ONCIDIUM 



ONCIDIUM 



2341 



range in size from smiill erei't. forms, scarcely (i in. in 

 height (O. immiltiin), to tliose resembling O. o//i'.sn('hiuw, 

 with immense climbing panicles 9-V2 ft. high and cov- 

 ered with nvnuerons medium-.sized fls. The prevailing 

 color of the lis. i.s yellow, spotted and barred with 

 brown. White or rose-colored fls. occur in a few rare 

 examples (0. hicurt'um. O. urnitliorhi/nrhiDn). 



As a da-ss, oncidiuins are short-lived imiier cultiva- 

 tion. Few growers succeed in maintaining them in 

 good condition for any great length of time. The stock 

 is constantly renewed from the tropics. 



Cultivation of oncidiuins. 



The genus Oncidiiun embraces a great number of 

 species which arc found growing under such peculiar 

 and varied conditions in their native homes that imita- 

 tion of the same is usually impracticable and often quite 

 impossible. A fair degree of success, however, may 

 be obtained by careful observation and distribution of 

 the exceptionally difficult species among the several 

 orchid departments. 



The Sarcoptera section, which embraces such species 

 as 0. Canndislnanum, O. Lanccaniim, 0. luridum, O. 

 pulvinatum and others of similar structure, and the 

 O. Papilio section, with O. ampliatuin, may be suc- 

 cessfully grown in a bright warm portion of the 

 cattleya department in small ba.skets suspended from 

 the roof, using for a compost a mixture of clean chopped 

 peat and sphagnum mo.ss, freely interspersed with 

 lumps of broken charcoal. O. cucidlaium, 0. incurvum, 

 O. macranlhum, 0. ornithoi-hynchum, O. Phalx)iopsis,0. 

 varicosum , with a few others of like nature, do well 

 under treatment similar to that given for odontoglos- 

 sums, which see. 



When a good collection of species is cultivated, a 

 large number, incluchng many of the above, can be 

 readily grown in one house if it be especially adapted to 

 them. Such a house should be a span-roof structure of 

 east and west exposure, at an angle of about 40°, which 

 will admit the longest possible light. The early morning 

 and late afternoon sun striking the glass at right angles 

 produces and prolongs the natural sun heat for a greater 

 part of the day, while at midday, when the outside 

 temperature is highest, the sun's rays strike the glass 

 obliquely, giving less heat, with little danger of the 

 plants becoming sunbimied from lenses in the glass. 

 Oncidiums require more sun and air than most orchids. 



The benches may be of either wood or stone, and 

 should be covered an inch or two in depth with sand, 

 ashes or gravel. The benches and paths should be wet 

 down once or twice daily to insure a moist atmos- 

 phere. Ventilators should be arranged on both sides of 

 the roof: air may then be freely admitted without caus- 

 ing direct drafts on the plants by using the ventilators 

 on the sheltered side. In winter the temperature should 

 range from .50° to 5.5° F. at night and 60° to 6.5° by 

 day, or a few degrees more with sun heat and ventila- 

 tion. In summer it must be kept :us low- as outside con- 

 ditions will permit. From March until October, shar 

 ding must be apphed to the glass sufficiently hea\T to 

 keep down the temperature without excluding indirect 

 solar influence. A good shading is made of turpentine 

 and white leafl; it stands well and is easily removefi. It 

 can be applied rapiflly with a whitewa.sh brush on a 

 long pole, and removed with a hanl bnish in the fall. 



Oncidiums may be growii in cither pots or Ixuskets, 

 but as many species are of rambling habit, the latter are 

 preferable. The tiny species, such a.s O. Limminqliii, 

 Act best on blocks witli little compost beneath them. 

 Clean chopped peat fiber and live si)hagnum moss, equal 

 parts, make the best general growing material, and 

 this should be liberally interspersed with broken pieces 

 of charcoal. The plants in all cases must be securely 

 fastened, and the compost must be pres.sed in moder- 

 ately firm, but should be u.sed sparingly. Overhea<l 



syringing should be given fn-quently, about once or 

 twice a day in bright weather, but care must be taken 

 not to keep the compost too wet, for the roots are lia- 

 ble to decay: it is advisable to let them dry out occa^ 

 sionally. 



Stock is increa.sed by division or notching the rhizome 

 between the pseudobulbs just before the growing season, 

 allowing about three or four pseudobulbs to each piece 

 and separating the parts after the first growth is 

 matured. 



For other cultural notes on the genus, see the vari- 

 ous manuals on orchid-growing. 



Robert M. Grey. 



albiflorum, 31. 

 album, 31. 

 altissinium, 24, 25. 

 ampliatum, 19. 

 atratum, 7. 

 aurosum, 20. 

 Barkeri, 21. 

 Batemannianum, 28. 

 Baueri, 24. 

 bicalloaum, 40. 

 bicoloT, 12. 

 Bradshawffi, 7. 

 carthaginense, 43. 

 Cavendishianmii, 41. 

 Cebolleta, 48. 

 Charlcsworthii, 14. 

 cheirophorum, 37. 

 concolor, IS. 

 cornigerum, 10. 

 crispum. 9. 

 Crista-galli, 39. 

 Crookii, 21. 

 cucullatum, 11. 

 curtum, S. 

 dasystyle, 17. 

 divaricatum, 32. 

 Eckhardtii, 45. 



INDEX. 



excavatum, 20. 

 flexuosuin, 13. 

 Forbcsii, 7. 

 grandiflorum, 9,21, 26, 

 guttatuni, 44. 

 Harrisianum, 29. 

 Harrisonianum, 29. 

 hastiferum, 5. 

 Henchmaiinii, 43. 

 incurvum, 23. 

 iridifotium, 39. 

 janeirtnse, 16. 

 Joncsianum, 47. 

 juncifolium, 48. 

 Kramcrianuni, 46. 

 Lanccanum, 42. 

 leucochilum, 30. 

 Limminghii, 3C. 

 longipcs, 16. 

 Louvroxianum, 42. 

 luridum. 44. 

 macranthum, 5. 

 maculatum, 35. 

 majus, 19, 31, 33. 

 Marshallianum, 6. 

 Martianum, 12. 

 micropogon, 1. 



moortebeekiense, 14. 

 nubigoiium, 11. 

 ornithorliynchum, 31. 

 Papilio, 45. 

 Phalynopsis, 15. 

 phyniatochilum, 2. 

 pulvinatum, 33. 

 pumilum, 38. 

 reflexum, 27. 

 rhodoptera, 18. 

 Rogersii, 14. 

 roseum, 43, 44. 

 sanguineum, 43. 

 serratum, 3. 

 sphacclatum, 26. 

 splendens, 30. 

 splcndidum, 22. 

 sulphureum, 6. 

 superbiens, 4. 

 superbum, 1, 42. 

 tigrinuni, 21. 

 triquetrum, 49. 

 uiidulatum, 43. 

 unguiculatum, 18, 21. 

 unicolor, 13. 

 varicosum, 14. 

 Warneri, 34. 



SYNOPSIS OF SECTIONS. 



A. Lvs. plane, not terete. 

 B. Labellum smaller than the sepals and petals. . . 



Species 1-5 

 BB. Labellum at least as large as the other segms., 

 often greatly exceeding them, 

 c. Lateral sepals more or less united at base. 



Species 6-18 

 cc. Lateral sepals free. 



D. All the segms. liaving a distitict blade, 

 none of them Hnrar-subterete. 



E. Pscudobulhs present Species 19-37 



EE. Pseudobidhs wfi riling or obsolete Species 38-44 

 DD. Only lateral scpah with distinct blade; 

 dorsal sepal and petals elongate, linear, 



erect, with an obsolete blade Species 45-46 



AA. Lvs. terete or subterete Species 47-48 



AAA. Lvs. sublriangular in section Species 49 



DESCRIPTION OP SPECIES. 



A. Lateral sepals united at base 1. micropogon 



AA. Lateral srpals free. 



B. Sepals and petals linear, flaccid. ... 2. phymato- 



[chilum 

 BB. Sepals and petals broad, serrate. ... 3. serratum 

 BBB. Sepals and petals broad, entire or 

 suhentire. 



c. Fls. brown 4. superbiens 



cc. Fls. yellow 5. macranthum 



1. micropogon, Rcichb. f. Pseutlobulbs almost in 2 

 rows on the rhizome, broadly ovoid: lvs. 4—6 in. long, 

 linear-obkmg, rounded at the to]), leathery: raceme 

 8-10 in. long, on a long stalk, fle.xnous, pendulous; fls. 

 1)^ in. across; sepals linear-oblong, vindulate, yellow, 

 barred with brown; petals clawed, orbicular, yellow, 

 with a deej) red-brown claw; labellum yellow, smaller 

 than the [lotals, having 3 almost equal, rounded, clawed 

 lobes. .\ug. Trop. Amer. B.M.6971. Gt. 4:308. Var. 

 superbum, Ilort., is ailvcrtised. 



2. phymatochilum, Liiidl. Pseudobulbs broadly fusi- 

 fonn, P.5 in. long, purplish browTi, with several large 



