Foothills. Openings. Summer, fall.
Prater Ridge Trail, Mesa Verde National Park, August 13, 2005.

Grindelia arizonica (and G. squarrosa pictured below) typically grows several feet high and wide in a bushy shape with numerous bright yellow flowers which often have fairly erect ray flowers.  Grindelia flowers have a strange and strong medicinal smell.  Stems of G. arizonica are often red and the toothed leaves are well-space along the stem giving the plant its characteristic open appearance.

Both plants pictured on this page are commonly called "Gumweed" because of their very sticky phyllaries.  "Grindelia" honors David Hieronymus Grindel, Russian chemist, pharmacist, and doctor.  (More biographical information.)

Foothills. Openings. Summer, fall.
Prater Ridge Trail, Mesa Verde National Park, August 13, 2005.

The very prominent phyllaries (the green overlapping structures below the yellow ray flowers) are sticky, in four or five rows, and, in this species, are vertical, not curved back at the tips.

Semi-desert. Openings. Summer, fall.
Hunter Canyon, Utah, September 26, 2005.

Grindelia fastigiata most often has no ray flowers but it does hybridize with G. squarrosa so ray flowers may be present.  G. fastigiata grows to four feet tall in sand or clay soils in dry open places and along washes, as in this picture.  It is just as sticky and aromatic as the other Grindelias shown on this page.

"Fastigi" is Latin for "pointed", perhaps referring to the sharply pointed bracts and/or to the pointed appearance of the disk flowers as shown in the photograph below.

The plant, first discovered for science by Edward Greene in 1896 near Grand Junction, Colorado, is endemic to the Colorado Plateau.  (More biographical information.)

Foothills. Openings. Summer, fall.
Dolores River Canyon, August 20, 2005.

From a distance, the two species of Grindelia pictured on this page are very similar looking.  Close-up the most noticeable difference is the curving of the phyllaries on this species.  Stems are usually green, not red, and leaves are more serrated than in G. arizonica.  

"Squarrosa" is Latin for "scaly or rough". 

Meriwether Lewis collected this plant on the banks of the Missouri River, probably in 1806, and Pursh named it Donia squarrosa in 1814.  It was renamed Grindelia squarrosa by Dunal in 1819.

Foothills. Openings. Summer, fall.
Dolores River Canyon, August 20, 2005.

The arching phyllaries of G. squarrosa are prominent and a key to identifying this plant.