Cirsium grahamii, Graham's Thistle

As with most thistles, Graham’s Thistle attracts many different insects including bees, wasps and butterflies. Here a bumblebee of the genus Bomus takes nectar from deep within the floral tubes. Cirsium grahamii

Graham's Thistle blooms from July or August to September or even October. Flowering responds well to heavy summer monsoon rainfall. Cirsium grahamii

Graham's Thistle has thick green, alternate leaves spiny over much of the leaf. The basal leaves remain green and healthy at bloom. Cirsium grahamii

Graham's Thistle is relatively rare in the United States where it is limited in distribution to portions of Arizona and New Mexico. Plants prefer various high elevation habitats including pine forest opening, evergreen oak communities, closed grassy basins, meadows and other damp soil. Cirsium grahamii

Scientific Name: Cirsium grahamii
Common Name: Graham's Thistle
Also Called:

Family: Asteraceae, Sunflower Family

Synonyms: ()

Status: Native

Duration: Biennial or perennial

Size: Up to 3 feet (90 cm).

Growth Form: Forb/herb; generally 1 stem, erect, branches 0 to 4; all parts spiny; slightly cobwebby looking (arachnoid) and covered with small soft hairs (puberulent) or sometimes without any hair (glabrate).

Leaves: Green; alternate along stem and branches; leaf blades oblanceolate to oblong-elliptic; spiny over much of leaf; the edges or margins of the leaf entire, coarsely dentate to deeply pinnatifid, lobes with or without teeth; basal leaves sessile or with narrow wings, basal leaves often remain green and healthy at bloom, basal leaves sometimes clasping.

Flower Color: Deep purple; large showy discoid flower heads slightly cobwebby (arachnoid) or without hairs of any kind (glabrous), flower heads single or clusters of 3 to 5; phyllaries lanceolate to linear, tipped with many long stiff spines; fruit is a cypsela, tan with dark speckles to dark purplish brown.

Flowering Season: July or August to September or October, blooms following summer monsoons.

Elevation: 4,500 to 8,500 feet (1,400-2,600 m)

Habitat Preferences: Various high elevation habitats including pine forest openings, evergreen oak communities, closed grassy basins, meadows and damp soil.

Recorded Range: A rare thistle in the United States with a very limited distribution in the mountains of southeastern Arizona and southwestern New Mexico. Graham’s Thistle is also recorded in northern Mexico (Chihuahua, Durango, Sonora and Nuevo León).

North America & US County Distribution Map for Cirsium grahamii.

North America species range map for Cirsium grahamii:
North American range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation

North America species range map for Cirsium grahamii: Click on image for full size map.

Click image for full size map

U.S. Weed Information: Unknown

Invasive/Noxious Weed Information: In North America the genus Cirsium is listed as a Noxious Weed by the States of:

Arkansas, listed as a “Noxious weed”,

Iowa, listed as a “Primary noxious weed”.

Plants included here are invasive or noxious. See the Comments: section below for additional information regarding “noxious” thistles.

Wetland Indicator: Unknown
Threatened/Endangered Information: Unknown

Genus Information: In North America there are 91 species for Cirsium. Worldwide, The Plant List includes 481 accepted species names and a further 812 scientific names of infraspecific rank for the genus.

The genus Cirsium was published by Philip Miller in 1754.

In the Southwestern United States: Arizona and New Mexico each have 19 species of genus, California has 26 species, Nevada has 16 species, Texas has 12 species, Utah has 23 species. All data approximate and subject to revision.

Comments: There is little botanical information for Graham’s Thistle which like many native thistles have limited geographic distribution and are not aggressive or a noxious weed as notorious thistles. It appears to be more specialized in its habitat requirements as suggested by its extremely limited geographic range.

Superficially similar in appearance to Wheeler’s Thistle, Cirsium wheeleri.

The genus Cirsium in general, has received adverse notoriety because of the introduction of two thistles native to Europe and now widespread throughout North America. The Canadian Thistle, Cirsium arvense and and the Bull Thistle, Cirsium vulgare are both listed as noxious primarily by agricultural interests. The Canadian Thistle and Bull Thistle together for example are listed as noxious weeds in 33 and 9 states respectively.

In reality, most southwestern native thistles, including Graham's Thistle, are non-aggressive; non-invasive and beneficial as pollinators. Our native thistles have evolved over thousands of years and have mostly thrived without ever becoming weedy. However, many native thistles are now threatened and some species are at risk of extinction.

In Southwest Desert Flora also see; Arizona Thistle, Cirsium arizonicum, New Mexico Thistle, Cirsium neomexicanum, Mojave Thistle, Cirsium mohavense and Yellowspine Thistle, Cirsium ochrocentrum.

Importance to Wildlife, Birds and Livestock Thistles of the genus Cirsium are regularly visited by many wildlife species such as small mammals, hummingbirds and nectar-feeding bats. Also the seeds are attractive to finches including the American goldfinch and many other birds.

Special Value to Native Bees, Butterflies and Insects Thistles of the genus Cirsium are important as a group as they are provide nectar and pollen for bees and they are frequently visited by pollinators such as Native bees, bumblebees and an exceptionally large number of insects and butterflies. "Monarch butterflies visit native thistle flowers more than any other wildflowers in some regions during their migration back to Mexico". They are also heavily used as food plants by the larvae of some Lepidoptera (butterfly) species. In addition to food Cirsium also provides nesting material and structure for Native bees and other insects.

To find out more about Butterflies and Moths of North America visit BAMONA.

For an interesting article on native thistles in North America see Native Thistles: A Conservation Practitioner's Guide, published on-line by The Xerces Society, For Invertebrate Conservation.

Etymology: The genus Cirsium is derived from the Greek words kirsion "a kind of thistle" in turn from kirsos, "a swollen vein or welt," as thistles are used as a remedy for such issues.

Thistles of the genus Cirsium are known as “plume thistles” because they have feathered hairs on their pappi while thistles of the genera Carduus, Silybum and, Onopordum have a pappi with simple unbranched hairs.

The genus Cirsium was published by Philip Miller in 1754.

The species epithet grahamii (gra'hamii:) is name in honor of James Duncan Graham (1799-1865), a West Point Graduate and U.S. Army Officer. Mr. Graham is the namesake of Mount Graham, in Graham County, Arizona, and Graham County, Arizona was named after Mount Graham. Mr. Graham is also one of the founders of the United States army's topographical section and well known for his map making skills.

Ethnobotany Unknown