Orchids by general alliance

[prem]

This list is far from comprehensive (just off the top of my head), but here goes, a breakdown of general alliance followed by commonly cultivated species of each:

Cattleya alliance:

Cattleya
Laelia
Brassavola
Schomburgkia
Sophronitis
Epidendrum
Encyclia (and related genera)

Dendrobium alliance:

Dendrobium
Bulbophyllum
Cirrhopetalum
Mastigion

Dockrillia
Epigenium
Eria

Cymbidium alliance:

Cymbidium
Cymbidiella
Catasetum/Clowesia
Grammatophyllum
Cycnoches
Chysis
Mormodes
Ansellia
Stanhopea
Gongora
Cirrhaea
Cyrtopodium
Eulophia
Oeceoclades

Pleurothallid alliance:

Pleurothallis
Masdevallia
Dryadella
Dracula
Zootrophion

Vanda alliance:

Phalaenopsis
Doritaenopsis
Vanda
Ascocentrum
Neofinetia
Angraecum
Jumellea
Aeranthes
Aerides
Aerangis
Dendrophylax
Campylocentrum

Arethusinae:

Sobralia
Bletia
Bletilla
Phaius
Arundina
Spathoglottis
Calopogon

Cypripedium alliance:

Cypripedium
Selenipedium
Paphiopedilum
Phragmipedium
Mexipedium

Oncidium alliance:

Brassia
Miltonia
Miltoniopsis
Oncidium
Odontoglossum
Tolumnia
Comparettia
Ionopsis
Notylia

Maxillaria alliance:

Maxillaria
Zygopetalum
Lycaste
Anguloa
Bollea
Huntleya

More miscellaneous (although they do have their own alliances):

Habenaria/Platanthera/Pecteilis
Vanilla
Sacoila
Stenorrhynchos
Ludisia
Anoectochilus
Malaxis
Liparis
Macodes
Pleione

---Prem

[LJA]

...And if you're still not sure, just use this forum to ask.