Draba norvegica

Tracheophyta MagnoliopsidaCruciferaeDrabaDraba norvegica

Ecology

A perennial tufted herb of base-rich rocks, occurring on rock ledges, in crevices in cliffs, on consolidated scree and in other bare places. Upland, from 310 m in Glendhu Forest (W. Sutherland) to 1160 m on Ben Lawers (Mid Perth), and more frequent at the higher end of that range.

Status

Native

World Distribution

European Arctic-montane element, but absent from mountains of C. Europe; also in N. America.

Broad Habitats

Light (Ellenberg): 8

Moisture (Ellenberg): 5

Reaction (Ellenberg): 7

Nitrogen (Ellenberg): 3

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 0.6

July Mean Temperature (Celsius): 11.2

Annual Precipitation (mm): 2311

Height (cm): 5

Perennation - primary

Perennial

Life Form - primary

Chamaephyte

Woodiness

Herbaceous

Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 33

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: 0

JNCC Designations

NBNSYS0000002864

Scarce Atlas Account

Scarce Atlas Account: 

Draba norvegica Gunnerus

Rock whitlowgrass

Status: scarce

 

 

This is a rare, densely tufted plant of lime-rich rocks, where its preferred habitat is rock ledges and crevices of steep faces, consolidated scree and similar bare places. D. norvegica grows on calcareous mica-schists of the Dalradian and Moine series, hornblende schist, Lewisian gneiss and Old Red Sandstone. Frequent associates are Alchemilla alpina, Carex atrata, C. capillaris, Cerastium alpinum, Festuca ovina, Minuartia sedoides, Poa alpina, Salix reticulata, Saxifraga nivalis, S. oppositifolia and Silene acaulis, though it occurs in heterogeneous rock face communities rather than readily recognisable types. It is known from as low as 500 metres in Sutherland but is more frequently recorded at higher altitudes, reaches 1210 metres near the summit of Ben Lawers.

D. norvegica is a perennial, flowering in July. It is usually self-pollinated and sets abundant seed.

At present it appears to be under little threat, but collecting would certainly affect the mostly small populations. A number of new colonies have been discovered in Scotland in recent years, suggesting that it is probably under-recorded.

This is an arctic-subarctic species with a widespread distribution, occurring westwards to the Hudson Bay area of Canada and eastwards to northern Russia. In Scotland it is at its southern limit in Europe. 

Scottish plants show little character variation, but elsewhere variability is appreciable. Plants similar to those from Scotland are known from various parts of Scandinavia, and have been described as a separate species, D. rupestris. It is more likely, however, that all are members of a widespread Arctic complex. Hybridisation with D. incana is thought to occur, and apparent intermediates grow in Strath Carron.

 

 

M. J. Y Foley

Atlas text references

Atlas (43a)
Corner RWM
1999.  Observations on a low altitude site for Draba norvegica and Poa glauca in West Sutherland v.c. 108. Botanical Journal of Scotland. 51:127-129.
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1996)
Rich TCG
1991.  Crucifers of Great Britain and Ireland. Botanical Society of the British Isles Handbook no. 6.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.