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Tetraneuris acaulis var. arizonica.  Synonyms: Hymenoxys acaulis var. arizonica.
Asteraceae (Sunflower Family)

Foothills to sub-alpine. Openings. Summer.
Lone Mesa State Park, June 7, 2008.

Tetraneuris acaulis

Tetraneuris acaulis var. arizonica. Synonyms: Hymenoxys acaulis var. arizonica.
Asteraceae (Sunflower Family)

Foothills to sub-alpine. Openings. Summer. Lone Mesa State Park, June 7, 2008.

Tetraneuris acaulis is short, lovely, and uncommon in the Four Corners area. Stems have no leaves, varying amounts of hair, and often grow in quite noticeable clumps. The plant prefers dry open areas; those shown on this page are growing in Mancos Shale.

Tetraneuris acaulis is very similar to Tetraneuris torreyana, but various botanical keys disagree on how to tell them apart. The two are said to differ in the greater number of phyllaries (7-10) versus (4-8), or the hairiness of the leaves, or the venation in the leaves, or, most agreed upon, whether the margins of the phyllaries are thin and paper-like at their edges (Tetraneuris torreyana) or green-red to the edges (Tetraneuris acaulis). After comparing the widely varying and contradictory descriptions of these two species by eight botanical experts, I can only conclude that T. acaulis and T. torreyana are extremely similar  --  perhaps identical.

Edward Greene named this genus in 1898.  "Tetraneuris" is Greek for "four nerves", referring to the nerves on the ray flowers, and "acaulis" means "without leaves on the stem".

This species was first collected for science by Bradbury in North Dakota and Pursh named it Galardia acaulis in 1814. It has endured dozens of other names. There are at least four varieties of T. acaulis and the names are ascribed to a number of different authors.

Tetraneuris acaulis

Tetraneuris acaulis

Tetraneuris acaulis var. arizonica

Tetraneuris acaulis var. arizonica. Synonyms: Hymenoxys acaulis var. arizonica.
Asteraceae (Sunflower Family)

Asteraceae (Sunflower Family)

Foothills to sub-alpine. Openings. Summer. Lone Mesa State Park, June 7, 2008 and June 4, 2011 and near Lone Mesa May 10, 2014.

Notice what a great difference there is between the width and length of the yellow ray flowers on the just opening bud in the photograph at top left and the ray flowers on the fully mature flower heads. Descriptions of plants almost always give you the characteristics of the mature flower.

The second photo at left shows the very hairy phyllaries on the bud of the stemless flowerhead tucked tightly into the leaves.  This, too, can fool you and make identification difficult.  Again, one needs a mature flower. The flower stem on this plant will elongate to about 4 inches. 

Notice also, especially as shown in the third photograph, that the leaves are glandular-punctate; i.e., they are dotted with glandular pits. There are also sometimes long hairs scattered or thickly covering the leaf surface.

A very pleasant fruity fragrance emanates from the flower head, especially from the glandular inner surface of the phyllaries and from the receptacle.

Tetraneuris acaulis

Tetraneuris acaulis var. arizonica. Synonyms: Hymenoxys acaulis var. arizonica.
Asteraceae (Sunflower Family)

Foothills to sub-alpine. Openings. Summer. Lone Mesa State Park, June 7, 2008.

The notched petals and the over-lapping rows (two or three) of hairy and broadly lanceolate phyllaries are very attractive characteristics.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Tetraneuris acaulis