This is the other noteworthy stitch I used in the baby bonnet. It was taken from Traditional Edgings to Crochet (Dover Needlework Series), which is a collection of vintage edging patterns that are now out of print. I think it's a really handy book to have on hand.
This stitch is the basis for a lovely edging in Ms. Weiss' book (number 1809) worked in size 30-70 crochet cotton. Worked with number 10 bedspread cotton, the pattern makes an edging that is too large for my purposes and is clearly not as delicate as it ought to be. Using just the first row of the pattern topped with a row of single crochet interspersed with ch-3 picots worked very nicely. In any case, this stitch was a fun one. While it isn't really suitable for making a fabric, I think I will use it in edgings and beadings in the future.
Ch a multiple of 6 plus 1.
Work one row of single crochet. Ch4, turn.
Working in the first sc from the beg of the row, work 1 tr. Sk 2, make a 3-tr cluster in the next sc (work 3 tr in same st, holding back final loop of each, yo, pull through all loops on hook), ch5. In the same sc, make a 3-tr cluster, but do not finish it. Once the three trebles have been begun, sk 2 and work an additional tr in third sc from hook, yo, and pull through all loops on hook (joint cluster made). *Sk 2, 3-tr cluster in next sc, ch5, joint cluster in same sc, rep from * across.