What's the difference between hummock and hummocky?

Hummock

Definition:

(n.) A rounded knoll or hillock; a rise of ground of no great extent, above a level surface.
(n.) A ridge or pile of ice on an ice field.
(n.) Timbered land. See Hammock.

Example Sentences:

(1) He wondered what had happened to the land, its fish-filled inlets, the shrimp-spawning marsh, the oak groves, the hummocks overrun with white egrets, how a place that fed so richly whoever sailed through it could dissolve, history and graveyard and church and road and home.
(2) Reaching an open area of sparse trees beside the track, we set off across a large clearing of soft hummocks.
(3) Highest densities were located on the sloping banks of hummocks, ponds and potholes.

Definition:

Example Sentences:

(1) Three bacterial isolates, a Pseudomonas sp., a Bacillus sp., and an Arthrobacter sp., commonly isolated from a hummocky sedge-moss meadow at Devon Island, N.W.T., Canada, were selected for further taxonomic characterization and for a study of the effects of temperature and limiting carbon source on growth.
(2) Three species of arborescent bryozoans share a bias in growth rate that favors reverser branches (those whose direction of growth is opposite that of their parent branch); this bias produces a common hummocky appearance to the top margin of the colony.
(3) Simulations based on the distinction between reversing and nonreversing branches reproduce the hummocky pattern, but offer little insight into the underlying mechanism.