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Smooth Draba

Draba daurica

  • Family: Mustard Family – Brassicaceae (Cruciferae)
  • Growing form: Perennial herb. Loosely tufted.
  • Height: 10–30 cm (4–12 in.). Stem unbranched, slightly curved, 1–4-leaved, almost only stellate-haired, upper part almost glabrous.
  • Flower: Corolla regular (actinomorphic), yellowish white, approx. 0.5–1 cm (0.2–0.4 in.) wide; petals 4, entire, approx. 4 mm (0.16 in.) long. Sepals 4. Stamens 6, of which 4 long and 2 short. Gynoeciem fused, a single carpel. Inflorescence a raceme.
  • Leaves: Dense basal rosette and alternate on stem, almost stalkless. Rosette leaves elliptic–lanceolate, usually toothed, with stellate hairs and (sparsely) straight hairs.
  • Fruit: Many-seeded, lanceolate, flat, often alternate, glabrous (sometimes sparsely hairy), 7–12 mm (0.28–0.48 in) long silicula. Stalk quite erect.
  • Habitat: Lappish rock faces in fell tundra, rock shelves, gravels. Forest belt ravines, embankments, river banks, sometimes village meadows. Calciphile.
  • Flowering time: June–July.

Genus Draba is large and dificult. It contains at least 300 species, commonly known as whitlow-grasses, and differentiating between them is like splitting hairs: different kinds of hair or a lack of it, and divisions and numbers are important identification markers.

Smooth draba grows rarely among rocky outcrops and gravels on the fell tundra of Enontekiö and Inari Lapland. In northern Finland it can also be found along river banks, e.g. among the coastal rocks of Kitinen. In Utsjoki and Koillismaa there are also stands on the rock walls of canyons. Smooth draba is larger than a lot of its relatives, its stem is stellate-haired (the upper part is often glabrous) and it is 1–4-leaved. Most of the species’s leaves are in its basal rosette. They are sparsely toothed and quite densely stellate-haired, and they also have a fair proportion of straight hairs. Rock whitlow grass (D. norvegica), which looks a lot like smooth draba, has all the kinds of hairs on its stems (stellate, forked and straight) while the leaves are predominantly straight-haired. Smooth draba looks especially like the rare and protected species gray-leaved whitlow grass (D. cinerea), and a close examination of the hairs is needed to differentiate between the two: on grayleaf draba the whole shoot from the basal rosette to the fruits is densely stellate-haired (there may be a small proportion of forked and straight hairs, while smooth draba is glabrous at the top of the stem or only sparsely haired. Grayleaf draba only grows on rock walls in the canyons of Koillismaa in a total of ten places in Kuusamo and Salla.

Other species from the same genus
Other species from the same family

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