union of a list of logical values

Dear all,
How can I obtain the union of a list of logical values?

Consider the following:
x <- head(iris)
x[,c(2,4)] <- NA
x[c(2,4),] <- NA
# > x
# Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1          5.1          NA          1.4          NA  setosa
# 2           NA          NA           NA          NA    <NA>
# 3          4.7          NA          1.3          NA  setosa
# 4           NA          NA           NA          NA    <NA>
# 5          5.0          NA          1.4          NA  setosa
# 6          5.4          NA          1.7          NA  setosa
z <- data.frame(!is.na(x))
# > z
# Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1         TRUE       FALSE         TRUE       FALSE    TRUE
# 2        FALSE       FALSE        FALSE       FALSE   FALSE
# 3         TRUE       FALSE         TRUE       FALSE    TRUE
# 4        FALSE       FALSE        FALSE       FALSE   FALSE
# 5         TRUE       FALSE         TRUE       FALSE    TRUE
# 6         TRUE       FALSE         TRUE       FALSE    TRUE

I did find a solution, but it seems more like a hack:

##union of logical values by rows (union of list of logical values)
as.logical(rowSums(z))

[1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE

##union of logical values by columns
as.logical(colSums(z))

[1]  TRUE FALSE  TRUE FALSE  TRUE

Another unusable monstrosity is as follows:

##union of list of logical values
z[[1]] | z[[2]] | z[[3]] | z[[4]] | z[[5]]

[1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE

Is there a more elegant way to approach this problem and obtain the
above logical vectors? Regards,
Liviu