Astragalus scaphoides
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Astragalus scaphoides
Astragalus scaphoides (Bitterroot milkvetch), is a flowering plantFlowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
in the family Fabaceae
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
, found only in a small area of southwest Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and adjacent parts Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
. It grows in shallow, south facing slopes, in semi-arid sage scrub.
Astragalus scaphoides is a perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
herbaceous
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
plant, with pinnate leaves. The pale yellow flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s open in May and are visited by several species of bumblebees and solitary bees, including species from the genera Osmia and Anthophora
Anthophora
The bee genus Anthophora is one of the largest in the family Apidae, with over 450 species worldwide in 14 different subgenera. They are most abundant and diverse in the Holarctic and African biogeographic regions. All species are solitary, though many nest in large aggregations...
.
Plants can be found near Lemhi Pass
Lemhi Pass
Lemhi Pass is a high mountain pass in the Beaverhead Mountains, part of the Bitterroot Range in the Rocky Mountains The pass lies on the Montana-Idaho border on the continental divide, at an elevation of 7373 feet above sea level.-History:...
on the Montana-Idaho border, and near Bannack State Park in Montana.
Plants tend to flower in alternate years, similar to mast year
Mast year
A mast year is a year in which vegetation produces a significant abundance of mast . The term originally applied solely to trees, like oak trees, that produce fruit useful for feeding farm animals...
s in grasses and trees.