Nuclear DNA C-values Complete Familial Representation in Gymnosperms

The gymnosperms are a monophyletic yet diverse group of woody trees with approx. 730 extant species in 17 families. A recent survey showed that DNA C-values were available for approx. 16 % of species, but for only 12 of the 17 families. This paper completes familial representation reporting rst C-values for the ve remaining families: Boweniaceae, Stangeriaceae, Welwitschiaceae, Cephalotaxaceae and Sciadopityaceae. C-values for nine Ephedra and two Gnetum species are also reported. C-values are now available for 152 (21 %) species. Analysis conrms that gymnosperms are characterized by larger C-values than angiosperms (modal 1C of gymnosperms 15 . 8 pg compared with 0 . 6 pg in angiosperms) although the range (1C 2 . 2532 . 20 pg) is smaller than that in angiosperms (1C 0 . 05 127 . 4 pg). Given complete familial coverage for C-values and increasing consensus in gymnosperm phylogeny, the phylogenetic component of C-value variation was also investigated by comparing the two datasets. This analysis revealed that ancestral gymnosperms (represented by cycads and/or Ginkgo; mean genome size 14 . 71 pg) probably had larger genomes than ancestral angiosperms.