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(Last Modified On 11/8/2012)
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(Last Modified On 2/4/2013)
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Family
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ORCHIDACEAE
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Contributor
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LOUIS 0. WILLIAMS
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Description
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Epiphytic, terrestrial, rarely semi-aquatic or saprophytic, perennial herbs. Vegetative growth of two main types: (1) Termed MONOPODIALES, in which the main axis or stem grows steadily upward year after year, the annual growths at length being indistinguishable and a monopodium being formed; the inflorescences borne on lateral shoots. (2) Termed SYMPODIALES, in which a new growth de- velops laterally from the base of the previous year's growth, which is completed and matures in a few months. In the SYMPODIALES if the annual growth is terminated by an inflorescence the plant is termed acrantbous (terminal flower- ing); if the inflorescence originates on lateral branches (usually at the base of or laterally on a pseudobulb) and the annual growth is terminated only by leaves the plant is termed pleu-ranthous (lateral flowering). Stems (secondary) of many orchids developed into thickened or swollen structures (pseudobulbs) which act as storage organs for food and moisture. Flowers hermaphroditic and gynandrous, occasionally monogamous or polygamous, the male and female ones being very different; zygomorphic; superior. Perianth of two tripartite whorls, alternating, often variously united; in the same whorl the even pair similar, the odd one usually different in form. Sepals 3, similar, or the dorsal differing from the laterals, free or variously united. Petals 3, two similar and termed petals, the other one usually strikingly different and termed lip or labellum. Stamens in two tripartite whorls, only one (MONANDRAE) or two (DIANDRAE) fertile, the others, along with the styles and sterile stigmas, forming the column by consolidation; in the MONANDRAE the odd stamen of the outer whorl fertile; in the DIANDRAE the paired stamens of the inner whorl fertile. Pollen (except, in the CYPRIPEDILOIDEAE) usually consolidated into pollinia. Stigmas 3, usually only one or two fertile (if two, often confluent and appearing as one). The column, the central structure in the flowers, which is made up of the consolidated styles and filaments along with the suppressed anthers and stigmas, is diagnostic of the family. Fertile anthers and stigmas usually borne toward the apex of the column. Ovary 1-celled or rarely 3-celled. Seeds numerous, minute, lacking endosperm.
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Note
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A cosmopolitan family of about 600 genera and 15,000-20,000 species. Most abundant in tropical regions of the, world. The Orchidaceae is an extremely complex family, the morphology of which is often not too well understood. The genera, in some groups, are technical and per- haps not too well differentiated; in other groups they are fairly well differentiated. With the exception of a few terrestrial genera and even fewer of the epiphytic ones, the respective genera are limited to either the eastern or to the western hemis- phere. A few genera contain a very large number of species (Dendrobium, eastern hemisphere, probably more than 1000; Epidendrum, western hemisphere, possibly nearly 1000). The species of orchids, as a whole; are distinctive, and extreme variation within species is not too common. Terrestrial species, especially those of temperate climates, are inclined to be more variable than are epiphytic ones. Species are inclined to be restricted in distribution -although terrestrials and epiphytes growing at low elevations often range widely. The greatest concentrations of orchids occur within twenty degrees of the equator. 'While some are found at low elevations, the great majority of them grow on mountains within the tropics. Malaysia and tropical America are richest in species and genera, with Africa a poor third. New Guinea probably contains more species than any comparable land area, although it is still not well known botanically. Colombia is perhaps the richest in species of any comparable area in the western hemisphere.
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Key
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KEY TO THE SUBFAMILIES, TRIBES AND GENERA
a. Stamens 2, a third usually transformed into a large staminode; pollen granular, not united into masses or bodies ........ Subfamily DIANDRAE (Tribe I CYPRIPEDIOIDEAE)
aa. Stamen 1, the laterals abortive or forming staminodes; pollen consolidated into masses or solid bodies (pollinia) ..... Subfamily MONANDRAE
b. Caudicle and gland arising from the base of the pollinia; anthers erect or more or less resupinate, very closely adnate to the broadbased column, never deciduous after flowering; pollinia always granular (sectile) ......... Tribe II OPHRYDOIDEAE
bb. Caudicle and gland arising from the apex of the pollinia; anthers erect or incumbent, the filaments short and slender, generally narrowly joined to the column, usually deciduous but if persistent soon withering.
c. Pollinia granular, soft; anthers commonly persistent but withering; inflorescence (normally) always terminal ....... Tribe III POLYCHONDREAE
cc. Pollinia waxy or cartilaginous; anther commonly soon deciduous; inflorescence terminal or lateral ......... Tribe IV KEROSPHAEREAE
I. Subfamily DIANDRAE, Tribe CYPRIPEDILOIDEAE. Two genera in Panama.
a. Stems elongated, leafy; leaves thin ....................................................... 1. SELENIPEDIUM
aa. Stems very short or apparently none, leaves coriaceous ............................ 2. PHRAGMIPEDIUM
II. Subfamily MONANDRAE, Division BASITONAE, Tribe OPHRYDOIDEAE. a. One genus in Panama ......................... 3. HABENARIA
III. Subfamily MONANDRAE, Division ACROTONAE, Tribe POLYCHONDREAE. Twelve genera distributed in five subtribes in Panama.
a. Anther more or less prone, incumbent.
b. Leaves not articulated, persistent; stems not cane-like.
c. Terrestrial herbs with fleshy roots; small or large rather showy purplish flowers .......................... 4. POGONIA
cc. Scandent herbs, usually epiphytic, without fleshy roots; flowers large, usually white ...... 5. VANILLA
bb. Leaves articulated, caducous; stems cane-like.
c. Pollinia 8.
d. Base of the lip strongly gibbous or subsaccate, ornamented with two prominent calli; flowers relatively small..... 6. ELLEANTHUS
dd. Base of the lip not strongly gibbous or subsaccate, with or without calli at the-base; flowers relatively very large ........ 7. SOBRALIA
cc. Pollinia 4 ......................................................... 8. PALMORCHIS
aa. Anther more or less erect; rostellum erect or suberect.
b. Leaves not plicate-nerved, usually soft.
c. Roots fasciculated.
d. Lip uppermost, adaxial; flowers not resupinate.
e. Petals, and sometimes the lip, inserted on the column ............ 12. PONTHIEVA
ee. Petals and lip not inserted on the column.
f. Lip inserted at the base of the column, free.
g. Sepals not united into a basal tube ..................................... 11. CRANICHIS
gg. Sepals united at the base into a slender tube ...................... 9. STENOPTERA
ff. Lip united at the base to a cup formed of the united sepals, helmet-shaped ......................... 10. PRESCOTTIA
dd. Lip lowermost, abaxial; flowers resupinate ................................... 13. SPIRANTHES
cc. Roots not fasciculated, arising from the nodes on the lower part of the stem or rhizome ..... 14. ERYTHRODES
bb. Leaves plicate-nerved, chartaceous or subcoriaceous ............................. 15. CORYMBORCHIS
IV. Subfamily MONANDRAE, Division ACROTONAE, Tribe KEROSPHAEREAE. Seventy-two genera, distributed in twenty-six subtribes, in Panama.
a. Series A. ACRANTHAE. Inflorescence normally terminal or by abortion of terminal inflorescence axillary in uppermost leaves. (See also LOCKHARTIA).
b. Viscid disc, when present, arising from the apex of the pollinia, commonly irregular, rudimentary or none.
c. Ovary articulated to the pedicel; pedicel persistent; stems slender, rigid, sometimes reduced, usually unifoliate.
d. Sepals all distinctly connate at the base.
e. Sepals also connate at their tips, open between tips and bases.... 18. CRYPTOPHORANTHUS
ee. Sepals not connate at their tips.
f. Sepals forming a narrow or campanulate tube at the base.
g. Inflorescence a raceme ......................................................... 17. PHYSOSIPHON
gg. Inflorescence a single flower, or rarely 2 flowers .............. 19. MASDEVALLIA
ff. Sepals more or less iotate, not forming a narrow tube at the base ... ...................... 16. STELIS
dd. Sepals not all distinctly connate at the base, at least the dorsal sepal free or nearly free.
e. Blade of the petal transverse, i. e. strongly bilobed (except L. exinia) ....... 21. LEPANTHES
ee. Blade of the petal not transverse, not strongly bilobed.
f. Petals inserted on the column-foot; lip with a hood-shaped callus or ligule at the base ......... 22. ACOSTAEA
ff. Petals not inserted on the column-foot nor with a hood-shaped callus or ligule at the base.
g. Inflorescence terminal or at least subterminal on the secondary stems ................. 23. PLEUROTHALLIS
gg. Inflorescence originating about the middle of the secondary stems ...................... 20. SCAPHOSEPALUM
cc. Ovary not articulated to the pedicel; pedicel caducous with the flower; stems slender or fleshy, 1- to several-flowered.
d. Pollinia without appendages, i. e. no viscid disc or caudicle.
e. Column very short; anthers sessile in the clinandrium, erect .... 24. MALAXIS
ee. Column elongated; anther terminal, incumbent ...................... 25. LIPARIS
dd. Pollinia appendaged, i. e. with at least a rudimentary viscid disc or a caudicle with a viscid apex.
e. Column footless; lip more or less connate with the base of the column.
f. Pollinia 4, two in each cell of the anther.
g. Lip geniculate at its junction with the column ................ 26. HEXISEA
gg. Lip not geniculate at its junction with the column.
h. Flowers large and showy; stems always pseudobulbose.. 29. CATTLEYA
hh. Flowers usually not large and showy; stems either pseudobulbose or ebulbose.
i. Lip with two large hollow horn-like processes; lip free or nearly so................................... 28. DIACRIUM
ii. Lip without hollow horn-like processes; lip commonly connate with the column at base but not always so ................ 27. EPIDENDRUM
ff. Pollinia 8, four in each cell of the anther.
g. Pollinia of two sizes, unequal............................................. 31. BRASSAVOLA
gg. Pollinia of one size, equal ...................................................... 30. LAELIA
ee. Column produced into a distinct foot at the base; lip hardly connate to the column or at most connate at the base of the column-foot. f. Pollinia 4 or 6.
g. Leaves distichous and scattered along an elongated stem.
h. Pollinia 6 ......... 33. PLATYGLOTTIS
hh. Pollinia 4 .................................. 34. ISOCHILUS
gg. Leaves not distichous on an elongated stem, terminal from pseudobulbs or short indurated stems ........... 32. SCAPHYGLOTTIS
ff. Pollinia 8 ...................................................................... 35. COELIA
bb. Viscid disc distinct, regular, with the margins well defined, arising from the apex of the column.
c. Column with a foot; plants with pseudobulbs; pollinia 4, or 4 joined into two pairs.
d. Lip with a spur ................ 37. GALEANDRA
dd. Lip without a spur ................ 36. POLYSTACHYA
cc. Column footless; plants without pseudobulbs; pollinia 2 .................. 38. EPIDANTHUS
aa. Series B. PLEURANTHAE. Inflorescence lateral, arising near the base of the pseudobulb or in the axils of the lower leaves or sheaths. (This series contains two subseries.)
A. Subseries a. SYMPODIALES. Plants forming a sympodium, i. e. the stems approximate or superimposed and the apical growth manifestly terminal.
B. Pollinia without a stipe; viscid disc commonly rudimentary or the apex of the caudicle glutinous or none.
C. Rhizome short; terrestrial plants with the stems bulbose, usually partially buried in the ground; leaves plicate
D. Lip with a spur ............ . 39. CALANTHE
DD. Lip without a spur ....................................................... 40. BLETIA
CC. Rhizome more or less elongated; plants epiphytic with pseudobulbose stems 1- to many-leaved; leaves plane or plicate.
D. Pseudobulbs homoblastic (i. e. of several nodes, only the terminal one of which bears leaves), fusiform, many-leaved; leaves plicate, thin; flowers relatively large ............................................. 41. CHYSIS
DD. Pseudobulbs heteroblastic (i. e. of a single node with one or more terminal leaves), usually small; leaves coriaceous or fleshy, not plicate; flowers relatively small ............................................... 42. BULBOPHYLLUM
BB. Pollinia with a prominent stipe, sometimes short; viscid disc distinct.
C. Pollinia, of a waxy texture, easily mashed.
D. Lip spurred or with a saccate base ................................................ 43. EULOPHIA
DD. Lip not spurred nor saccate at the base.
E. Lateral sepals and column forming a prominent mentum; base of the leaves and peduncle not enclosed in a submembranaceous sheath.......................................................................... 44. WARREA
EE. Lateral sepals and column-foot forming an inconspicuous mentum; base of the leaves and peduncle enclosed in a submembranaceous sheath.................................................................. 45. GOVENIA
CC. Pollinia cartilaginous in texture, not easily mashed.
D. Leaves convolute in vernation.
E. Pseudobulbs large, fusiform, homoblastic, many-leaved.
F. Flowers perfect, monomorphic; column twisted ................ 46. MORMODES
FF. Flowers dimorphic or trimorphic (rarely perfect); column not twisted.
G. Column thick, straight, in male flowers usually with two retrorse antennae .............. 47. CATASETUM
GG. Column slender, curved or arcuate, without retrorse antennae .............................................. 48. CYCNOCHES
EE. Pseudobulbs short, heteroblastic, 1- to few-leaved.
F. Lip continuous with the base of the column or solidly attached to the short column-foot, not articulated, more or less prominently divided into an epichile and a hypochile or rarely entire.
G. Petals very much narrower than the sepals, usually inserted on the base of the column.
H. Epichile saccate and bucket-like .................................... 57. CORYANTHES
HH. Epichile not saccate ........................ ........................ 56. GoNGORA
GG. Petals not distinctly narrower than the sepals, from a little narrower to broader.
I. Epichile saccate and bucket-like ........................... 57. CORYANTHES
HH. Epichile not saccate. I. Lateral sepals connate and forming a distinct mentum. at the base; flowers about 1.5 cm. long, fleshy ......................................................................... 49. COELIOPSIS
II. Lateral sepals free or if connate not forming a distinct mentum at the base.
J. Lip entire ........................................ 50. SIEVEKINGIA
JJ. Lip not entire, usually divided into a hypochile and an epichile.
K. Hypochile of lip concave-saccate; apex of lip shallowly 3-lobed, the epichile obscure ........... 55. STANHOPEA
KK. Hypochile of lip usually not concave-saccate or if so then the lip distinctly divided and lobed.
L. Epichile or terminal lobe of lip narrowly lanceolate, acuminate ........................................ 54. NEOMOOREA
LL. Epichile or terminal lobe of lip not narrowly lanceolate, acuminate.
M. Lateral lobes of the lip (pleuridia, mesochile) erect or at least not parallel to the epichile.
N. Rachis of inflorescence and sepals dorsally ,brown pilose-pubescent ................... 51. KEGELIELLA
NN. Rachis of inflorescence and sepals not pubescent.
0. Lateral lobes of the lip joined by a large central callus; hypochile of the lip long, at least as long as the lateral lobes .............................................. 52. ACINETA
00. Lateral lobes of the lip not joined by a central callus; hypochile of the lip short and inconspicuous .... 53. PERISTERIA
MM. Lateral lobes of the lip (pleuridia) more or less parallel to the epichile, ensiform.... 55. STANHOPEA
FF. Lip articulated to the apex of the column-foot.
G. Inflorescence basal, i. e. arising from the base of the pseudobulb; lip usually provided with a long low callus.
H. Inflorescence consisting of a single flower .................... 60. LYCASTE
HH. Inflorescence a few- to several-flowered raceme.
I. Flower with a conspicuous spur-like mentum ............ 58. XYLOBIUM
II. Flowers without a conspicuous spur-like mentum .... 59. BIFRENARIA
GG. Inflorescence suprabasal, i. e. in the axils of the lower sheaths; lip usually provided with a transverse callus or crest ..... 61. ZYGOPETALUM
DD. Leaves conduplicate in vernation.
E. Column produced into a foot and forming a mentum with the lateral sepals; rostellum hardly produced, emarginate.
F. Callus of the lip transverse, often flabellate, at the base of the lip; inflorescence, suprabasal, i.e. in the axils of the sheaths or sheath-like leaves; pseudobulbs reduced or rudimentary.
G. Callus at the base of the lip pectinate or fringed 64. HUNTLEYA
GG. Callus at the base of the lip not pectinate or fringed.
H. Lip entire or but obscurely lobed .................................. 62. CHONDRORHYNCHA
HH. Lip lobed, or divided into a narrow basal and a broad apical part .. 63. WARSCZEWICZELLA
FF. Callus of the lip longitudinal, often inconspicuous or rarely none; inflorescence borne from the base of a pseudobulb;. pseudobulbs often well developed or forming elongated stems.
G. Lateral sepals forming a spur at their base about as long or longer than the blades of the sepals .......... 67. CRYPTOCENTRUM
GG. Lateral sepals not forming a long spur.
H. Sepals connate and forming a short tube at the base; lip not half as long as the sepals.......... 66. TRIGONIDIUM
HH. Sepals not connate and forming a tube at the base; lip usually at least half as long as the sepals ........... 65. MAXILLARIA
EE. Column footless; rostellum commonly produced, sometimes subulate or acute.
F. Anther incumbent; rostellum porrect. or deflexed, never ascending.
G. Base of the lip spurred or saccate or appendaged at the base.
H. Base of lip forming a spur or deeply saccate.
I. Lateral sepals free .............................. 68. TRICHOCENTRUM
II. Lateral sepals connate .............. 70. RODRIGUESIA
HH. Base of the lip with short to long appendages; lateral sepals usually connate and commonly spurred or saccate at the base .. 69. IONOPSIS
GG. Base of the lip neither spurred nor saccate nor with appendages.
H. Pollinia 2.
I. Clinandrium low, slightly excavated, margin entire and not hyaline.
J. Column winged near the stigma ........... 71. TRIZEUXIS
JJ. Column wingless near the stigma ............................ 76. BRASSIA
II. Clinandrium with a high margin enfolding the anther or nearly so, or the column with spreading wings near the stigma.
J. Leaves articulated at the base.
K. Base of the lip enfolding the column and shortly adnate to it at its base .......... 72. TRICHOPILIA
KK. Base of the lip not enfolding the column. L. Lip inserted on the column near the middle ..... 75. ASPASIA
LL. Lip not inserted on the column near the middle.
M. Lateral sepals or all sepals and petals long-caudate; column not winged near the stigma............. 76. BRASSIA
MM. Lateral sepals or all sepals and petals not caudate, or if so then column winged near the stigma.
N. Base of the lip forming a shallow sac.... 73. MESOSPINIDIUM
NN. Base of the lip not forming a shallow sac.
0. Column with a pair of narrow stelidia at the middle; lip usually unlobed, pandurate or retuse ...... 79. LEOCHILUS
00. Column lacking narrow stelidia at the middle; lip various.
P. Lip long-unguickulate; flowers small................. 80. SIGMATOSTALIX
PP. Lip not long-unguiculate; flowers usually not small.
Q. Lip erect and parallel or contiguous to the column at the base; calli on the lip usually 2, parallel and not joined; column usually not winged.................... 74. ODONTrOGLOSSUM
QQ. Lip spreading (usually approaching a right angle) from the column; calli on the lip various but if 2 then usually joined; column usually winged at the apex.
R. Lip usually relatively large and not sharply lobed, usually lacking calli except at the base; flowers white .......... 77. MILTONIA
RR. Lip usually relatively small and distinctly 3-lobed, usually provided with calli above the base (as well as often at the base); flowers commonly yellow to maroon ..................... 78. ONCIDIUM*
JJ. Leaves not articulated, i. e. marcescent; plants with densely equitant-leaved, elongated stems, without pseudobulbs ....... 81. LOCKHARTIA
HH. Pollinia 4; lip with a retrorse callus near the base ...... 82. ORNITHOCEPHALUS
FF. Anther erect on the back of the column or erect on the apex of the column under the clinandrium; rostellum erect or ascending.
G. Column provided with stiff hairs ..................................... 85. TELIPOGON
GG. Column not-provided with stiff hairs.
H. Clinandrium margins small, not almost surrounding the anther................ 83. NOTYLIA
HH. Clinandrium margins large, almost forming a calyptra over the anther...................... 84. MACRADENIA
AA. Subseries b. MONOPODIALES. Plants forming a monopodium, i.e. the stems having infinite apical growth.
B. Column with an infrastigmatic ligule; stems. with equitant leaves.... 86. DICHAEA
BB. Column without an infrastigmatic ligule; stems not having equitant leaves, plants sometimes leafless ............. 87. CAMPYLOCENTRUM
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Note
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*Oncidium, Miltonia, Odontoglossum, Brassia, Aspasia, Leochilus and Mesospinidium are only one genus, naturally, for they merge completely. However for purposes of convenience they are best left apart. The first three mentioned are all well known and, except for borderline species, even the amateur can soon learn to distinguish them easily by their aspect.
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