ANHC’s botanists routinely discover previously unknown populations of species considered by the ANHC to be rare and occasionally discover species not known from the state at all. They have made several notable discoveries in the Ozark Plateau of northwest Arkansas and throughout the Ouachita Mountains.
American Brooklime (Veronica americana), a plant not previously known from Arkansas, is being added to the ANHC’s rare plant list after Theo collected a flowering specimen at Healing Springs Natural Area (NA) in Benton County and its identity was confirmed by the world authority on the genus, Dr. Dirk Albach, botanist at the University of Oldenburg, Germany. Theo had discovered several populations in sterile (non-flowering) condition in recent years from several spring-fed wetlands in Benton and Washington counties but needed a fertile specimen to be certain of the identification before adding it to the ANHC’s rare species list. These northwest Arkansas occurrences represent an extension of American Brooklime’s known native range into the south-central U.S.
The discovery at Healing Springs NA came while working on a Benton and Washington County Natural Heritage Inventory project (NHI). On this particular trip Witsell, Aquatic Ecologist Dustin Lynch, and partners from the Arkansas Game and Fish Commission, The Nature Conservancy, and the University of Arkansas Department of Geosciences conducted a three-day inventory focusing on large springs and spring-fed wetlands. While conducting the inventory, two sites of American Brooklime were documented, as well as the first Benton County occurrence of Mosquito Fern (Azolla mexicana), an unusual aquatic fern that floats on the water surface, and several sites for Leafy Pondweed (Potamogeton foliosus), a species on the ANHC’s watch list of species of potential concern found only in spring-fed ponds and streams in the state. The inventory team also documented a large fen, a rare type of groundwater-fed wet meadow at Healing Springs NA.
As part of the NHI project, Witsell studied gravel bars and river banks on the Illinois River, Little Osage Creek, and Osage Creek, gathering data to classify and describe these communities. While visiting Osage Creek, he discovered the first known Arkansas occurrence of Peachleaf Willow (Salix amygdaloides), which will be added to the state’s rare species list. Also 
during this survey, Witsell found an interesting population of wild gourds along Little Osage Creek. These native gourds, called Ozark Wild Gourd or Ozark Egg Gourd (Cucurbita pepo subsp. ovifera var. ozarkana), are believed to be the wild ancestor of several types of cultivated squash including acorn, crookneck, and scallop types, and a wide variety of ornamental gourds cultivated today. Different plants in this population had five 
distinctly different fruit shapes, hinting at the rich genetic diversity found within the species. Evidence suggests that the domestication of these gourds began at least 4,500 years ago and it represents one of only four food plants thought to have been domesticated in eastern North America.
Surveys along four streams within the Ouachita Mountains resulted in 10 documented combined total occurrences for Letterman’s ironweed (Vernonia lettermannii), Ouachita bluestar (Amsonia hubrichtii), Ouachita indigo-bush (Amorpha ouachitensis), sand grape (Vitis rupestris), chalk maple (Acer saccharum var. leucoderme), and sticky hedge-hyssop (Gratiola brevifolia). These are all plants of state conservation concern and the first four are globally rare, with the ironweed, bluestar, and indigo-bush global ranges centered on the Ouachita Mountains.
Photos:
Top — American brooklime (Veronica americana). Photo by Theo Witsell.
Middle — Mosquito fern (Azolla mexicana). Photo by Theo Witsell.
Middle thumbnails — Different plants of the Ozark wild gourd (Cucurbita pepo subsp. ovifera var. ozarkana) with different fruit shapes, found along Little Osage Creek. Photo by Theo Witsell.
Bottom — Letterman's ironweed (Vernonia lettermannii) documented in the Ouachita Mountains. Photo by Brent Baker.
Main photo — American brooklime (Veronica americana). Photo by Theo Witsell.
American Brooklime (Veronica americana), a plant not previously known from Arkansas, is being added to the ANHC’s rare plant list after Theo collected a flowering specimen at Healing Springs Natural Area (NA) in Benton County and its identity was confirmed by the world authority on the genus, Dr. Dirk Albach, botanist at the University of Oldenburg, Germany. Theo had discovered several populations in sterile (non-flowering) condition in recent years from several spring-fed wetlands in Benton and Washington counties but needed a fertile specimen to be certain of the identification before adding it to the ANHC’s rare species list. These northwest Arkansas occurrences represent an extension of American Brooklime’s known native range into the south-central U.S. 
The discovery at Healing Springs NA came while working on a Benton and Washington County Natural Heritage Inventory project (NHI). On this particular trip Witsell, Aquatic Ecologist Dustin Lynch, and partners from the Arkansas Game and Fish Commission, The Nature Conservancy, and the University of Arkansas Department of Geosciences conducted a three-day inventory focusing on large springs and spring-fed wetlands. While conducting the inventory, two sites of American Brooklime were documented, as well as the first Benton County occurrence of Mosquito Fern (Azolla mexicana), an unusual aquatic fern that floats on the water surface, and several sites for Leafy Pondweed (Potamogeton foliosus), a species on the ANHC’s watch list of species of potential concern found only in spring-fed ponds and streams in the state. The inventory team also documented a large fen, a rare type of groundwater-fed wet meadow at Healing Springs NA.
As part of the NHI project, Witsell studied gravel bars and river banks on the Illinois River, Little Osage Creek, and Osage Creek, gathering data to classify and describe these communities. While visiting Osage Creek, he discovered the first known Arkansas occurrence of Peachleaf Willow (Salix amygdaloides), which will be added to the state’s rare species list. Also 
during this survey, Witsell found an interesting population of wild gourds along Little Osage Creek. These native gourds, called Ozark Wild Gourd or Ozark Egg Gourd (Cucurbita pepo subsp. ovifera var. ozarkana), are believed to be the wild ancestor of several types of cultivated squash including acorn, crookneck, and scallop types, and a wide variety of ornamental gourds cultivated today. Different plants in this population had five 
distinctly different fruit shapes, hinting at the rich genetic diversity found within the species. Evidence suggests that the domestication of these gourds began at least 4,500 years ago and it represents one of only four food plants thought to have been domesticated in eastern North America. 
Surveys along four streams within the Ouachita Mountains resulted in 10 documented combined total occurrences for Letterman’s ironweed (Vernonia lettermannii), Ouachita bluestar (Amsonia hubrichtii), Ouachita indigo-bush (Amorpha ouachitensis), sand grape (Vitis rupestris), chalk maple (Acer saccharum var. leucoderme), and sticky hedge-hyssop (Gratiola brevifolia). These are all plants of state conservation concern and the first four are globally rare, with the ironweed, bluestar, and indigo-bush global ranges centered on the Ouachita Mountains. Photos:
Top — American brooklime (Veronica americana). Photo by Theo Witsell.
Middle — Mosquito fern (Azolla mexicana). Photo by Theo Witsell.
Middle thumbnails — Different plants of the Ozark wild gourd (Cucurbita pepo subsp. ovifera var. ozarkana) with different fruit shapes, found along Little Osage Creek. Photo by Theo Witsell.
Bottom — Letterman's ironweed (Vernonia lettermannii) documented in the Ouachita Mountains. Photo by Brent Baker.
Main photo — American brooklime (Veronica americana). Photo by Theo Witsell.