546550

.........................................................................
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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    "Orchid Species Culture Vol. 1 - Pescatorea, Phaius, Phalaenopsis,
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