as.data.frame.character lacks nm= argument

Is the following behavior with as.data.frame(nm=...) a bug?  It is an inconsistency:

as.data.frame(LETTERS[1:10], nm="FirstTenLetters")

Error in as.data.frame.vector(x, ..., nm = nm) : 
  formal argument "nm" matched by multiple actual arguments

nm= works for integer arguments:

as.data.frame(1:10, nm="OneToTen")

OneToTen
1         1
2         2
3         3
4         4
5         5
6         6
7         7
8         8
9         9
10       10

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com