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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 <firstname.lastname@example.org> __________________________________________________________________________ "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. __________________________________________________________________________