In $Pteris$,the sori are

The circinate venation is the characteristic feature of ferns. It refers to

Heterospory and seed habit are exhibited by a plant possessing

In $Dryopteris$,the placenta is the site of attachment for:

From an evolutionary point of view,the retention of the female gametophyte with the developing young embryo on the parent sporophyte for some time is first observed in:

In Pteridophytes,how are the sporophylls arranged?