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Click to read about the Erigeron genus.

Erigeron grandiflorus
Erigeron grandiflorus
Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Colorado Trail above Hillside Drive, June 17 and June 28, 2021.

In the top photograph, two flower heads emerge at ground level and eleven days later another Erigeron grandiflorus flower head just a few feet away begins unfolding at the top of a stem just 1 inch tall.

Erigeron grandiflorus
Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Sharkstooth Trail, June 23, 2008.

Weber indicates that this dainty plant is "uncommon or rare on tundra" in Colorado, but it is considered fairly common on Colorado tundra by John Kartesz in his Synthesis, and the Flora of North America considers it fairly common in much of the Rockies. Ackerfield indicates that it is "common in alpine and subalpine meadows, 9,500-14,000 feet".

The disagreement over abundance is probably due to splitting and lumping.  Weber considers this species distinct from what he considers the much more common Erigeron simplex.  Ackerfield agrees with the Synthesis and the FNA and combines the two species into one, E. grandiflorus.  Interestingly (or maddeningly) Intermountain Flora and Utah Flora also combine the two species but into E. simplex!

Split or lumped, the plant is still lovely, grows primarily (if not exclusively) on tundra, is sometimes minute, and is certainly a treat to find.

Note also that almost all sources indicate that E. grandiflorus grows only in the alpine, but Ackerfield indicates that in Colorado it can be in the subalpine and even as low as 9,500 feet. The FNA indicates "alpine or near timberline" for the range through all of North America.

From collections made by Thomas Drummond in 1826 on the "Summits of the Rocky Mountains" in Canada, William Jackson Hooker named and described Erigeron grandiflorus in volume 2 of his 1834 Flora Boreali-Americana. (Click the title to read Hooker's description and click again to see the beautiful drawings of Erigeron grandiflorus in Hooker's Flora).

Erigeron grandiflorus
Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Calico Trail, Papoose Peak, July 17, 2008.

These E. grandiflorus are nearly four inches tall, have purple hairs on their phyllaries,  and have nearly glabrous (smooth, non-hairy) leaves.  The plant in the photograph immediately above is only an inch and a half tall, has white hairs on its phyllaries, and has minutely hairy leaves. The second photograph at the top of the page shows a plant about 1 1/2 inches tall.

Ray flowers may be white or various intensities of pink to lavender.

These variations are common for this species and are responsible for the variations in descriptions of this plant in various floras. (See the discussion below).

Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Sharkstooth Trail, June 23, 2008.

Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Sharkstooth Trail, June 23, 2008 and Calico Trail, Papoose Peak, July 17, 2008.

The hairs can range from shaggy white to shaggy purple.

Notice that the phyllaries are equal in length, as Welsh's A Utah Flora indicates they should be. The FNA and the Flora of the Four Corners Region indicate that the phyllaries are in 2-3 series. I think what should be said is that the phyllaries may be equal in length or in 2-3 series. A revised examination of E. grandiflorus by O'Kane, Heil, and Nesom indicates "phyllaries in 2–3 subequal [nearly equal] series".

The primary morphological distinction brought out by the revision is shown in the top two photographs on this page. "In alpine tundra and fell fields in southwestern Colorado (San Juan Co.), individuals of Erigeron grandiflorus of extremely reduced size are common and abundant but previously undocumented in that size range –– with stems 2–20 mm tall and involucres 5–7 mm wide producing 17–50 ray florets". 

Various floras agree that the hairs have clear to purple crosswalls (not visible even with a 10x hand lens in the field), but they fail to indicate that the hairs themselves vary from white to dark.

These same problems with the description of the phyllaries and hairs occurs in various floras in their details about Erigeron melanocephalus.

Erigeron grandiflorus
Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Sharkstooth Trail, June 23, 2008.

Erigeron graondiflorus
Erigeron grandiflorus.  Synonym: Erigeron simplex. (Rocky Mountain Alpine Daisy, Large-flowered Daisy)
Asteraceae (Sunflower Family)

Subalpine, alpine. Tundra. Summer.
Colorado Trail at Stony Pass, August 26, 2019.

This Erigeron grandiflorus is far less hairy than most E. grandiflorus plants. Within a few feet of this plant, there were several more hairy plants.

The long, narrow leaves yellowing near their tips belong to another species growing with the shorter, slightly folded, oblanceolate leaves of E. grandiflorus.

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 Erigeron grandiflorus