As Michael said, Bronson's version #27 of Child #81 comes from Sharp-Carpeles. Here's that version, which has a number of interesting variants on the standard wording. I think it's clear that the "oil of green" must have come from Mrs. Delie Knuckles, and not from a misunderstanding by Sharp.

Little Musgrave and Lady Barnard, #23 J

1 There was four and twenty ladies there
A-dancing at the ball
The first came in was a lily-white robe,
The next came pink and blue,
The third came in was Lord Banner's wife,
The flower of the view.

2 This little MacGroves a-being there,
All dressed in oil of green,
He looked at her, she looked at him,
The like was never seen.

3 She said to him : My sweet MacGroves,
Go home with me to-night;
There's waiting-boys plenty there,
And I'll ride by your side.

4 O no, O no, I dare not go,
I dare not for my life;
I know by the ring you wear
You are Lord Banner's wife.

5 O if I am Lord Banner's wife,
Lord Banner's hain't at home;
Lord Banner he's Redemption gone,
He's on Queen Anna's throne.

6 This little foot-page a-being there,
Determined Lord Banner should know.
He turned his course to Lord Banner's hall
And dingled on the ring.

7 What news, what news, my little foot-page ?
What news are you bringing to me ?
Is any of my fine brick castles blown down,
Or any of my men false been ?

8 There's none of your fine brick castles blown down,
Nor none of your men false been,
But little MacGroves in fair Scotland
In bed with your lady.

9 O if this be a lie your telling to me,
As O I take it to be,
I'll build me a gallows in fair Scotland,
And hanged you shall be.

10 If this be a lie I'm telling to you,
As O you take it to be,
You need not build no gallows at all,
Just hang me on a tree.

11 In calling all his merry men,
By one, by two, by threes,
Saying: Let's all go to fair Scotland
This young MacGroves to slay.

12 Then one of Lord Banner's foremost men
Who wished MacGroves no ill,
He drew his horn and he blew it loud,
He blew it loud and thrill.

13 What's this I hear, says little MacGroves,
It blew so loud and clear.
I think it's Lord Banner's horn.
O him how do I fear.

14 Lie down, lie down, my sweet MacGroves,
And keep me from the cold;
It's nothing but my father's horn
Calling the sheep to the fold.

15 They lay and slept, they slumbered and slept,
So sweetly they did sleep;
But when they woke who did they spy,
Lord Banner's at their feet.

16 Says : How do you like my own bedside ?
Or how do you like my sheet ?
Or how do you like my gay young wife
Lies in your arms asleep ?

17 Very well I like your own bedside,
Much better I like your sheet,
But the best of all's your gay young wife
Lies in my arms asleep.

18 Rise up, rise up, you young MacGroves,
Rise up, draw on your clothes.
It shall never be said in the fair Scotland
I slain a naked man.

19 O no, O no, I dare not rise,
I dare not for my life,
For you have two big, new, keen swords,
I have ne'er a knife.

20 O if I have two new, keen swords,
They cost deep in purse,
And you can take the best of them
And I will take the worst.

21 You can strike the very first blow,
But strike it like a man;
And I will strike the second blow;
I'll kill you if I can.

22 The very first lick that MacGroves struck,
He wounded Lord Banner full sore;
The second lick Lord Banner struck, -
MacGrove he spoke no more.

23 Rise up, rise up, my gay young wife,
Rise up, draw on your clothes,
And tell to me which you like best,
I or this young MacGroves.

24 If you lay struggling in your blood
As MacGroves he does now,
I'd kiss the lips of sweet MacGroves,
But I never would kiss yours.

From Sharp/Karpeles, English Folk Songs from the Southern Appalachians, Volume 1, page 175, #23 J, Sung by Mrs. Delie Knuckles at Barbourville, Knox County, Kentucky, May 16, 1917