Seed collection and storage
Castilleja sulphurea mature fruits (capsules) were collected from 20 haphazardly chosen plants at 2900-3100 m near the Rocky Mountain Biological Lab (RMBL) in Gothic, Colorado, USA in September 2016. Bouteloua gracilis seeds collected in 2017 from Montezuma County, Colorado, USA at 1828 m were obtained from a local seed supplier (Western Native Seed, Coaldale, Colorado, USA). All seeds were stored in a 4°C refrigerator until processing.
Quantities: 20 plants for C. sulphurea seed collection, seeds from 1828 m elevation site for B. gracilisDuration: Seeds collected in September 2016 for C. sulphurea, 2017 for B. gracilisConditions: Collection sites at 2900-3100 m and 1828 m elevation respectively, storage at 4°C
Equipment: 4°C refrigerator
Seed stratification and germination setup
C. sulphurea seeds were cold-stratified in spring 2018 by placing on moist filter paper in sealed Petri dishes in a 4°C refrigerator for ~120 days. Seeds were then sown in trays containing standard soil mixture (57% sand, 43% peat moss, and various minerals) and grown in a growth chamber at 21°C, 50% relative humidity and 4.4°C, 20% relative humidity on a 12:12 h light:dark cycle. Seeds were monitored daily for germination.
Quantities: 120 day stratification period, 21°C day temperature, 4.4°C night temperature, 50% and 20% relative humidity, 12:12 hour photoperiodDuration: ~120 days for stratification, daily monitoring during germinationConditions: 4°C refrigerator for stratification, controlled growth chamber conditions
moist filter paper, sealed Petri dishes, 4°C refrigerator, growth chamber (Conviron MTR30)