It will help others take a look at the handwriting with the location posted:

Casey English
Estimated Birth Year: abt 1855
Age in 1870: 15
BirthPlace: South Carolina
Home in 1870: Plowdens Mill, Clarendon, South Carolina
Family and Neighbors: View Results
Race: Colored
Gender: Male
Post Office: Manning

It looks like **ena - but I am not good with handwrting. Hopefully someone else here will take a stab at it

In 1880 there is a Lena Francis married the correct age - the index has her listed as Leno:

Name: Leno Frances
Home in 1880: Plowdens Mill, Clarendon, South Carolina
Age: 22
Estimated Birth Year: abt 1858
BirthPlace: South Carolina
Relation to head-of-household: Wife
Spouses's Name: March
Father's birthplace: SC
Mother's birthplace: SC

Have you checked for marriage records?

Denise