In order to add Dracocephalum ruyschiana to the identification key of the genus in Flora iberica (Morales 2010) and thereby facilitating further identification an identification key is provided to distinguish between these two species:

Morphology.-The descriptive terminology follows Morales (2010) and Heywood (1972) and is based on the collected material in the Aran Valley (BC 983298, BC 983299).

Perennial, suffruticose, up to 50 cm (Fig. 1a). Stems ± woody at the base, erect, with short hairs, retrorse or applied. Leaves sessile or subsessile, 14-50 × 1-4 mm, linear to lanceolate, obtuse, ± revolute, with marked midrib, short hairy on margin, the reduced axillary shoots with narrower leaves (Fig. 1b, c). Inflorescence 3.5-6 cm, formed by verticillasters ± close, the lower sometimes distant, with 4-6 flowers each. Bracts ovate-lanceolate or lanceolate, ± acuminate, 11-30 mm, with marked midrib, ciliated at margins; bracteoles ovate-lanceolate or lanceolate, ± acuminate, 4-10 mm (Fig. 1c). Flowers with pedicel of 1-2 mm. Calyx 7-12 mm, tubular, densely pubescent; upper center tooth 5-7 × 3 mm, broad, rounded on top, acuminate, densely pubescent, upper lateral teeth and lower teeth 5-6 × 1 mm, fine, acute, densely pubescent, all reticulated (Fig. 1d). Corolla 21-28 mm, ± conical, violet-blue color, pubescent outside, lanate within only on upper lip; upper lip 5-7 cm, lower lip with 3 lobes, the central one larger, whitish with blue spots in the middle. Stamens included (but some exerted in preserved specimens), inserted more than 10 mm above base of corolla; ± hairy filaments specially at the base; anthers with cottony hairs, with the theca separated at the base, connivent. Stigma bifid with equal branches. Núcules c. 3 mm, dark brown.

Distribution and habitat.-Meso-xerophile grasslands of the subalpine stage, 1700-1900 m. From Russia and Mongolia to central Europe extending locally northwards to Norway and southwards to mountain ranges of Europe (Alps, Dinaric Alps, Carpathians and Pyrenees). In Spain the new population of D. ruyschiana is located in the Central Pyrenees of Catalonia, Artiga de Lin valley, between the Tuc de Pomèro peak and the Barranc dera Ribèra (Val d’Aran county, Lleida province), 31T CH1127 (ETRS89), 1700-1900 m (Fig. 2), on a hillside oriented to the south-east (Fig. 3a). This new population is located more than 10 km far from its nearest population in the French commune of Casaus de Larbost.

The new population of Dracocephalum ruyschiana occurs in a very restricted area, about less than 20.000 m², in a transition zone between acidic sandstones and lutites, and calcareous marbles. At the lower-flat zones at the bottom of the valley, there are mesophile silicicolous grasslands of the montane and subalpine belts of the Pyrenees (habitat CORINE 35.122⁺; see Carreras & al. 2016), and in the steep slopes of the south-east hillside there are mesophile deep soil Festuca spadicea L. grasslands (CORINE 36.3312) and subalpine calcicolous semi-dry grasslands with Festuca spadicea L. and Rhaponticum centauroides (L.) O.Bolòs of the sunny slopes of the Pyrenees (CORINE 34.32613⁺) clumpered with rock outcrops. Dracocephalum ruyschiana is restricted to the borders of rock outcrops, in a thin zone with deep soils but where the subalpine mesophile grasslands are not dense (Fig. 3b, c). The species grows together with Anthericum liliago L., Asphodelus albus Mill., Aster alpinus L., Carduus defloratus subsp. argemone (Pourr. ex Lam.) O. Bolòs & Vigo, Centaurea nigra L., Clinopodium alpinum (L.) Kuntze, Crepis pyrenaica (L.) Greuter, Cruciata glabra Ehrend., Dianthus hyssopifolius L., Festuca spadicea L., Galium verum L., Geranium sanguineum L., Globularia nudicaulis L., Hippocrepis comosa L., Hypericum richeri Vill., Iris latifolia (Mill.) Voss, Laserpitium latifolium L., Laserpitium siler L., Phyteuma orbiculare subsp. anglicum (Rich. Schulz) P. Fourn., Potentilla neumaniana Rchb., Potentilla rupestris L., Rhaponticum centauroides (L.) O.Bolòs, Rosa pendulina L., Scabiosa columbaria L., Sedum rupestre L., Stachys alopecuros (L.) Benth., Stachys officinalis (L.) Trevis., Stachys recta L. and Thymus ovatus Mill.

Phenology.-According to field observations, the species blooms between June and July.

Conservation status.-To evaluate the vulnerability of Dracocephalum ruyschiana, the IUCN (2012a) methodology was applied. Considering the Spanish Pyrenees, the species is restricted to one location included in one 1×1 km, with a population of less than 250 mature individuals (although a precise prospection should be done in the future). With this data, D. ruyschiana should be assessed as “Endangered” EN D (IUCN 2012a). However, applying a regional and national correction (IUCN 2012b) to the IUCN criteria, the category is downlisted to VU° D1+2 because the recolonisation from the neighbouring French populations is possible.

There are currently no major impacts for the newly discovered population and no signs of damaged individuals, population decline or fluctuations, neither indication of reduction in geographic range were detected. But as Leblond & Gourvil (2012), vegetation closure or encroachment, harvesting and isolation are the main threats for the French Pyrenees plant populations. The new population occurs in a narrow zone between rocky habitats and a dense subalpine mesophile grassland, and nor individuals have been seen inside the dense grassland neither in rocky soils. The species occurs near the Artiga de Lin refuge, and some hiking trails pass by near the population, so harvesting by hikers or botanical collectors is a potential threat due to the attractiveness of the flowers. Finally, problems due to isolation could be important because the new population has less than 250 individuals, is restricted to an area of less than 20.000 m² and the nearest population is located further away than 10 km.