For many years I mistakenly identified the species shown on this page as Penstemon caespitosus, but it is now generally agreed that P. caespitosus does not grow in southwest Colorado. The species shown below is Penstemon crandallii. The two species are very similar. In fact, in at least one botanical key (Komarek's Flora of the San Juans) the species shown below keys to Penstemon caespitosus. In addition, several herbaria have plants from southwest Colorado labeled as Penstemon caespitosus; Mesa Verde National Park (in southwest Colorado) has Penstemon caespitosus on its plant list; and some range maps show P. caespitosus in southwest Colorado.

      Expert botanists Craig Freeman, Noel Holmgren (Intermountain Flora), Stanley Welsh (A Utah Flora), Bill Weber (Colorado Flora), Heil and O'Kane (Flora of the Four Corners Region), Bill Jennings, and Robert Nold (Penstemons) all agree that P. caespitosus does not occur in southwest Colorado.

      Though almost all experts agree that our southwest Colorado species is P. crandallii, William Weber rejects that identification and includes P. crandallii (and P. teucrioides and P. retrorsus) within P. caespitosus. But since Weber, as others, indicates that P. caespitosus occurs only in counties west and north of Gunnison County, Colorado, that leaves nothing in Weber's Colorado Flora to identify the species shown below.

Click to read about Penstemons.

Semi-desert, foothills, montane. Openings. Spring, summer.
Western Uncompahgre National Forest, May 31, 2013 and
Near Lone Mesa State Park, June 15, 2016.

Penstemon crandallii is, in the words of Penstemon expert, Craig Freeman,

"bewilderingly variable, and I’ve seen specimens referable to variety crandallii and variety glabrescens from Dolores, La Plata, and Montezuma counties.  Variety procumbens, a distinctive element in the complex, occurs only in Gunnison County as far as I can tell.  In Colorado, I also recognize another fairly distinctive variety, var. ramaleyi....

Specimens of P. crandallii from Montezuma County often are difficult to assign unambiguously to variety, but the species itself is readily distinguished from P. caespitosus in the field.  Stem and leaf pubescence is highly variable in the two species, so the most reliable character is the calyx lobe margins.  They are herbaceous or very narrowly scarious [not green; thin, dry, and membrane-like in texture] proximally [toward the base] in P. caespitosus, and broadly scarious proximally in P. crandallii.  The flowers also generally are larger and less strongly compressed laterally in P. crandallii compared to C. caespitosus." 

From several floras I have put together more distinguishing characteristics:

The leaves of P. crandallii are 1-2.8 cm long and 1.5-3.4 mm wide. Those of P. caespitosus are just .4-1 cm long and 1-4 mm wide.

The leaves of P. crandallii tend to be glabrous, at least apically; those of P. caespitosus are seldomly glabrous, more usually varyingly hairy.

The inflorescence of P. crandallii is secund (flowers tend to grow to one side). The inflorescence of P. caespitosus is spike-like.

One might also have trouble distinguishing between Penstemon crandallii from Penstemon linarioides, both of which commonly occur in southwest Colorado. The two look quite distinct from one another when you see photographs of them (see P. linarioides), but they are easily confused in the field, especially before flowers appear: the two species bloom at about the same time; their flowers are small, shades of blue, and tubular; their leaves are narrow and short; and they both grow in open, sunny areas of the foothills. But even without going into detailed botanical analysis, one can learn to separate the two species:

P. crandallii grows in spreading mats just a few inches tall with flowering stems sprawling along the ground; P. linarioides grows upright to eight inches tall in a rounded mound and its flowers are at the tip of upright stems.

P. crandallii has bright green leaves; P. linarioides has sage green leaves.

Flowers of P. crandallii are usually darker shades of purple; flowers of P. linarioides are usually lighter shades of blue and white.

Penstemon crandallii was first collected by Charles Crandall, University of Illinois Professor, near Como, Colorado in 1897 and was named and described by Aven Nelson in 1899. Click for more biographical information about Crandall.

Semi-desert, foothills, montane. Openings. Spring, summer.
Near Lone Mesa State Park, June 15, 2016.

The staminode (the sterile stamen) is densely golden to golden-yellow and it does not protrude from the throat. The staminode of P. linarioides is hairy just near its tip and may be exserted.

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 Penstemon caespitosus

Range map for Penstemon crandallii