Blue flower of spring violet (viola) in Lisiy Nos, west from Saint Petersburg. Russia, June 1, 2017
Veined flower of blue violet on Little Lake Creek Loop Trail in Sam Houston National Forest. Richardson, Texas, February 22, 2009
Flower of blue violet. Dibuny, north-west from Saint Petersburg, Russia, June 1, 2014
Blue violet (Viola) flower in Upper Park in Lomonosov (Oranienbaum). West from Saint Petersburg, Russia, May 23, 2017
Flower of blue violet (Viola) in a pine forest at Little Lake Creek Loop Trail in Sam Houston National Forest. Richards, Texas, March 8, 2019
Common blue violet (Viola) flower in a forest in Pavlovsk Park. Pavlovsk, a suburb of Saint Petersburg, Russia, May 16, 2019
Flower of common blue violet (Viola sororia) on Richards Loop Trail in Sam Houston National Forest. Texas, March 3, 2024
This composite image documents four stems of Hedeoma hispida (Rough False Pennyroyal) demonstrating the plant s appearance under two different lighting conditions against a dark background. The top panel shows the specimens under standard white light. The stems feature opposite, linear leaves and are covered in fine, bristly hairs, giving the plant its "rough" descriptor. Clusters of tiny, tubular, purplish-blue flowers emerge from the leaf axils along the upper portions of the stems, nestled within spiky, bristly calyces. The overall coloration is a vibrant, natural green with delicate violet floral accents. The bottom panel reveals the same four specimens illuminated by a 365 nm ultraviolet (UV-A) blacklight. Under UV excitation, the plant exhibits striking fluorescence. The previously purplish-blue flowers fluoresce a brilliant, vivid pinkish-red, while the green stems, leaves, and bristly hairs emit a cool, icy blue-white glow. This stark contrast highlights the complex photochemical properties of the plant tissues, transforming the subtle daytime appearance into a dramatic, high-contrast display. College Station, Texas, April 30, 2026 Blooming Rough False Pennyroyal (Hedeoma hispida) both in natural light and under 365 nm ultraviolet (UV-A) blacklight collected on a lawn at crossing of Holleman Drive and Dartmouth Street. College Station, Texas, April 30, 2026