Portuguese Knotted Stem Stitch

I'm working on the second embroidery in my elements series, Earth, which is lots of strong lines on a handmade green and brown felt background.

I've been enjoying looking up stitches in my lovely new-to-me 1946 edition of Mary Thomas's Dictionary of Embroidery Stitches which I bought for £5 in Stratford over Easter. Discovering new stitches is very satisfying.

This evening, I picked out Portuguese Knotted Stem Stitch, which takes a bit of thinking, but is very attractive when worked in cotton Perle. It is the green line in the photo, with some square chain stitch above and knotted chain stitch below.