Using mutate_() within a higher function to make a match across two tables

Question

I have the following code, which works when I run it on its own:

library(tibble)
library(dplyr)

mytable <- tibble(Subgroup = c("C", "C", "A", "C"),
                                Category = c("A", "B", "D", "D"))

color_table <- tibble(Subgroup = c("A", "B", "C", "D"),
                                colors = c("#0079c0", "#cc9900", "#252525", "#c5120e"))

(mytable <- mutate(mytable, colors = color_table[[2]][match(mytable[[2]], color_table[[1]])]))

# A tibble: 4 × 3
   Subgroup Category  colors
      <chr>    <chr>   <chr>
1        C        A #0079c0
2        C        B #cc9900
3        A        D #c5120e
4        C        D #c5120e

I now want to include this code into a higher function. I'm trying here with mutate_():

(mytable <- mutate_(mytable, .dots = list(colors = color_table[[2]][match(mytable[[2]], color_table[[Subgroup]])])))

# A tibble: 4 × 3
   Subgroup Category  colors
      <chr>    <chr>   <chr>
1        C        A      NA
2        C        B      NA
3        A        D      NA
4        C        D      NA

It's appending the colors variable, but it's not doing the matching correctly. Any tips on how I should adjust?