Abhijnaana Sakuntalam.

Courtesy: Sri.PK.Ramakrishnan

This is the name of the nataka authored by Kalidasa. It is based on the story of 
Sakuntala given in Mahabharata. Kalidasa has added the adjective abhijnaana taken from Ramayana. When Hanuman meets Sita he gives her the ring - anguliyakam -
as an identification that he is the messenger of Rama. Then Sita gives him the
chudamani to be given to Rama to confirm that Hanuman had met Sita. 
 
Sundara Kanda Sarga 38 Sloka 1o
 
Hanuman tells Sita -
 
yadi notsahase yaatum mayaa saardham anindite /
abhijnaanam prayaccha tvam jaaniyaat raaghavo hi yat //
 
Sundara Kanda Sarga 39 Sloka 1 and 2
 
manim datvaa tata: sitaa hanumantamathaabraviit /
abhijnaanam abhijnaatam etadraamaaya tatvata: //
manim tu drishtvaa raamo vai trayaanaam samsmarishyati /
viiro jananyaa mama cha raajno dasarathaya cha //
 
Kalidasa has adopted this idea in Abhijnaana Sakuntalam. Dushyanta had given a ring to Sakuntala when they met. This ring was lost by Sakuntala in river while 
proceeding to meet Dushyanta who had forgotten his meeting Sakuntala. Later 
a fisherman gets the ring swallowed by a fish. When Dushyanta sees the ring shown to him by the fisherman he remembers Sakuntala.