Set up wind tunnel apparatus
Wind tunnel consisted of handheld gas leaf blower (B250 27-cc 2-cycle 205 mph 450 cfm; Craftsman, Towson, MD, USA), intake bell, aluminum honeycomb flow straightener (3.18-mm cell), testing chamber, and rear mesh seed trap. Calibrated wind tunnel to have air speeds at or near 5 m/s (11.2 mph) at end of launch platform. Placed wooden launch platform centered and adjacent to flow straightener, with launch platform level and focal plant 15 cm away and centered relative to launch platform.
Quantities: Wind speed maintained at 5 m/s, platform 15 cm from focal plantDuration: Calibration and setup before each trialConditions: Dry conditions to maintain consistency, trials done only under dry conditions
Equipment: Craftsman B250 gas leaf blower, aluminum honeycomb flow straightener (3.18-mm cell), testing chamber, mesh seed trap
Conduct seed launching trials
Individually launched seeds by placing each seed with forceps at edge of launch platform, with seed's longest axis pointed at plant and pappus (when applicable) pointed toward ambient wind. After successful launches, left blower on for 30 s. Considered launches successful if seed contacted plant without first touching ground. Seeds trapped if they were physically touching focal plant or directly beneath canopy for entirety of trial. Measured trapping on five plants per focal species from range of sizes by measuring length of longest axis of each plant.
Quantities: Five plants per focal species (Heterotheca villosa and Lupinus argenteus), multiple seeds per plant. H. villosa length 7-54 cm (mean 27.2 cm), L. argenteus length 4-45 cm (mean 20.2 cm)Duration: Left blower on for 30 seconds after each successful launch. Experiment conducted 1-8 August 2021