Grindelia lanceolata Nutt.

Spiny-Toothed Gumweed


CC = 3
CW = 5
MOC = 39

© SRTurner

Family - Asteraceae/Astereae

Habit - Taprooted biennial or perennial forb, flowering only once before dying.

Stems - Erect, to 1.5 m, branching above, glabrous, often reddish.

Grindelia_lanceolata_stem.jpg Stem.

© DETenaglia

Leaves - Alternate, simple, sessile. Blades 2-11 cm long, linear to lanceolate-oblong, angled to rounded or occasionally nearly truncate at the base and slightly clasping to moderately sheathing the stem, tapered to a sharply pointed tip, the margins with sparse to moderate sharp teeth, or less commonly some of the leaves entire, the teeth mostly with a minute, bristlelike extension at the tip, the surfaces appearing not or only slightly resinous, with moderate to dense glandular dots, but these inconspicuous and only slightly differing in color from the surrounding leaf tissue. Margins between teeth setulose.

Grindelia_lanceolata_leaves1.jpg Stem and leaves.

© SRTurner

Grindelia_lanceolata_leaf1.jpg Leaf adaxial.

© SRTurner

Grindelia_lanceolata_leaves2.jpg Leaves abaxial.

© SRTurner

Grindelia_lanceolata_leaf2a.jpg Leaf abaxial surface.

© SRTurner

Grindelia_lanceolata_entire.jpg Unusual leaf with entire margins.

© SRTurner

Grindelia_lanceolata_leaves.jpg Pressed leaves.

© DETenaglia

Inflorescence - Solitary heads or loose clusters at branch tips.

Heads - Radiate, short-stalked, with a few short, leaflike, linear bracts which grade into the involucral bracts. Receptacle nearly flat, 1.5-2.0 cm in diameter. Involucre 10-20 mm long, the bracts in 4-6 subequal series, loosely imbricate, linear-attenuate, glabrous, viscid, loosely ascending to slightly curved outward.

Grindelia_lanceolata_head.jpg Flowering head.

© SRTurner

Grindelia_lanceolata_head2.jpg Flowering head.

© SRTurner

Grindelia_lanceolata_involucre.jpg Involucre.

© SRTurner

Grindelia_lanceolata_gum.jpg Young head with gummy exudate.

© SRTurner

Flowers - Ray florets 14-30, pistillate, the corolla 8-16 mm long, yellow, glabrous. Disc florets perfect or some of the inner and/or outer ones functionally staminate, the corollas 4.0-7.5 mm long, yellow, viscid. Pappus of 2 slender awns, 4-8 mm long, these not barbed, not fused at the base, not persistent at fruiting (usually shed individually as the fruit matures), off-white to straw-colored. Stamens 5, adnate to base of corolla tube. Filaments very short. Anthers to 3 mm long, included, connate around style. Style bifurcate. Stigmas pubescent.

Grindelia_lanceolata_flower.jpg Flowering head.

© DETenaglia

Grindelia_lanceolata_florets.jpg Disks and rays.

© SRTurner

Fruits - Achenes 3-6 mm long, straw-colored to light gray.

Flowering - August - October.

Habitat - Glades, upland prairies, upland forest openings, pastures, fields, railroads, roadsides; often on calcareous substrates.

Origin - Native to the U.S.

Lookalikes - None close.

Other info. - This species of Grindelia is found in scattered counties across Missouri, somewhat less commonly north of the Missouri River. Its distribution beyond Missouri is not extensive, being mainly limited to a few states to the south and west. The plant is easily recognized by its sticky, spiny involucres on yellow flowering heads. The small, spiny teeth on the leaves are also distinctive, though plants are occasionally found in which these are absent.

The gummy exudate which gives the plant its name consists of a mixture of terpenes. This sticky resin is often visible as a mass atop the developing disk florets (see photo). The resin has been studied as a potential replacement for conifer resin in industrial applications. It has also been used by Native Americans for a variety of purposes, such as treating sores and lesions, binding together wounds, and as an inhalant for relieving bronchitis and asthma. The flowers are showy and the plant is appropriate for cultivation in drier soils.

Missouri plants have been called var. lanceolata. Other varieties are found in small populations to our west and south. The genus name honors the Latvian botanist David Hieronymus Grindel.

Photographs taken at the Pea Ridge National Military Park, Rodgers, AR., 8-11-03 (DETenaglia); also at Shaw Nature Reserve, Franklin County, MO, 8-11-2006, 8-29-2008, and 10-11-2010, St. Joe State Park, St. Francois County, MO, 9-12-2012, Victoria Glade, Jefferson County, MO, 8-28-2016, Little Lost Creek Conservation Area, Warren County, MO, 8-23-2017, and Glade Top Trail National Scenic Byway, Ozark County, MO, 8-15-2023 (SRTurner).