Astragalus lentiginosus Douglas ex Hook.
A. l. var. borreganus flowers.
...the most annoying group of forms in the genus (Jones 1895: 672)
...the most variable of all Astragali (Jones 1923: 123)
...ill-defined and perhaps chimerical (Barneby, 1945 p. 65)
...is hardley a species in any conventional sense of the term. (Barneby 1964: 912)
...an excessively polymorphic complex which embraces a range of variation far greater than can appear reasonable (Barneby 1964: 912)
...as unwieldy in the mass as it is intricate in internal structure (Barneby 1964: 912)
...unwieldy and vastly multiracial (Isely 1998: 319)
What is Astragalus lentiginosus?
Astragalus lentiginosus is a single species that contains so much morphological diversity that it is divided into 36 varieties. Many of these varieties were originally described as discrete species. As collections from western North America increased during the late 19th century it became apparent that intermediate forms connected these species such that they should be considered one species containing many varieties.
How did we get so many varieties?
Although varieties have been included in Astragalus lentiginosus almost since its inception, the idea of a single species consisting of numerous varieties should be credited to Marcus E. Jones (1895, 1923). Per Axel Rydberg employed a very different taxonomic concept in his contribution to the Flora of North America (1929), raising Jones's varieties to species within the genera Cystium Steven and Tium Medic. Barneby (1945, 1964) became a moderator between these two very different opinions, while adding his own opinions as well. It is Barneby's system of one species with many varieties, following Jones, that appears in most modern floras.
How many varieties are there?
The number of varieties have varied through time and with the opinions of the monographers. The species was described in 1831 by David Douglas and William Jackson Hooker. Marcus E. Jones originated the concept of one species with many varieties and included 18 varieties in his 1923 revision of North-American Species of Astragalus. Barneby included 40 varieties in a 1945 monograph of the species but reduced this number to 36 in his 1964 Atlas of North American Astragalus. Isely included 40 in his 1998 Native and Naturalized Leguminosae (Fabaceae) of the United States. Through time some varieties have been lumped into synonymy under other varieties. But discovery is not over! New varieties have been described in 1977 (Barneby 1977), 1981 (Welsh & Barneby 1981; Welsh 1981) and 2001 (Welsh & Atwood 2001).
How can you make sense of it? Here's a set of tables I've created in order to help me understand the
major treatments of Astragalus lentiginosus (pdf).
Recognized taxa (alphabetical):
This list represents an amalgamation of Barneby’s most recent treatments (1964 & 1989) as well as the taxa described since these works.
(MSWord ".doc" format)
Brian Knaus's Homepage Astragalus lentiginosus Brian's Links
Last modified 1-10-2006
Questions or comments contact: knausb@science.oregonstate.edu