The cardigan is knit in two colors with a third color for the edging. In the pattern example, pale grey and black are used with a red edging.

From the Wool Gathering description, Meg says -

Dear Knitter,

My ma’s Norwegian Tree design, a black and white pullover with red trim, originally appeared on the cover of McCall’s magazine in 1959. Elizabeth’s initial sketch, plus Joan Schrouder’s adaptation from McCall’s were shown on page 87 of EZ’s book, The Opinionated Knitter. A subsequent slew of knitters’ requests for instructions led to this WG.

The original model is a basic circular dropped-shoulder construction, knitted from lower edge to shoulder and cuffs to upper arm. The depth of the sleeve top is measured and marked against the finished body; armholes are machine-stitched and cut, and the sleeves sewn in from the “right” side. The prototype had a straight stand-up boat neck added; Joan made a shaped crew neck.

For the cardigan version on the cover, I substituted pale grey for the original white, added a center front steek, and a slightly modified drop-shoulder. The sleeves were knitted from armhole to cuff.

For more information, see: http://www.schoolhousepress.com/woolgathering.htm