Cerastium candidissimum Correns is an endangered species. Nevertheless, its ornamental characteristics make it an ideal candidate for commercial use as a new ornamental and landscape plant. As there are no references to the in vitro propagation of this species, the present research aims to comparatively investigate the potential that in vitro propagation may have of three different populations of the plant, from Mounts Parnassos (PS), Parnitha (PR), and Hymettus (HM), respectively. The establishment of the initial cultures took place by cotyledonary- and stem-node explants, excised from in vitro grown seedlings, on Murashige and Skoog (MS) media, without hormone (Hf), or with 0.5 mg L⁻¹ 6-benzyladenine (BA). The shooting percentage was higher in the case of the PS population (97.6%). It was also higher for stem-node explants (93.9%). The multiplication phase took place on Hf MS, or on MS containing BA (0.5 and 1.0 mg L⁻¹), with or without 0.1 mg L⁻¹ 1-Naphthaleneacetic acid. The higher shoot production was observed in the PS and PR populations (88.0% and 76.9% shooting, with 3.1 and 2.7 shoots/explant, respectively). Micro-shoots rooted at high percentages on half-strength MS (80.0–100.0%). Successful acclimatisation (95.0%) was established on peat: perlite (1:1 v/v). Moreover, an efficient alginate-encapsulation procedure was developed from PS stem-node explants, using a 3.0% w/v sodium alginate and 14.7 g L⁻¹ calcium chloride solution. Alginate beads exhibited a higher shoot proliferation (3.8 shoots) after 60 days of storage at 4.0 °C and a 50-day growth on Hf MS than non-encapsulated in vitro node-explants did. The presented protocol of in vitro propagation of C. candidissimum could facilitate the exploitation of the species by the floricultural industry and contribute to conservation strategies.

This study investigated the germination characteristics and genetic variability of Cerastium candidissimum, a Greek endemic species with potential for ornamental horticulture. The seeds were collected from three populations of Mount Hymettus, M. Parnitha, and M. Parnassos. The cardinal temperatures for germination, the effect of seed storage duration, and population-specific germination responses were examined. Germination trials were conducted in vitro on half-strength Murashige and Skoog medium, with seeds tested after dark and dry room storage periods of 6, 18, and 30 months. Seeds from Mount Parnitha exhibited high germination rates (81–94%) within a temperature range of 10–20 °C after 6 and 18 months of storage. Similarly, seeds from Mount Parnassos demonstrated optimal germination (81.3–94.0%) at 10–20 °C after 6 months of storage, though an 18-month storage period shifted the optimal range to 15–20 °C (67–71%). In contrast, the Mount Hymettus population exhibited the lowest germination percentages, with 6-month-old seeds reaching only 47.3% germination at 20 °C, declining to 34% at 15 °C after 18 months, and near-zero germination after 30 months. The time required for 50% germination (T₅₀) ranged from 4 to 8 days at 20 °C across all populations but increased as incubation temperature decreased (4–18 days at 15 °C; 8–18 days at 10 °C). The molecular analysis revealed that the primers used presented high polymorphism (49.0%), and a total of 136 amplified markers were produced. Individuals from different populations were grouped in three different branches. These findings indicate population-level variability in germination traits, likely reflecting genetic and ecological differences. The high germination rates of Parnitha and Parnassos’ populations support their potential use in floriculture. Conversely, the low germination success of the Hymettus population suggests higher environmental stress or genetic constraints, warranting further investigation into its possible classification as a distinct ecotype.