Solitary herb with a very stout tap root, split into a few main branches, yellow when fresh (not on herbarium specimens); a caudex 0.5–1(1.5) cm thick and upper part densely covered with leaf remains, ending in one or more rosettes up to 15–20 cm wide on stout branches. One or several erect, simple flowering stems up to 10–15(–20) cm tall, with several leaves, densely pubescent with white, articulate, floccose hairs. The species of Pedicularis are semi-parasites, partly depending on nutrients from other species through root connections. It is assumed that P. dasyantha is attached to Dryas octopetala in Svalbard.

Leaves alternate. Rosette leaves up to 8–12 cm; petioles constituting up to ½ of the leaf length, narrowly winged; blades oblanceolate to lingulate in outline, pinnatifid to pinnatisect, lobes crenate or shallowly to moderately lobed, sparsely pubescent in the distal part and densely pubescent with long, articulate, floccose hairs towards the stem.

Inflorescence a short, dense, bracteate raceme with 8–15(25) flowers on short pedicels. Lower bracts much longer than flowers, upper bracts shorter than flowers, pinnately divided with broadened mid rib. Petioles of bracts broadly winged and constitute ca. 2/3 of the length of bracts.

Flowers monosymmetric, erect. Calyx fused, tubular, with 5 obtuse to acute teeth, moderately two-lipped, strongly pubescent with long, floccose hairs. Corolla 1.2–2.0 cm, dark purple, pink or nearly white, with a tubular fused part, limb two-lipped with a three-lobed lower lip and a galeate (helmet-shaped) upper lip. The upper lip laterally compressed and with long, floccose hairs. The lower lip 3-lobed with the side lobes broader than the mid lobe, sparsely pubescent especially along the margins. Stamens 4, 2 short and 2 longer. Gynoecium of 2 fused carpels with a single style and a globular stigma. Stamens and stigma not protruding from the corolla tube.

Fruit a one-roomed, falcate capsule, 10–14 × 6–10(11) mm, opening at the top and with many seeds. Seeds have a white and fluffy seed coat that retains water as a sponge.

Sexual reproduction by seeds; no vegetative reproduction. This plant takes many years to reach reproductive age (Odasz-Albrigtsen 1999) but it flowers regularly and seems to be little damaged by bad weather as the flowers are protected by the pubescence. Fruit-set is regular. The flowers are adapted to pollination by flower-specific insects. It has been assumed that the genus Pedicularis is obligately pollinated by bumble-bees (the genus Bombus). No representatives of this insect group are present in Svalbard. It is probable that the main pollinators are flies and it is also probable that many flowers self-pollinate. Seed germination in experiments has been extremely low (0.6 %; Eurola 1972) or not successful, possibly due to lack of host organisms (Alsos et al. 2013; Müller et al. 2011).

The stiff stems and the apical opening of the capsule are adaptations to ballistic dispersal.

The two Svalbard species of Pedicularis – P. dasyantha and P. hirsuta – differ in size (P. dasyantha is larger, especially the flowers), density of pubescence (P. dasyantha is much more hairy), flower shape and pubescence (P. dasyantha has hairy flowers, P. hirsuta glabrous ones), and somewhat in ecology (P. dasyantha usually occupies drier sites than P. hirsuta, but they often grow close to each other). Digging up the plants, the roots of P. dasyantha are distinctly yellow (when fresh), whereas those of P. hirsuta are white or brownish. The seeds of P. dasyantha have a fluffy white seed coat that acts as a sponge to catch rain water, whereas the seeds of P. hirsuta are small and brown.

Most often growing in moderately to densely vegetated heaths, slopes and terraces dominated by Dryas octopetala and Cassiope tetragona. Due to the semi-parasitic behaviour, P. dasyantha always is found close to Dryas and hardly survives in sparsely vegetated environments. On mixed substrates with good or moderate drainage and circumneutral to basic soil reaction (pH). On moderately sheltered to moderately exposed sites, requiring a minimum of snow protection during winter. Probably little grazed by reindeer and geese.

Quite thermopilous. With few exceptions restricted to the middle arctic tundra zone and to the weakly and clearly continental sections. Restricted to Spitsbergen and there only found in the areas with more basic bedrock and substrates from Adventdalen northwards.

General range, see Comments.

Pedicularis dasyantha belongs to a small group of four taxa (see Hultén 1968, 1973; Elven et al. 2011) variously treated as species or as subspecies of one species (of P. lanata, P. kanei or P. alopecuroides). The priority species name in this group seems to be P. alopecuroides if subspecific treatment is preferred. Together these races or species form a nearly circumarctic group with P. dasyantha in Svalbard, Novaya Zemlya and the bordering mainland, and W Taimyr, P. alopecuroides from E Taimyr eastwards to the river Kolyma, P. lanata in NE Asia eastwards from Kolyma and in N North America and Greenland, and P. pallasii in non-arctic parts of the North Pacific regions. Transitions between these four have not yet been confirmed and rank as species is perhaps the most appropriate with the present level of knowledge.

Ivanina (1980) recognized two varieties in P. dasyantha: var. dasyantha in Svalbard, Novaya Zemlya, and the mainland Yugorskiy Peninsula, and var. igoschiniae Ivanina in Polar Ural and Taimyr. This variation has not been independently confirmed.

In the inner Isfjorden area, pale pink colour morphs dominate, whereas darker violet colour morphs dominate in the Kongsfjorden, Woodfjorden and Liefdefjorden areas (Odasz & Savolainen 1996).

Alsos, I.G., Müller, E. & Eidesen, P.B. 2013. Germinating seeds or bulbils in 87 of 113 tested Arctic species indicate potential for ex situ seed bank storage. – Polar Biology 36: 819–830. Doi 10.1007/s00300-013-1307-7.

Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF) Vascular plants. http://panarcticflora.org/

Eurola, S. 1972. Germination of seeds collected in Spitsbergen. – Annales Botanici Fennici 9: 149–159.

Hultén, E. 1968b. Comments on the flora of Alaska and Yukon. – Arkiv för Botanik, ser. 2, 7(1). 147 pp.

Hultén, E. 1973. Supplement to Flora of Alaska and neighboring territories. A study in the flora of Alaska and the transberingian connection. – Botaniska Notiser 126: 459–512.

Ivanina, L.I. 1980. Pedicularis L. – In: Tolmachev, A.I. & Yurtsev, B.A., eds., Flora Arctica URSS. VIII. Geraniaceae–Scrophulariaceae: 293–331.

Müller, E., Cooper, E.J. & Alsos, I.G. 2011. Germinability of arctic plants is high in perceived optimal conditions but low in the field. – Botany 89: 337–348.

Odasz, A.M. & Savolainen, O. 1996. Genetic variation in populations of the arctic perennial Pedicularis dasyantha (Scrophulariaceae), on Svalbard, Norway. – American Journal of Botany 83: 1379–1385.

Odasz-Albrigtsen, A.M. 1999. Den fargerike ullmyrkleggen. Et eksempel på en arktisk diploid plante med begrenset genetisk variasjon. – Norsk Polarinstitutts Meddelelser 150: 85–93.