Scientific Note: the Role of Pre-stratification Dry Storage Time in Germination Success of an Imperiled, Southern Appalachian Endemic, Houstonia montana (Rubiaceae)

Houstonia montana Small (Rubiaceae) is a federally-listed herbaceous perennial known only from 16 populations across the rock outcrops and grassy balds of North Carolina, Tennessee, and Virginia. Species recovery objectives include augmentation and/or (re)introduction into suitable habitat and the establishment of a long-term conservation collection. However, before any action involving germplasm storage or plant propagation can be pursued, the seed biology of the species must be more fully understood. This study aimed to assess the effect of pre-stratification dry storage time on germination success. Seeds were collected from two populations of H. montana in October 2023 and subsequently stored at dry, ambient conditions for three durations of time: two weeks, three months, and six months post collection. After dry storage, seeds were cold-stratified in moist filter paper at 3°C for 60 days and then transferred to moist filter paper in petri dishes for germination under controlled conditions in a growth chamber. Germination reached 88–100% across the dry storage treatments and populations, indicating high seed viability for seeds stored up to six months before cold stratification. Time-to-event analysis identified a significantly faster germination rate for seeds stored for two weeks post-harvest compared to seeds stored for three or six months but there were no significant differences in germination rate in the latter two treatments. Collectively, the results provide a basis for the timing and planning of projects requiring seed germination of Houstonia montana and point towards a two-week dry storage time before cold stratification for quick germination with high seedling yield.