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Various stuctures or ornamentations occur on the upper surface and margins of the labellum. These structures may aid in attracting a pollinator, produce nectar or their purpose may be unclear.
|  | Glands/calli: the labellum is adorned with gland-like structures termed calli. |  | Hairs: unicellular or multicellular hairs. | 
|  | Longitudinal ridge(s): raised structures that usually run longitudinally along the labellum. Often these ridges are a different colour to the labellum and may be wavy or break up into calli. In some epiphytes a ridge can run transversely across the labellum. |  | Plate(s): a smooth, flat, relatively thin, rigid body of uniform thickness. | 
|  | Channel: a furrow, groove or longitudinal depression often between two ridges on the labellum surface. |  | Papillae: small variously shaped protruberances on the labellum surface. | 
|  | Erect pillar-like structure(s): an erect structure resembling a column or pillar. |  | None: the labellum surface is generally flat and without ornamentation. |