Perennial of the Brassicaceae family, native to the mountains of western North America, from the Rockies to the Sierra Nevada and coastal ranges, where it occupies scree, rocks, and alpine meadows on various substrates, between 2,500 and 4,000 meters altitude.
It forms a tight, bright green cushion, remarkably compact and hemispherical, composed of numerous small densely interwoven rosettes — this is precisely what the name densifolia conveys. The leaves are very short, narrow, rigid, and ciliate on the edges, a bright green without a marked grayish indumentum, which gives the cushion a noticeably brighter color than many other species of the genus.
The flowers, a bright yellow with four well-developed and slightly notched petals, are borne on slender, elongated stems 5 to 10 cm tall, which rise above the cushion in an airy manner, in loose clusters of only a few flowers. This contrast between the compactness of the foliage and the lightness of the floral stems is one of the most charming features of the species.
In its natural habitat, flowering extends from June to August depending on altitude. In cultivation, it generally occurs in May-June.
It requires full sun, very strict drainage, and a poor mineral substrate. Delicate to maintain in lowland areas, it is more suited to pot culture, alpine troughs, or very well-drained rock gardens, sheltered from excessive winter moisture.