Sagina subulata 

Scotch moss is a prostrate herbaceous evergreen perennial that's actually part of the carnation family (Caryophyllaceae) but it superficially resemble moss. It's a flowering plant that thrives in full sun to partial shade rather than the moist, shady conditions where true mosses are found (mosses are primitive, non-flowering plants). The common name Irish moss generally refers to plants with emerald-green leaves while Scotch moss is generally used for cultivars with gold to chartreuse foliage. The species most commonly offered commercially is Sagina subulata, a native of western and central Europe that is hardy in zones 4-8. 

Plant Scotch moss in shady or part shady areas as a ground cover. Plants arrive in a gallon-size pot and spread slowly over time. Its recommended to plant each plant about 12" apart if you expect them to fill in as a ground cover quickly.

Arrives to you in a quart sized pot pot.