The Phylogenetic Significance Of Plant Micromorphological And Anatomical Features Of The Family Saxifragaceae In Northeastern China

The morphological and anatomical structures of the leaves,fruits and seeds of Saxifragaceae taxa(including 27 species and 3 varieties placed in 11 genera)in northeastern China were deeply studied in this paper using the morphological observation and GMA method.The results showed that the Saxifragaceae taxa in northeastern China could be divided into two groups: Saxifragaceae(including Saxifragoideae sensu lato and Hydrangeoideae)and Ribesiaceae.Saxifragaceae subfamily Saxifragoideae sensu lato(Parnassioideae,Ribesioideae,Saxifragoideae):In the subfamily the leaf epidermis are with multiseriate hairs,uniserial glandular hairs or multiseriate glandular hairs.The petioles are traingular,heart-shaped or round in transversal sections and with 1,3 or 5 vascular bundles which are arranged in V shape.Fruits have two carpels and the endocarp is composed one or several layers of cells which are not lignified or slightly lignified(except Astilbe).The seeds are ovoid and testas glabrate,with small projections or ribs.Saxifragaceae subfamily Parnassioideae: Trichomes are absent in the subfamily,fruits have 4 carpels and endocarps are composed of one layer of highly lignified cells.The seeds are ovoid and testas with projections.Trichomes are absent in the sunfamily Ribesioideae.The petioles are traingular in transversal sections and with one vascular bundle.Fruits have 5-6 carpels and the endocarps are composed one layer of highly lignified cells.: The leaves in Hydrangeoideae are with single celled hairs or multicellular hairs.The petioles are heart-shaped in transversal sections and with 1,3 or5 vascular bundles which are arranged in V shape.Fruits have 2,3 or 5 carpels.The endocarps are composed of several layers of highly lignified cells,seeds are spindle in shape and testas are with reticular grain.Ribesiaceae: The leaves have no hairs or with unicellular hairs.The petioles are heart-shaped in transversal sections and with 3 vascular bundles arranged in V shape which have fibers.The pith cavities are present in the petioles and tannin occurs in the parenchyma cells.Seeds are ovoid and out layer of cells are columnar.The study improved the morphological study of the family Saxifragaceae innortheastern China,provided the morphological evidence for that the molecular systematics.Our study showed that the micromorphological and anatomical structures of the plants have important value for the systematical study of the family and provided the morphological bases for the further phylogenetic study of Saxifragaceae in China.