Silica bodies and hooked papillae in lemmas of Melica species (Gramineae: Pooideae)

Melica (sensu lato ) is a genus with approximately 80 species distributed in the temperate regions of both hemispheres. The genus has been better studied morphologically than anatomically, but morphological patterns have led to conflicting subdivisions either into sections, or by segregation of the genus Bromelica . The lemma epidermis is examined here under scanning electron microscopy (SEM) for 40 species of Melica to see if it exhibits characters of systematic significance. Silica bodies and hooked papillae are reported in the lemma for the first time in the genus. Patterns of variation are evident within four structures that terminate in points: prickles, hooks, hooked papillae and macro‐hairs. Fourteen qualitative characters for lemma epidermis are used in phenetic analyses. The presence or absence of macro‐hairs conflicts with some other patterns, but gives some support to the classification of Papp. Characters associated with the split of the clusters were micro‐hairs (straight and geniculate) and the distribution and frequency of prickles in both costal and intercostal zones. As a conclusion, Melica is not a coherent taxonomic grouping and a simple segregation of Bromelica from Melica genus is rejected. © 2003 The Linnean Society of London , Botanical Journal of the Linnean Society , 2003, 141, 447 – 463.