2.1 Plant material
In the summer of 2020, A. cantabrica populations were sampled
from six locations that collectively represent its distribution range,
as illustrated in Fig. 2A. Within these populations, its distribution is
often fragmented, resulting in multiple subpopulations, notably in Tres
Meras (TM). A total of thirty-five individuals were collected, with six
individuals sampled from each population, except for Hoya Continua (HC),
where only one individual was available for analysis. Three additional
individuals were sampled from different subpopulations within TM, along
with one more from a separate Valdecebollas (VB) subpopulation. Related
taxa of A. cantabrica from the northern Iberian Peninsula were
also sampled, including six individuals from an A. halleri subsp. nuria Schönsw. & Schneew. population (Fig. 2B; Suppl.
Table 1). Fresh leaf tissue samples were dried in silica gel, and
specimen vouchers were preserved at the JACA Herbarium (Suppl. Table 1).
Specimens from the four Alps taxa were obtained from the Kew Herbarium
(Suppl. Fig. 1), with additional sequencing data sourced for related
taxa and Primula matthioli (L.) V.A.Richt. which was selected as
an outgroup (Suppl. Table 2). Field sampling also involved recording
population sizes, key reproductive traits, and the conservation status
of each population. We further reassessed the IUCN category following
the standards set by the IUCN Species Survival Commission (2012).