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Gumweed (4)

The Grindelia genus, Gumweeds, ooze a whitish, viscous, resinous fluid from their flower buds so are very recognizable. There are conflicting descriptions of the species, but I think these are unique enough to be identified individually.

Grindelia nuda

Curlytop Gumweed
Grindelia nuda var. aphanactis
(G. squarrosa var. nuda)

Family: Sunflower (Asteraceae)
AKA: Rayless Gumweed, Resinweed
Photo taken on: October 13, 2010
Location: White Rock, NM
Life Zones: Plains to foothills
Habitat: Dry open areas, pinyon-juniper woodlands

Grows to 16" with a wiry, reddish stem.  Leaves are oblong and  toothed with no stalks. Bracts are sticky and curl backwards. Flower heads have only disk flowers.

Recognized by the USDA Plants Database but considered a variety of G. squarrosa by Flora of North America

Grindelia inornata

Colorado Gumweed
Grindelia inornata
(Grindelia hirsutula var. inornata)

Family: Sunflower (Asteraceae)
AKA: Resinweed, Rayless Gumweed
Photo taken on: September 17, 2011
Location: Wet Mountains, Eastern CO
Life Zones: Plains to foothills
Habitat: Dry open slopes, fields

Grows to 30" with stout stems and fleshy leaves. Flower heads do not have ray flowers, are 1" across and very sticky. Bracts are bright green and curved backwards. Grows south from Denver on the eastern slope.

Identified from G. K. Guennel's Wildflowers of Colorado.

Flora of North America recognizes it as a variety of Grindelia hirsutula, the USDA Plants Database lists it as a distinct species.

Grindelia squarrosa

Curlycup Gumweed
Grindelia squarrosa

Family: Sunflower (Asteraceae)
AKA: Resinweed
Photo taken on: August 26, 2014
Location: SR 114, Saguache, CO
Life Zones: Plains to foothills
Habitat: Roadsides, waste places

Grows to 2 feet with a green or whitish stem. Leaves are oblong and toothed with no stalks. Bracts are in 5 to 6 rows and are strongly hooked. Ray flowers may or may not be present.

 Grindelia squarrosa

Flora of North America reference.

Grindelia fastigiata

Pointed Gumweed
Grindelia fastigiata
(Grindelia hirsutula var. fastigiata)

Family: Sunflower (Asteraceae)
AKA: Erect Gumweed
Photo taken on: October 5, 2021
Location: Fisher Towers Trail, Moab, UT
Life Zones: Plains to foothills
Habitat: Sandy areas, washes

Grows over 3 feet tall with a whitish brownish stem. Leaves have no stalks and lance-shaped and may or may not be toothed. Bracts are thick and are strongly hooked. Flower head has no ray flowers.

Flora of North America recognizes it as a variety of Grindelia hirsutula, the USDA Plants Database lists it as a distinct species.

Yellow Round Clusters