title: Comparative anatomy, morphology, and molecular phylogenetics of the African genus Satanocrater (Acanthaceae).
abstract: OBJECTIVE
  Anatomical and morphological features of Satanocrater were studied to test hypotheses of xeric adaptations in the genus, which is endemic to arid tropical Africa. These features, together with molecular data, were used to test the phylogenetic placement of Satanocrater within the large plant family Acanthaceae.
  
  
  METHODS
  We undertook a comparative study of four species of Satanocrater. Carbon isotope ratios were generated to test a hypothesis of C(4) photosynthesis. Molecular data from chloroplast (trnG-trnS, trnG-trnR, psbA-trnH) and nuclear (Eif3E) loci were used to test the placement of Satanocrater within Acanthaceae.
  
  
  RESULTS
  Anatomical features reflecting xeric adaptations of species of Satanocrater included a thick-walled epidermis, thick cuticle, abundant trichomes and glandular scales, stomata overarched by subsidiary cells, tightly packed mesophyll cells, and well-developed palisade parenchyma on both leaf surfaces. Although two species had enlarged bundle sheath cells, a feature often implicated in C(4) photosynthesis, isotope ratios indicated all species of Satanocrater use the C(3) pathway. Molecular data resolved Satanocrater within tribe Ruellieae with strong support. Within Ruellieae, our data suggest that pollen morphology of Satanocrater may represent an intermediate stage in a transition series.
  
  
  CONCLUSIONS
  Anatomical and morphological features of Satanocrater reflect adaptation to xeric environments and add new information about the biology of xerophytes. Morphological and molecular data place Satanocrater in the tribe Ruellieae with confidence. This study adds to our capacity to test hypotheses of broad evolutionary and ecological interest in a diverse and important family of flowering plants.
authors.affiliation: Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California 91711, USA. etripp@rsabg.org
authors.forename: Erin A
authors.initials: EA
authors.lastname: Tripp
authors.forename: Siti
authors.initials: S
authors.lastname: Fatimah
mesh_terms: D027901:Acanthaceae / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D000222:Adaptation, Physiological / Q000235:genetics; D000349:Africa; D002467:Cell Nucleus / Q000235:genetics*; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D003889:Desert Climate; D019143:Evolution, Molecular; D061125:Genes, Chloroplast / Q000235:genetics*; D014644:Genetic Variation; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics; D010802:Phylogeny; D019441:Plant Epidermis / Q000033:anatomy & histology / Q000235:genetics / Q000648:ultrastructure; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics*; D054046:Plant Stomata / Q000033:anatomy & histology / Q000235:genetics / Q000648:ultrastructure; D011058:Pollen / Q000033:anatomy & histology / Q000235:genetics / Q000648:ultrastructure; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins