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. |
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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. |
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Channel: a furrow, groove or longitudinal depression often between two ridges on the labellum surface. |
Papillae: small variously shaped protruberances on the labellum surface. |
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Erect pillar-like structure(s): an erect structure resembling a column or pillar. |
None: the labellum surface is generally flat and without ornamentation. |