This is a maximum card with the "Dia de la Madre" (Mother's Day) stamp from Argentina that was issued on October 17, 1959. The card is the size of a standard size postcard, but it has a blank back and is rather thin cardstock. In Argentina, Mother's Day is the third Sunday in October.
There is part of a poem printed in Spanish on the card. The Google translation didn't make much sense to me, and I couldn't find a better translation. Following are translations of other words on the card.
Dia de Emision
Day of Issue
I am participating in Sunday Stamps at Viridian's Postcard Blog