There are multiple reasons. 1) there are similar fossils found on different continents. 2) the continents shapes show that they could easily fit together. 3) there are similar rocks, minerals,and land forms on different continents. 4) there's evidence that there was once lush vegetation in areas with extreme cold.
This type of asexual reproduction is called apomixis.
Apoximis is reproduction by special generative tissues without fertilization. It includes parthenogenesis in animals, in which the new individuals develop from unfertilized egg, and apogamy in certain plants in which the generative tissues may be the sporophyte or the gametophyte.
