Answer: Ground pine or Lycopodium obscurum requires a damp, acidic soil and grows wild; it is rarely seen in gardens or sold commercially. (I don't think I have ever seen it for sale any where.) To be sure this is the same plant you have in mind, here is a photo.
The ground beneath the Leyland cypresses is usually fairly dry due to their overhanging branches and extensive root systems. You might try a shade tolerant groundcover that will also grow in drier soil such as Ajuga reptans, Vinca minor, or when they are quite large and the area is thoroughly shaded at the base, Epimedium. Your local professional nursery staff may have additional suggestions based on a more detailed understanding of the growing conditions where you would be planting, and your design goals.
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