After fertilization the female cell, now called the oospore, divides and part of it develops into the embryo (new sporophyte), which remains dormant for a time still protected by the ovule which has developed to become the seed.
The name expresses the most universal character of the class, the importance of which was first noticed by John Ray, namely, the presence of a pair of seed-leaves or cotyledons, in the plantlet or embryo contained in the seed.
Cuscuta has a thread-like, spirally twisted embryo with no trace of cotyledons.
The seeds are filled with the large embryo, the two cotyledons of which are variously folded.
It is absurd to call the larva of a newt or of a Caecilian a tadpole, nor is the free-swimming embryo of a frog as it leaves the egg a tadpole.