Cirsium grahamii, Graham's Thistle
Scientific Name: Cirsium grahamii
Common Name: Graham's Thistle
Family: Asteraceae, Sunflower Family
Synonyms: ( )
Duration: Biennial or perennial
Size: To 3 feet.
Growth Form: Forb/herb; slender taproots; erect; single stem; all parts spiny; thinly arachnoid and puberulent to short-pilose, sometimes glabrate.
Leaves: Green; alternate; oblanceolate to oblong-elliptic; spiny over much of leaf; margins entire, coarsely dentate or pinnatifid, lobes with or without teeth; basal leaves sessile or with narrow wings, basal leaves remain green and healthy at bloom.
Flower Color: Deep purple; large showy discoid flower heads; single or clusters, 3 to 5; phyllaries lanceolate to linear, tipped with many long stiff spines; cypsela tan with dark speckles to dark purplish brown; fruit an achene.
Flowering Season: July or August to September or October, blooms following summer monsoon rainfall.
Elevation: 4,500 to 8,500 feet.
Habitat Preferences: Various high elevation habitats including pine forest openings, evergreen oak communities, closed grassy basins, meadows and other damp soil.
Recorded Range: A rare thistle in the United States with a very limited distribution in northern and southern Arizona and central New Mexico. Graham’s Thistle is also recorded in northern Mexico.
North America & US County Distribution Map for Cirsium grahamii.
U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: In North America the genus Cirsium is listed as a Noxious Weed by the States of Arkansas and Iowa. Plants included here are invasive or noxious.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available
In the Southwestern United States: Arizona has 19 species of Cirsium, California has 26 species, Nevada has 16 species, New Mexico has 19 species, Texas has 12 species, Utah has 23 species. All data is approximate and subject to taxonomic changes.
Comments: There is little botanical information for Graham’s Thistle, which, like many native thistles have limited geographic distribution and are not aggressive or noxious weed as notorious thistles. It appears to be more specialized in its habitat requirements as suggested by its extremely limited geographic range. Like most thistles, Graham’s Thistle attracts many different insects including bees, wasps and butterflies. Superficially similar in appearance to Wheeler’s Thistle, Cirsium wheeleri.
The genus Cirsium has achieved adverse notoriety from two introduced European thistles now wide-spread throughout North America; Canadian thistle, Cirsium arvense is listed as noxious in 33 states and Bull Thistle, Cirsium vulgare, is also a noxious weed. However most southwestern native thistles, including Arizona Thistle, are non-aggressive; non-invasive species that have evolved to thrive without becoming weedy in their respective select geographic southwestern ecosystems. Many native thistles are now threatened with some species at risk of extinction.
As with most thistles, Graham’s Thistle attracts many different insects including bees, wasps and butterflies. The Xerces Society for Invertebrate Conservation acknowledges in their 2017 publication "Native Thistles: A Conservation Practitioner's Guide" that "native thistles are misunderstood and wrongly maligned group of wildflowers..." when in fact native thistles provide resources for many species of bees, butterflies and other wildlife which rely heavily on these species plants. "Monarch butterflies visit native thistle flowers more than any other wildflowers in some regions during their migration back to Mexico".
The genus Cirsium is from the Greek word "kirsion" "a kind of a thistle" which is translated from the Greek word "kirsos" meaning "swollen vein or welt"; a reference to their remedy against swollen veins and welts as thistles were quite often used as a remedy for these types of ailments.
The species epithet grahamii is named in honor of Virginia born James Duncan Graham (1799-1865), a West Point graduate and army officer. Mr. Graham is one of the founders of the army's topographical section and well known for his map making skills.