Abstract: In order to discuss the invasiveness of Ph.americana,an anatomical study was conducted on the different development stages of the Ph.americana flowers organs by the common plant paraffin section. The results showed that the ovule of Ph.americana was grown near the axis on the inside of carpel and belongs to a typical basal placentation,pour ovule,double integument,thick bead heart type.The secondary sporogenous cells developed into a megaspore mother cells.Megaspore mother cells meiosis developed into three megaspore,the whole point of the megaspore development for embryo sac,and embryo sac was contents type.The meiosis of microspore mother cells was the same time type,a tetrad tetrahedron form arrangement,and mature pollen was 2-cell type.It was higher similarity with native species that might be adapted to habitat.

Key words: Invasiveness, Ph.americana, Megaspore, Microspore, Female gametophyte, Male gametophyte

CLC Number: 

• Q944.58