This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
A. Sepals and petals not yellow.
b. Lip deeply fimbriate...............15. Devonianum bb. Lip entire or minutely fimbriate.
c. Nodes of pseudobulb much thickened. D. Pseudobulbs thick.
E. Internodes abruptly depressed-globose, thickened at apex... 16. pendulum EE. Internodes gradually thickened toward apex. f. Front lobe of lip ovate, reflexed, purple..........17. Linawianum ff. Front lobe of lip orbicular-ovate, yellow............18. Findlayanum dd. Pseudobulbs wand-like, slender... 19. Falconeri. cc. Nodes not thickened, or but slightly so. d. Internodes usually more than 5 times longer than broad.
E. Lip curved like a trumpet; sepals and petals purple.... 20. lituiflorum ee. Lip not curved.
f. Flowers white................21. monile.
FF. Flowers with sepals and petals white, tips colored. G. Throat of lip yellow. h. Middle lobe violet, white-margined......22. amoenum hh. Middle lobe yellow, tip rose...............23. crystallinum
GG. Throat of lip purple......24. transparens fff. Flowers with sepals and petals mauve, lip primrose......25. Pierardii
DD. Internodes usually less than 6 times longer than broad.
E. Flowers 2 1/2 in. across or less.
F. Color violet-purple.........26. Parishii ff. Color white or lilac.
a. Lip primrose-yellovr, sepals and petals lilac...27. primulinum GG. Lip with ground color white,a large light or dark yellow blotch in center. H. Blotch not marked; base plaited.........28. cre pi datum
HH. Blotch marked.
I. With 2 basal purple spots............29. Bensoniae
11. With reddish orange lines. J. Shape of lip obtuse; blotch light yellow.........30. cretaceum
JJ. Shape of lip acute; blotch deep yellow............31.gratiosissimum ee. Flowers exceeding 2 1/2 in. across.
F. Ground-color of sepals and petals white.
G. Throat deep purple... . .32. nobile gg. Throat yellow, with 2 purple spots.............33. Wardianum
FF. Ground-color of sepals and petals rose. G. Front lobe of lip rose, the throat yellow..........34. regium
GG. Front lobe of lip white-margined, the throat with 2 dark spots......35. rhodopterygium
AA. Sepals and petals yellow.
B. Lip deeply pectinate-fringed.........36. Brymerianum bb. Lip not fringed. c. Disk pilose; 2 large purple fringed spots at base of lip.............37. Dalhousieanum cc. Disk not pilose, nor with fringed spots d. The lip slipper-shaped.........38. moschatum
DD. The lip not slipper-shaped. e. Unicolored, yellow.
f. Shape of sepals and petals acute; lip minutely serrate 39. dixanthum ff. Shape of sepals and petals obtuse; lip fimbriate......40. fimbriatum ee. Bi-colored, yellow with purple markings. F. Apex of lip acute; sepals and petals pale yellow. G. Front lobe nearly rhomboid, cream-margined.. .41. Aphrodite gg. Front lobe ovate, red-lined, the apex recurved.......42. aureum ff. Apex of lip rounded; sepals and petals rich yellow.
G. Flowers 2 1/2 in. or more across; lip with a single large spot.
H. Lip serrate or shortly fimbriate; floral bracts large...............43. clavatum
HH. Lip fimbriate, the divisions branched; floral bracts small.........40. variety oculatum gg. Flowers about 2 in. across; lip with 2 spots........44. Gibsonii
Pseudobulbs up to 3 ft. long, round, pendulous: flowers single or in pairs, about 2 in. across; sepals and petals white tinted amethyst at the apex, the sepals about half as broad as petals, lanceolate, the petals ovate, acute, ciliate; lip white, fringed, the apex purple, and 2 orange blotches in the throat. N. India to S. China. B.M. 4429. J.II. III. 34:197; 52:317. G.C. III. 7:680. CO. 23. O.R. 4:177; 12:152.
Pseudobulbs abruptly swollen at the nodes, up to 2 ft. long, somewhat pendulous: flowers solitary or 2 or 3 together, 2-2 1/2 in. long; sepals and petals white, purple-tipped, acute, the petals broader than sepals; lip white, ciliate, pubescent on upper surface, the center yellow, the front margin purple. Moulmein. B.M. 5766 (as D. crassinode). CO. 19. O.R. 2:177; 8:177. variety Barberianum, Hort. Flowers brighter, the apical spots larger and deeper.
(D. moniliforme, Lindl., not Swartz). Pseudobulbs with internodes gradually thickened toward apex, up to 1 1/2 ft. long, clavate: flowers in pairs or 3's, about 2 in. across; sepals and petals rosy purple above, white below, the sepals half as broad as petals; lip obscurely 3-lobed, small, the front lobe purple, the lower part white with 2 purple spots on disk. China and Japan. B. M. 4153. P.M. 3:77.
Pseudobulbs with internodes gradually thickened toward apex, up to 1 1/2 ft. long: flowers in pairs, 2-3 in. across; sepals and petals pale lilac, the sepals much narrower than the petals; lip yellow, white-margined. Burma. B.M. 6438. Gn. 49:446. G.M. 44:373 (var roseum). O.R. 8:169.
Pseudobulbs slender, up to 1 1/2, ft- long: flowers solitary, 2-3 in. across; sepals and petals white, purple-tipped, the former tinged with pale rose, the petals broader than sepals; lip obscurely 3-lobed, the throat deep purple, with an orange spot on each side and a white band in front, the acute apex purple. N. India. B.M. 4944. I.H. 23:243. F.M. 1876:226. G.Z. 31:145. variety giganteum, Hort. Pseudobulbs larger: flowers larger and lasting longer.
Pseudobulbs up to 2 ft. long, pendulous: flowers in pairs, rarely more, 2-2 1/2 in. across; sepals and petals amethyst, the former paler at base, the latter the more richly colored, the sepals much narrower than the petals; lip curved like a trumpet, the opening turned up, the throat purple, surrounded by a white zone, the margin purple. Burma. B.M. 6050. variety candidum, Reichb. Flowers larger, the sepals and petals white, the lip sulfur-yellow. variety Freemanii, Hort. Sepals and petals deeper in color, the lip with a sulfur-yellow zone.