Pseudopollen and Food-hair Diversity in Polystachya Hook. (Orchidaceae)

• DOI: 10.1093/aob/mcf220
• Publication Date: 2002-09-25T22:41:48Z
• Authors: K. L. DAVIES
• Keywords: Trichome; Orchidaceae; Bristle

Labellar food‐hairs in Polystachya Hook. exhibit considerable morphological diversity. The commonest type of trichome is uniseriate, two to four‐celled, with a clavate or subclavate terminal cell. This occurs amongst representatives most sections examined. Other trichomes are bristle‐like tapering fusiform cells, whereas section have moniliform that fragment the formation rounded elliptical component cells. Most contain protein and, while some starch, lipid invariably absent. presence particular types labellar does not coincide variations vegetative morphology. Thus, current taxonomic treatment genus indicates types, perhaps sole exception moniliform, pseudopollen‐forming hairs found only, limited value. However, remarkable similarity between and those Neotropical Maxillaria terms morphology, cellular dimensions food content pseudopollen may arisen several times evolved response similar pollinator pressures.