Photo 3815485, (c) Roberto R. Calderón, some rights reserved (CC BY-NC), uploaded by Roberto R. Calderón

Attribution © Roberto R. Calderón
some rights reserved
Uploaded by aguilita aguilita
Source iNaturalist
Associated observations

Photos / Sounds

What

Eastern Poison Ivy (Toxicodendron radicans ssp. negundo)

Observer

aguilita

Date

May 22, 2016

Description

Eastern Poison Ivy (Toxicodendron radicans radicans)

22 May 2016
Ray Roberts Lake State Park, Isle Du Bois
Pilot Point, Denton County, Texas

Poison Ivy growing rapidly on the ground two-thirds of the way through a North Texas spring looking to climb and make life a little miserable for the unwary who step too close. There are at least two dominant varieties of Poison Ivy in North America, Western Poison Ivy and Eastern Poison Ivy. Poison Ivy leaves always grow in sets of three hence the saying: "Leaves of three, let them be." The shape of Poison Ivy leaves is one that tends to vary. The subject of our observation is Eastern Poison Ivy, whose range is the eastern half of the United States and Canada. Because of its presence in some of the Texas counties bordering with Mexico, Eastern Poison Ivy also occurs in particular areas of Mexico's Northeast. Moreover, Eastern Poison Ivy is reported to grow in the "mountainous areas of Mexico up to around 1,500 m (4,900 ft). Caquistle or caxuistle is the Nahuatl term for the species." As for Western Poison Ivy, it hardly grows in Texas according to the US Department of Agriculture's Plants Database range map. Apparently, the Texas Panhandle is the only area in Texas where Western Poison Ivy occurs and then only in six counties. Western Poison Ivy does not grow in the North Texas metropolitan region. Poison Ivy is an authentic resident of North America and the Western Hemisphere. Ray Roberts Lake State Park, Isle Du Bois, is administered by the Texas Parks and Wildlife Department.

Sources:

"Toxicodendron radicans," Wikipedia, extended description and bibliography, photographs, accessed 5.25.16, https://en.wikipedia.org/wiki/Toxicodendron_radicans

"Toxicodendron radicans (L.) Kuntze subsp. radicans - Eastern Poison Ivy," Plants Database, US Department of Agriculture, Natural Resources Conservation Service, range map, photographs, description, resources, accessed 5.25.16, http://plants.usda.gov/core/profile?symbol=torar#

"Toxicodendron rydbergii (Small ex Rydb.) Greene - Western Poison Ivy," Plants Database, US Department of Agriculture, Natural Resources Conservation Service, range map, photographs, description, resources, accessed 5.25.16, http://plants.usda.gov/core/profile?symbol=TORY

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