Southwest Colorado Wildflowers, Apocynum

Precise identification of the two species shown on this page is difficult because the two species are quite similar in morphology and they hybridize (the hybrid is called Apocynum x medium and can include crosses with the third Apocynum species in the Four Corners area, A. sibiricum -- a species with sessile, cordate leaves). Intermountain Flora notes that the genus is "perplexing ... due to considerable range of variability, which can be inferred from the long lists of synonyms. [Edwin] Greene alone proposed more than 65 [names for the three species in our area.]"

Several characteristics, observable in the photographs below, help to separate A. androsaemifolium and A. cannabinum:

A. androsaemifolium flower petals are 3-4 times as long as the calyx, about 5/16" long; petals of A. cannabinum are 2-3 times as long as the calyx, about 3/16" long.

A. androsaemifolium flower petal lobes tend to reflex; petal lobes of A. cannabinum tend to be upright or horizontal.

A. androsaemifolium leaves tend to droop and be egg-shaped, and they are about twice as long as wide; leaves of A. cannabinum tend to be horizontal and they are about three times as long as wide.

A. androsaemifolium leaf petioles are attached to the stem in line with the attachment point of the petioles above them. A. cannabinum leaf petioles tend to be attached to the stem 90 degrees around the stem from the point of attachment of the petioles above them.

A. androsaemifolium seed pods are about twice the length of its leaves; seed pods of A. cannabinum are more than three times the length of its leaves.

Linnaeus named the Apocynum genus in 1753. "Apocynum" is Greek for "away dog", i.e., "dogbane". Extracts of the plant were used as poison to kill wild dogs.

Apocynum androsaemifolium (Dogbane)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Roaring Fork Road, July 7, 2006.

Drooping leaves and a pink corolla help to set this species apart from the next, but the two species (and A. sibiricum) hybridize making precise identification difficult. Generally this species is found on rocky, gravelly soils and the next along streams and washes.

In 1753 Linnaeus named this genus and species. In the following 150 years the plant endured dozens of name changes.

"Androsaemifolium" means "with leaves similar to those of the genus Androsaemum", a name once given to the genus that we now call "Hypericum".

Apocynum androsaemifolium (Dogbane)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Roaring Fork Road, July 7, 2006.

Apocynum cannabinum (Dogbane, Indian Hemp)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Lone Mesa State Park, July 2, 2008.

This is a fairly common but greatly overlooked plant even though it grows to about two feet tall in thick patches (from underground spreading roots). It has a very erect and open, airy growth pattern and tiny, but quite elegant white-to-pink flowers.

Linnaeus named this species in 1753. "Cannabinum" is Greek for "hemp"; the fiber of mature Apocynum cannabinum was used for cordage.

Apocynum cannabinum (Dogbane, Indian Hemp)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Lower Dolores River Canyon, May 17, 2004.

Apocynum cannabinum (Dogbane, Indian Hemp)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Lone Mesa State Park, July 2, 2008.

Apocynum cannabinum (Dogbane, Indian Hemp)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Piedra River Canyon, August 20, 2005.

Long, narrow seed pods emerge from the tiny flowers.

Apocynum cannabinum (Dogbane, Indian Hemp)
Apocynaceae (Dogbane Family)

Foothills, montane. Meadows, moist woods near streams, roadsides. Spring, summer.
Lower Dolores River Canyon, September 12, 2005.

Lemon-yellow fall color reveals Apocynum cannabinum plants which often go unnoticed during the summer.

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 Apocynum androsaemifolium

Range map for Apocynum cannabinum