Woodlands may support an understory of shrubs and herbaceous plants including grasses. Many trees, shrubs, vines, ferns and other herbaceous perennials form clonal colonies naturally. Shrubland is dominated by woody or herbaceous shrubs. The vegetation in this harsh alpine zone consists of herbaceous and shrubby subalpine meadows. It contains about 250 species of annual and perennial herbaceous or semi-woody flowering plants. The understory also contains a wide variety of herbaceous and shrub species. A marsh is a wetland that is dominated by herbaceous rather than woody plant species. They are herbaceous plants or small shrubs. Rosaceae can be trees, shrubs, or herbaceous plants. Primula is a genus of mainly herbaceous flowering plants in the family Primulaceae. The understory is primarily native bunchgrasses with a mix of other cacti and herbaceous species. A scrub-like shrub and herbaceous layer occurs. Echinacea is a genus, or group of herbaceous flowering plants in the daisy family. Grassland is dominated by grass and other herbaceous plants. Six types of flower are generally distinguished in cultivars of herbaceous peonies.