on nodes

Eric sent out a remark on my Mercury post:

Just a quick semantic node or correction...  Mercury is also above the plane of its descending node, as well as its ascending node.  The two nodes, connected to the Sun and the Earth represent four points on the plane of the Ecliptic.  When Mercury passes through that plane in a northerly direction, it's passing through the ascending node.  Southerly, descending.  As long as the planet is above either of those nodes, and it is elongated to the east of the Sun, it is a nominally favourable evening object.  Some days after the ascending node is passed, or some days before the descending node is passed, same difference.

I'm not sure what he means exactly. Are there two ascending node points in an orbit? Is he getting at that there are two planes? Ours vs. the plane of Mercury's canted orbit?