title: [Studies on the pollen morphology of ten species of  Achillea].
abstract: OBJECTIVE
  To study the pollen morphology of ten species of Achillea.
  
  
  METHODS
  The pollen morphology of ten species of Achillea was examined with LM and SEM.
  
  
  RESULTS
  The pollen grains were usually 3-colporate, subspheroidal. The exine ornamentation consisted of verrucate, spinulate and foveolate. But some differences in size, colpae and exine ornamentation were found.
  
  
  CONCLUSIONS
  The slight differences of the pollen morphology are useful to some extent for the classification of the ten species of Achillea.
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100083, China.
authors.forename: Yan-fang
authors.initials: YF
authors.lastname: Yang
authors.forename: Tie-ming
authors.initials: TM
authors.lastname: Ai
mesh_terms: D031162:Achillea / Q000145:classification / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D011058:Pollen / Q000648:ultrastructure*; D013045:Species Specificity