Guess what? I went through a lot of my old C&C booklets and in #203 Afghans (1970) there it is big as life. Sorry I can't send you a photo, but here are the instructions for the clusters:

7th rnd: Attach Green to 3rd dc of any petal of previous rnd, ch 3, in same dc where yarn was attached make a 2-dc cluster as follows: HOLDING BACK ON HOOK LAST LOOP OF EACH DC, MAKE 2 DC IN SAME DC, YARN OVER AND DRAW THROUGH ALL LOOPS ON HOOK; ch 2, make 3-dc cluster in same dc, * ch 3, in 3rd dc of next petal make 3-tr cluster, ch 4 3-d tr cluster, ch4 and 3-tr cluster for corner group; ch 3 in 3rd dc of next petal make 3-dc cluster, ch2, 3-dc cluster. Repeat from * around, ending with ch 3. Join to tip of first cluster.


The instructions in caps were originally in italics and constitute a beginning cluster. In most other publications this would actually be called a "beginning 3-dc cluster" rather than a chain and a 2-dc cluster as it is here. I guess that's what happened when they updated the pattern to the instructions that you are using. Too bad they failed to tell you how to do it! The way these old instructions are written is actually a truer description of what is happening, but it's just not the current convention.

Your other clusters are to be done the same way except for the chain substituting for a stitch. You will work make clusters of dcs and trs and d-trs. In each case you hold back on the hook ONLY one loop for each stitch.

So in the treble clusters above, you would wrap the yarn around the hook two times for each tr, but you would work off two loops each stitch time rather than three.

After you have completed all the stitches in the cluster group
you do a yarn-over and pull through all the remaining loops on the hook. This will vary with the number of stitches in the group - NOT with the type of stitch used. In other words there will be four loops to pull through in a cluster of three dcs, or three trs, or three d-trs.

These conventions are applicable to MOST cluster situations, but carefully check your directions in other patterns because they could vary with a designer's whims.