Astragalus schmolliae (Schmoll's Milkvetch, Chapin Mesa Milkvetch)
Fabaceae (Pea Family)

Semi-desert, foothills. Shrublands, woodlands, openings. Spring, summer.
Above and left: Mesa Verde National Park, Chapin Mesa, May 19, 2016 and Petroglyph Point Trail, July 21, 2016.

Astragalus schmolliae is among the rarest plants in Colorado and was a candidate for listing as a federally protected species. According to the United States Fish and Wildlife Service as of September, 2020,

"After completing an in-depth species status assessment using the best available science, the U.S. Fish and Wildlife Service is proposing to list the Chapin Mesa Milkvetch as threatened under the Endangered Species Act (ESA) and designate critical habitat for the species."

However, NatureServe goes on to indicate:

"On February 2, 2022, the proposed rule to list Astragalus schmolliae as a threatened species and to designate critical habitat [was] withdrawn. "This withdrawal [the United States Fish and Wildlife Service indicated] is based on our conclusion that the conservation plan for Chapin Mesa milkvetch at Mesa Verde National Park, and its associated implementation plan, in addition to new standard operating procedures for fire management at Mesa Verde National Park, reduce the threats to the species such that it no longer meets the Act’s definition of an endangered species or a threatened species"."

Astragalus schmolliae is found only on Chapin Mesa in Mesa Verde National Park and the adjacent Ute Mountain Ute Tribal Park. It is quite common in Mesa Verde NP and is probably as common on the Ute lands but it has not been surveyed there as thoroughly as it has been in Mesa Verde. Click to read "Population Status Survey of Schmoll’s Milkvetch (Astragalus schmolliae C.L. Porter)".

Astragalus schmolliae grows to about two feet tall with an abundance of ochroleucous (white/yellow) flowers in a loose raceme of 10-28 flowers. Pods develop quickly from lower flowers while upper flowers are still opening and the pods grow quickly to a bit more than an inch long. Many Astragalus are dainty and easy to overlook; Astragalus schmolliae is tall, wide, and often in large patches so it is relatively easy to find and identify. It is a fitting tribute to Hazel Schmoll.

The history of Astragalus schmolliae's discovery and description is convoluted:

Astragalus expert Rupert Barneby indicates in his 1964 "Atlas of the North American Astragalus" published in the Memoirs of the New York Botanical Garden,

"Although only described in recent years, A schmolliae was first collected in 1890 by Alice Eastwood. Her specimen (click to see in the Smithsonian herbarium), taken in July, was too far advanced to show the full characters of the species, but Jones [later] recognized it as a relative of A. coltonii and Rydberg [later and incorrectly] identified the detached fruit as that of A. lonchocarpus [another closely related species]".

Take a look at A. coltonii and A. lonchocarpus and you will see how similar they are to each other and to A. schmolliae.

After Eastwood made her collection in 1890, the plant was not collected again for science until Aven Nelson (founder of the Rocky Mountain Herbarium) collected it in Mesa Verde National Park on May 12, 1925. (Pages 35 and following of Nelson's journal from his southwestern collecting trip of 1925 list 27 species that he collected May 12-13 in the canyons and on the mesas of Mesa Verde, but a search through SEINet will show that he actually collected about 35 species in Mesa Verde and another 35 in the Cortez area May 10-13.) Click to see the specimen that Nelson collected and mistakenly identified as Astragalus macrocarpus. Note that Cedric Porter (Assistant and then Curator of the Rocky Mountain Herbarium from 1937 to 1968) indicated on Nelson's collection that it is the "type" specimen for Astragalus schmolliae, but see below.

On May 26, 1925, just two weeks after Nelson made his collection, Hazel Schmoll and 12 year-old Deric Nusbaum, son of Mesa Verde National Park Superintendent Jesse Nusbaum, collected the plant northeast of Spruce Tree House in Mesa Verde. (From May-July of 1925 Hazel and Deric (and sometimes Jesse) collected over 500 specimens in Mesa Verde.) Either Schmoll and the Nusbaums did not realize they had a new species or they planned to describe it but never did, or? Schmoll labeled the specimens, "Astragalus", kept one specimen at Mesa Verde and sent other specimens to Brigham Young University, Colorado State University, the Natural History Museum of Utah, and two were sent to the Rocky Mountain Herbarium (click to see one) and (click again to see the other) where, in 1945, Cedric Porter (Curator of the Rocky Mountain Herbarium) saw them and realized they had never been named and described. Click to read Porter's description of the new species.

Schmoll and Nusbaum must have known that Nelson was in the Park collecting, but I can find no reference to this coincidence of collections. Why Porter chose the Schmoll and Nusbaum collection as the type rather than Nelson's as the type and why he named the species for Schmoll rather than Nusbaum or Nelson is also unknown, but a logical explanation is that Nelson and Porter agreed that Nelson had many accolades and Schmoll deserved this one.

As indicated by Porter on the Schmoll Rocky Mountain Herbarium specimens, they are the "type", one for the fruits and one for the flowers. The specimens at the other herbaria are isotypes. Porter also labeled the Nelson collection as the "type" but in his published description, he designates the Schmoll/Nusbaum Rocky Mountain collection numbers 105888 and 105889 as the "type" and then refers to the Nelson collection as the "cotype", a term no longer accepted.

Apparently around 1960 Barneby examined the Eastwood collection that had found its way to the Smithsonian herbarium and he realized that it was the same taxon that Schmoll had collected and Porter had named and described. Since Eastwood never named and described the specimen she collected in 1890, she is not given credit for being the first to collect the species for science.

The species is named for Hazel Schmoll (1890-1990), the first woman to receive a PhD in botany from the University of Chicago. She served as the State Botanist of Colorado. (Click to read more about Schmoll).

Semi-desert, foothills. Shrublands, woodlands, openings. Spring, summer.
Mesa Verde National Park, Chapin Mesa, May 19, 2016.

Astragalus schmolliae leaves grow from about 1 1/2 to 4 inches long. Leaflets are covered with strigose hairs, i.e., hairs which are short, stiff, straight, pointed, and appressed.

Semi-desert, foothills. Shrublands, woodlands, openings. Spring, summer.
Mesa Verde National Park, Chapin Mesa, May 19, 2016.

The stem base is commonly a light red to brown transitioning to green several inches above ground level.

Range maps © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Questionable presence

Range map for Astragalus schmolliae