 Blooming yellow thistle (Bull thistle, Cirsium horridulum) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Yellow thistle (Bull thistle, Cirsium horridulum)(?) in Bastrop State Park. Bastrop, Texas, March 17, 2018
 Yellow thistle (Bull thistle, Cirsium horridulum)(?) on mulch in a tree utilization site in Bastrop State Park. Bastrop, Texas, March 17, 2018
 Yellow thistle (Bull thistle, Cirsium horridulum) on a recently built pipeline in Lick Creek Park. College Station, Texas, April 12, 2021
 Metallic beetles in yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline right-of-way in Lick Creek Park. College Station, Texas, April 12, 2021
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 5, 2019
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 5, 2018
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 6, 2022
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 18, 2022
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 12, 2024
 Yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Flower bud of yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 14, 2019
 Flower of yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 5, 2019
 Blooming yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 5, 2019
 Flower bud of yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 11, 2018
 Flower of yellow thistle (Bull thistle, Cirsium horridulum) with a bronze beetle in Lick Creek Park. College Station, Texas, April 5, 2019
 Winter rosette of yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 11, 2021
 Winter rosette of yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, February 25, 2021
 Basal leaves of yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, February 25, 2021
 Large thorny rosette of yellow thistle (Bull thistle, Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, February 25, 2021
 Yellow thistle (Bull thistle, Cirsium horridulum) on Richards Loop Trail in Sam Houston National Forest. Texas, April 13, 2024
 Yellow thistle (Bull thistle, Cirsium horridulum) on Lone Star Trail in Sam Houston National Forest, near Huntsville. Texas, April 8, 2018
 Yellow spiny thistle (Bull thistle, Cirsium horridulum) at sunrise in Lake Bryan Park. Bryan, Texas, April 13, 2010
 Thistle (Cirsium) in Bastrop State Park. Bastrop, Texas, September 15, 2012
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, March 31, 2024
 Yellow flower of bull thistle (Cirsium horridulum) in Lick Creek Park. College Station, Texas, April 18, 2022
 Seeds of yellow thistle (Bull thistle, Cirsium horridulum) on sewage line right-of-way in Lick Creek Park. College Station, Texas, May 2, 2023
 Rosette of leaves of yellow thistle (Bull thistle, Cirsium horridulum) in Lick Creek Park. College Station, Texas, January 10, 2024
 Yellow thistle (Bull thistle, Cirsium horridulum) on Post Oak Trail in Lick Creek Park. College Station, Texas, March 26, 2019
 Opening flower of bull thistle (Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Yellow flowers of bull thistle (Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Large flower bud of bull thistle (Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Fluffy seeds of yellow thistle (Bull thistle, Cirsium horridulum) on sewage line right-of-way in Lick Creek Park. College Station, Texas, May 2, 2023
 Flower bud of yellow thistle (Bull thistle, Cirsium horridulum) on Post Oak Trail in Lick Creek Park. College Station, Texas, March 26, 2019
 Arrangement of seeds of yellow thistle (Bull thistle, Cirsium horridulum) on sewage line right-of-way in Lick Creek Park. College Station, Texas, May 2, 2023
 Yellow thistle (Bull thistle, Cirsium horridulum) on Whitman Road, near Washington. Texas, March 22, 2009
 Immature seed head of yellow thistle (Bull thistle, Cirsium horridulum) on sewage line right-of-way in Lick Creek Park. College Station, Texas, May 2, 2023
 Yellow thistle (Bull thistle, Cirsium horridulum) on a forest opening over a sewage line in Lick Creek Park. College Station, Texas, March 31, 2023
 Rosette and yellow flowers of bull thistle (Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Bull thistle (Cirsium horridulum) at Lake Somerville Trailway near Birch Creek Unit of Somerville Lake State Park. Texas, April 5, 2020
 Blooming bull thistle (Cirsium horridulum) on Richards Loop Trail in Sam Houston National Forest. Texas, April 9, 2022
 Top view of Bull thistle (Cirsium horridulum) on Richards Loop Trail in Sam Houston National Forest. Texas, April 9, 2022
 Yellow thistle (Bull thistle, Cirsium horridulum) in Lake Bryan Park. Bryan, Texas, March 20, 2010.
 Side view of a large yellow flower of bull thistle (Cirsium horridulum) on a pipeline clearing in Lick Creek Park. College Station, Texas, March 24, 2021
 Bull thistle (Cirsium horridulum)(?) on a golf course on campus of Texas A and M University. College Station, Texas, February 14, 2021
 Icy rosettes of bull thistle (Cirsium horridulum)(?) on a golf course on campus of Texas A and M University. College Station, Texas, February 14, 2021
 Rosette of bull thistle (Cirsium horridulum)(?) on a golf course on campus of Texas A and M University. College Station, Texas, February 14, 2021
 Fluffy seeds of bull thistle (Cirsium horridulum) in Lick Creek Park. College Station, Texas, May 7, 2018
 Winter rosette of bull thistle (Cirsium horridulum) with freeze in Lick Creek Park. College Station, Texas, January 3, 2022
 Leaves of bull thistle (Cirsium horridulum) in area of a former pond in Washington-on-the-Brazos State Historic Site. Washington, Texas, February 20, 2022
 Bull thistle (Cirsium horridulum) on a forest clearing on Caney Creek Trail (Little Lake Creek Loop Trail) in Sam Houston National Forest north from Montgomery. Texas, April 11, 2021
 Rosette of leaves of bull thistle (Cirsium horridulum) in area of a former pond in Washington-on-the-Brazos State Historic Site. Washington, Texas, February 20, 2022
 Leaves of bull thistle (Cirsium horridulum) in ultraviolet light on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Rosette of basal leaves of bull thistle (Cirsium horridulum) in ultraviolet light on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Basal leaves of bull thistle (Cirsium horridulum) when exposed to regular daylight as well as when illuminated by a 365 nm ultraviolet (UV-A) blacklight on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Winter rosette of bull thistle (Cirsium horridulum) when exposed to regular daylight as well as when illuminated by a 365 nm ultraviolet (UV-A) blacklight on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Thorny leaves of bull thistle (Cirsium horridulum) when exposed to regular daylight as well as when illuminated by a 365 nm ultraviolet (UV-A) blacklight on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Smaller rosette of basal leaves of bull thistle (Cirsium horridulum) when exposed to regular daylight as well as when illuminated by a 365 nm ultraviolet (UV-A) blacklight on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Central area of rosette of basal leaves of bull thistle (Cirsium horridulum) when exposed to regular daylight as well as when illuminated by a 365 nm ultraviolet (UV-A) blacklight on a sewage line right of way in Lick Creek Park. College Station, Texas, November 15, 2024
 Winter rosette of a thistle in Bastrop State Park. Bastrop, Texas, January 5, 2013
 Thorny winter rosette of a thistle in Bastrop State Park. Bastrop, Texas, January 5, 2013
 Winter rosette of musk thistle (Carduus nutans, Asteraceae) in Bastrop State Park. Bastrop, Texas, February 23, 2020
 Painted lady butterfly (Vanessa virginiensis) on a thistle on Lost Pines Trail in Bastrop State Park. Bastrop, Texas, May 2, 2010
 Blooming garlic in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Bolbitius mushrooms in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Garlic flowers in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Ground cherries (Physalis) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Burned trail marker in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Blooming spiderwort (Tradescantia) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Rainbow scarab (Phanaeus vindex) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Queen s delight (Stillingia sylvatica) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Ascomycete fungus Pyronema omphalodes in ash pit in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Giant Swallowtails (Papilio cresphontes) nectaring on a thistle flower on Lost Pines Trail in Bastrop State Park. Bastrop, Texas, May 2, 2010
 Flower-feeding scarab (Euphoria kerni(?), adult) in a thistle on Lost Pines Trail in Bastrop State Park. Bastrop, Texas, May 2, 2010
 Rosette and a seedling of milk thistle (Silybum marianum, Carduus marianus) at Lake Spur Trail in Bastrop State Park. Bastrop, Texas, December 25, 2011
 Rosette of leaves of milk thistle (Silybum marianum, Carduus marianus) on a site of a recent burn in Bastrop State Park. Bastrop, Texas, February 23, 2020
 Yellow flower of rock-rose (frostweed, sunrose, Helianthemum carolinianum) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Texas greeneyes (Berlandiera betonicifolia) in Bastrop State Park. Bastrop, Texas, April 25, 2021
 Mature Laetiporus(?) mushroom on oak wood in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Horseweed and yellow asters in a burned forest in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Caps of mushrooms Gloeophyllum striatum on oak wood in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Tinder mushrooms Gloeophyllum striatum on oak wood in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Small Agrocybe mushrooms in a sparse forest in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Blackening waxcap mushrooms (Hygrocybe conica) in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Peeling puffball mushrooms (Lycoperdon marginatum) in Bastrop State Park. Bastrop, Texas, October 17, 2021
 Various lichens on sandstone of Lost Pines Overlook in Bastrop State Park. Bastrop, Texas, February 28, 2021
 Red berries and leaves of Yaupon holly cut by ants in Bastrop State Park. Bastrop, Texas, December 25, 2021
 Mosses in wet area in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Burnt hill in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Fruits of blackberry in Bastrop State Park. Bastrop, Texas, April 15, 2023
 Toad pond in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Fehr s Overlook in Bastrop State Park. Bastrop, Texas, April 21, 2012
 A pond in a forest in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Sunrise in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Ash pits in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Roosevelt s Cutoff Trail in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Fehr s Overlook Shelter in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Hill treated by mulch in Bastrop State Park. Bastrop, Texas, April 21, 2012
 Area around Fehr s Overlook in Bastrop State Park. Bastrop, Texas, April 21, 2012
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