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    "Solidago" is from the Latin "solidus" meaning "whole" or "solid", referring to the plant's supposed medicinal use for healing injuries. Linnaeus named this genus in 1753.  "Goldenrod" is a common name applied to all Solidagos.

    The two species of Solidago shown on this page are very similar and no two floras agree on their distinguishing characteristics. Some floras separate them on the basis of the number of ray flowers, indicating that S. multiradiata has about 13 ray flowers and S. simplex about 8. However, other floras, e.g., the Flora of North America indicate that S. multiradiata has 12-18 ray flowers and S. simplex has 7-16 ray flowers. Some floras indicate that it is the differences in the hairiness of the plants leaves or stems or inflorescence or the shape of the inflorescence.

    There does seem to be agreement that the basal leaves and petioles of S. multiradiata have (or often have) hairy margins, i.e., they are ciliate margined, whereas those of S. simplex are glabrous. The other point of some agreement is that the phyllaries of S. multiradiata are "unequal to almost equal" in length, but those of S. simplex are "strongly unequal".

Solidago multiradiata
Solidago multiradiata (Rocky Mountain Goldenrod)
Asteraceae (Sunflower Family)

Foothills, montane, subalpine. Openings, woodlands. Summer.
Kilpacker Trail, July 22, 2004.

This is a very common plant of open forests and mountainsides.  Because it often grows in small, dense patches and has numerous small flowers, it can give the impression of a very small fuzzy-top shrub.  It grows to over two feet tall, but plants are more commonly about a foot tall.

This is the most common of several Solidagos in the Four Corners area. As discussed above, there is little agreement in floras about how to distinguish this species from the very similar S. simplex (shown below), but several characteristics seem to be agreed on: First, both S. multiradiata and S. simplex are distinguished from a number of other Solidagos by their rounded arrangement of flower heads (rather than arched and one-sided, see Solidago velutina). S. multiradiata can then be separated from S. simplex by its mostly glabrous (without hairs) leaves; and by its numerous (usually 13) ray flowers; and by the nearly equal length of its phyllaries.

The first specimen of this plant was collected in eastern Canada either in 1765 by Moravian missionaries in Labrador or by Joseph Banks in Newfoundland and Labrador in 1766.  Aiton named the plant in 1789. "Multiradiata" refers to the "many ray flowers".

Solidago multiradiata
Solidago multiradiata (Rocky Mountain Goldenrod)
Asteraceae (Sunflower Family)

Foothills, montane, subalpine. Openings, woodlands. Summer.
Colorado Trail above Roaring Fork, July 26, 2004.

You can just about count the 13 ray flowers. While humans are concerned with such trivia, insects know what to look for and appreciate.

 

Solidago simplex

Solidago simplex

Solidago simplex

Solidago simplexSynonym: Solidago spathulata. (Sticky Goldenrod)
Asteraceae (Sunflower Family)

Montane, subalpine, alpine. Meadows. Summer.
Above: Wildcat Canyon Trail, August 27, 2007.
Left: Haviland Lake Trail, June 28, 2004.

This Solidago is widespread from Alaska down the Rockies to Mexico to Virginia to Quebec.  It grows from an inch tall in tundra to a foot-and-a-half tall in more hospitable environments.  It is usually shorter than S. multiradiata and has about eight rays per flower head whereas S. multiradiata has about thirteen.  Both have small, clustered, very bright golden yellow flowers giving plants a very soft, fuzzy appearance.

"Simplex" is Latin for "simple".  The plant was first collected for science by Humboldt, Bonpland, and Kunth near Santa Rosa, Mexico and was named and described by Humboldt in 1820.

Solidago simplex
Solidago simplex.  Synonym: Solidago spathulata. (Sticky Goldenrod)
Asteraceae (Sunflower Family)

Montane, subalpine, alpine. Meadows. Summer.
Haviland Lake Trail, July 23, 2005 and Wildcat Canyon Trail, August 27, 2007.

S. simplex usually has about 8 ray flowers but can range from 5-11 ray flowers (or even to 16, according to the Flora of North America). Its very similar cousin, S. multiradiata, often has about 13 ray flowers with a range given as 12-18.

The phyllaries of S. multiradiata are nearly equal in length, those of S. simplex are of very different lengths. Below, I outlined the tips of six phyllaries in red.

                          Solidago simplex                

Solidago simplex
Solidago simplex.  Synonym: Solidago spathulata. (Sticky Goldenrod)
Asteraceae (Sunflower Family)

Montane, subalpine, alpine. Meadows. Summer.
Haviland Lake Trail, July 23, 2005.

Solidago simplex
Solidago simplex.  Synonym: Solidago spathulata. (Sticky Goldenrod)
Asteraceae (Sunflower Family)

Montane, subalpine, alpine. Meadows. Summer.
Haviland Lake Trail, July 23, 2005.

The very lowest leaves are often toothed on their edges and have distinct petioles (lowest arrow).

As leaves are added they become smaller, smooth on their edges, and sessile.

Lower leaves are ample and generally spatulate; upper leaves are smaller and narrower.

Leaf tips are sometimes said to be obtuse to rounded, but as is evident from this photograph, they can also be acute.

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 Solidago multiradiata

Range map for  Solidago simplex