© Copyright: Images: Jouko Lehmuskallio. Wite arctic whitlow grass photographed in Canada. All rights reserved.
Snow Whitlow Grass
- Name also: Snow Whitlowgrass, Snow Whitlow-grass
- Family: Mustard Family – Brassicaceae (Cruciferae)
- Growing form: Perennial herb. Tufted.
- Height: 3–10 cm (1.2–4 in.). Stem thin, grey-haired (stellate-haired, lacking straight hairs), usually leafless.
- Flower: Corolla regular (actinomorphic), white, approx. 5 mm (0.2 in.) wide; petals 4, entire, 2–3 mm (0.08–0.12 in.) long. Sepals 4. Stamens 6, of which 4 long and 2 short. Gynoeciem fused, a single carpel. Inflorescence a 2–10-flowered short-stemmed (2–3 cm (0.8–1.2 in.)) cluster, which grows into a long-stemmed (10 cm (4 in.)) raceme.
- Leaves: In dense basal rosette, stem leaves possible. Blade stalkless, elliptic–obovate, 5–10 mm (0.2–0.4 cm) long, with glossy margins, densely stellate-haired, which gives the leaves the gray colour that is characteristic of the species.
- Fruit: Many-seeded, lanceolate, quite flat, glabrous, 7–9 mm (0.28–0.36 in.) long, short-stalked, erect silicula terminated by a short bristle.
- Habitat: Fell gravels, mountain aven heaths and crevices. Requires alkaline soil (is calciphile).
- Flowering time: June–July.
- Endangerment: Vulnerable.
Indentifying genus draba plants is regarded as a tricky business, and this is certainly true of the fell species. The white-flowered, basal rosetted members of the genus are the most difficult of all and demand the closest of studies. As well as snow whitlow grass, species that belong to this most difficult group include rock whitlow grass (D. norvegica), white arctic whitlow grass (arctic draba, Austrian draba, D. fladnizensis), Lapland whitlow grass (D. lactea), smooth draba (D. daurica) and gray-leaved whitlow grass (D. cinerea), which has yellowish white flowers and is found around the eastern border of Kuusamo and Salla, could also be included in the group.
Like other members of the genus that grow in the north-western ”arm” of Finland, snow whitlow grass, which demands calcium-rich soil, is very rare in Finland. The species’s habitats are limited to the large fells of Enontekiö in pretty much the same way as Arctic draba and Lapland whitlow grass. Rock whitlow grass and scree whitlow grass can be found growing further to the south. Perhaps the easiest way to tell snow whitlow grass is by the grey colour that its stellate hairs give it. Snow whitlow grass has only stellate hairs (meaning that the hair is branched in many different directions). Rock whitlow grass and Lapland whitlow grass have stellate, forked and straight hairs, scree whitlow grass has stellate and straight hairs, and Arctic draba has virtually only stellate hairs. When it is considered that some members of the genus can cross-breed with each other (at least snow whitlow grass and Lapland whitlow grass), there are plenty challenges even for an experienced botanist – botanists in the future should not only make sure they have a plant book that specializes in hairs but also a DNA reader or hair recognizer.
White Arctic Whitlow Grass
Name also Arctic draba, Austrian draba. NOT TRANSLATED YET. Tunturikynsimö kasvaa samoilla paikoilla lumikynsimön kanssa ja on hyvin samannäköinen. Erojakin on; tunturikynsimön varsi on yleensä ainakin yksilehtinen ja kalju (lumikynsimön yleensä lehdetön ja tähtikarvainen). Myös ruusukelehdet ovat hapsikarvaisia (lumikynsimöllä tähtikarvaisia). Tunturikynsimön lidut ovat lyhyempiä (4–6 mm, lumikynsimön 7–9 mm) ja usein sinipunaisia, niin kuin varsikin.