title: Early reproductive developmental anatomy in Decaisnea (Lardizabalaceae) and its systematic implications.
abstract: OBJECTIVE
  Decaisnea insignis, known as 'dead man's fingers' (Lardizabalaceae), is widely distributed in China and the Himalayan foothill countries. This economically important plant, which is the only species in the genus, has not been the subject of any embryological studies aside from one brief, older paper that lacks micrographs. Data on Decaisnea are also important because its systematic position has been unstable since the genus was established in 1855. Therefore, the objectives of this study were: (a) to use modern microscopy to document early reproductive anatomical development in Decaisnea; and (b) to compare qualitatively these early embryological characters with allied taxa in a systematic context.
  
  
  METHODS
  Decaisnea insignis floral buds and inflorescences were regularly collected from Shaanxi Province, China and prepared for light microscopy. The embryological characters studied were qualitatively compared with those of allied taxa via a thorough examination of the existing literature.
  
  
  RESULTS
  Early reproductive anatomy in Decaisnea was documented and novel revelations made. It was discovered that the pollen is shed when three-celled (not two-celled, as previously reported), and that endosperm formation is nuclear (not cellular or helobial, as previously reported). These two newly revealed embryological characters are not found in any other members of Lardizabalaceae. Furthermore, neither are persistent antipodal cells, which we confirmed to be present in Decaisnea.
  
  
  CONCLUSIONS
  Decaisnea and other Lardizabalaceae characteristically have tetrasporangiate anthers, a secretory tapetum, simultaneous microsporocyte cytokinesis, primarily bitegmic, crassinucellate ovules, and a Polygonum type embryo sac. However, in the family, persistent antipodals, nuclear endosperm, and pollen shed at the three-celled stage are only found in Decaisnea. These embryological data prompted the suggestion that Decaisnea needs elevation above the level of genus.
authors.affiliation: Beijing Urban Ecosystem Research Station, State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China.
authors.forename: Hua-Feng
authors.initials: HF
authors.lastname: Wang
authors.forename: Cynthia Ross
authors.initials: CR
authors.lastname: Friedman
authors.forename: Zhi-Xin
authors.initials: ZX
authors.lastname: Zhu
authors.forename: Hai-Ning
authors.initials: HN
authors.lastname: Qin
mesh_terms: D056625:Endosperm / Q000166:cytology / Q000196:embryology; D056130:Gametogenesis, Plant; D056771:Ovule / Q000166:cytology / Q000196:embryology; D011058:Pollen / Q000166:cytology / Q000196:embryology; D029626:Ranunculaceae / Q000033:anatomy & histology* / Q000145:classification / Q000166:cytology / Q000196:embryology*; D012098:Reproduction