Observations on Penstemon clutei, Coconino National Forest
Greg Goodwin Wildlife Biologist September 1979
Goodwin, Greg. 1984. Bulletin of the American Penstemon Society 1984 43(1) 26-31.
Penstemon clutei is a robust, pink-flowered herb that is only found in the vicinity of Sunset
Crater, Coconino County. It grows on volcanic cinder from 6500 to 8500 ft. elevation in
ponderosa pine forest. Eight of the localities are on Coconino National Forest north of
Flagstaff near Sunset Crater. The other locality is in Sunset Crater National Monument.
Penstemon clutei was listed as a Category 3C (delisted because more common than
previously thought) by the U.S. Fish and Wildlife Service in the 1980 Notice of Review. It is still
listed as a sensitive plant with the U.S. Forest Service. Because the plant is locally abundant and
only occurs in a small area that is mostly on Coconino National Forest, the Forest Service has
assumed the management and responsibilites for this endemic plant. It should be monitored and
considered in management plans for the area.
During August and September a field survey was conducted of the cinder hills area
northeast of Flagstaff for the proposed endangered plant, Penstemon clutei. This species is
endemic to the cinder hills area and is known only from near Sunset Crater National Monument.
Penstemon clutei is a large robust beardtongue with bright showy deep pink flowers. It is an
ecologic endemic (Daubenmier, 1978) having evolved strict habitat requirements. Only the very
limited area of the cinder hills can meet these special requirements. A ground search in the area
found this beardtongue in several discontinuous populations surrounding Sunset Crater.
The general relief of the cinder hills area is a varied pattern created by numerous volcanic
cones, lava flows, and broad, flat valley-like areas between the cones. The soils in the area are
well defined, however, they are covered with at least 8-10 inches of raw volcanic cinders (Patton
and Meurisse, 1972). The bare raw cinders constitute a relatively widespread blanket of fresh
black and red cinders composed of alkali olivine basalt. This material is a recent basalt
pyroclastic sheet from the eruption of Sunset Crater in 1064 AD (Moore and Wolfe, 1976). The
cinder hills area is part of the San Francisco Volcanic Field and the numerous cinder cones
present here make it unique as one of the more recent volcanic fields of the continental United
States.
The cinder hills area is predominately a ponderosa pine forest, with scattered pinyon pine
and Utah juniper occurring in rather open stands
At lower elevations on the east side, the area is predominantly a pinyon-juniper woodland.
Understory vegetation found in ponderosa pine stands on volcanic cinders differ considerably
from that found on nearby residual soils. Total plant cover is much lower and the herbaceous
flora more depauperate. Stands have little advance pine regeneration and pioneering shrubs such
as Fallugia and Chrysothamnus assume much more importance in these xeric areas.
2
The species most commonaly associated with P. clutei are apache plume (Fallucia
paradoxa). rabbit brush (Chrysothamnus spp.), beardtongue (P. barbatus). raullen (Verbascum
thapsus). and blue gamma (Bouteloua gracilis).
All populations were found in open pine stands at elevations between 6,500 to 8,500 feet on
relatively bare cinders which had virtually no soil accumulation (Table 1). In some areas needle
cast constituted as much as 50-60 percent ground cover with generally less than 30 percent
vegetative ground cover.
The cinder hills area falls within the Cinder Allotment which is now formally closed to
livestock grazing. The last grazing on the allotment occurred in 1969. Some wildlife use in the
area was detected, however, it is having no effect on the species.
Penstemon clutei is rather common in a small area on the east side of O'Leary Peak (Sec. 1
T23N, R8E). The population extends along the west side of Forest Road 546 for approximately
1/2 mile. This area has a large amount of apache plume and has had some past logging
disturbance. There was some reproduction, however, only four seedlings could be found in a 100
x 100 feet sample area.
The population south of Haywire Crater appears to be in good condition. Plants are
scattered across two general areas (Sec. 22 and 26, T23N, R9E) along Forest road 244. A total of
23 mature plants were counted in an area 100 x 100 feet and an estimated 45-50 seedlings were
found in the sample area.
The population on the south side of Pinnacle Crater (Sec. 31, T23N, R9E) is small and is
presently being severely impacted by off-road vehicle use. Little Cinder Basin and the
surrounding cones are receiving very heavy use by ORVs. Large groups of people are camping
around Pinnacle Crater and along Forest Road 777 between the Crater and Cinder Lake. This
small population will eventually be eliminated by the heavy ORV and dispersed recreation use of
the area.
The population near Cinder Lake occurs in a relatively flat open area extending along both
sides of the road. Mature plants were counted in a 100 x 100 feet sample area for a total of 40;
only 15 seedlings were found. This area is very open and has little understory vegetation, the
most common species being Penstemon clutei.
3
The largest population of P. clutei is that which extends from the west side of Sunset Crater
National Monument west and north up to near the summit of O'Leary Peak. Part of this
population was burned in November, 1973 when Burnt Fire burned a large area west of the
Monument. The plants in this area are very vigorous and reproduction abundant. Stems on these
plants reach as high as 3-4 feet. As a result of the fire relatively dense pole-sized stands of
ponderosa pine were opened up and all litter accumulation burned. The bare cinders now support
growth and reproduction rates that are considerably higher without competition.
Eggler (1966) reported that there was not evidence that plant succession was taking place at
Sunset Crater. It does appear, however, that after a fire succession occurs as species invade the
bare cinders and a ponderosa pine forest develops. Penstemon clutei is one of the pioneering
species. All species found in the burned area were invaders, Verbascum thapsus. Amaranthus
ssp., Sal sol a kali. and Mentzelia ssp.
McDougal (1973) reported that Penstemon clutei occurs at elevations near 7,000 feet,
however, this population extends up the south side of O'Leary Peak to near 8,600 feet. Plants
become increasingly less abundant at higher elevations occurring only in very open unshaded
areas. The optimum growth and abundance seem to occur below 7,500 feet elevation. Common
species associated with this beardtongue at 8,000 feet are Fallagia paradoxa, Pericome caudata.
Sitanion hystrix. Ribes ssp. and Senecio ssp.
A large part of the cinder hills area was surveyed for this species. No plants could be found
south of the Transwestern gas line or in the Maroon Crater area. The area adjacent to Strawberry
Crater was also examined but no plants found. The floristic composition and overall
physiographic conditions at Strawberry Crater are similar to those areas that contain Penstemon
clutei except the area lies at 6,200 feet elevation and 1s a pinyon-juniper woodland.
Penstemon clutei is wide ranging within the limited habitat afforded by bare volcanic
cinders and does not meet the criteria for a threatened or endangered species as defined by the
Endangered Species Act. The only substantial threats to this species are protection from fire and
ORV use. However, the area
east of the 345K transmission line is now in a proposed let-burn area. Plants also seem to be
somewhat resistant to trampling if it is only occasional and does not expose the root system from
accelerated movement of cinders.
MANAGEMENT RECOMMENDATIONS
1)
Areas of Penstemon clutei habitat need to be subjected to fire on a periodic basis.
Prescribed burning is obviously a very valuable if not critical management tool for this species.
2) ORV use has the potential to destroy large amounts of habitat and the actual existing
populations. Already large areas of the cinder hills show evidence of ORV use. The ORV
policy regarding the cinder hills needs to be expanded and strictly enforced. The status of
Penstemon clutei could rapidly change if ORV use is not more effectively managed.
LITERATURE CITED
Daubenmire, R.
1978. Plant Geography. Academic Press, 338 pp
Eggler, W.A.
1966. Plant Succession on Recent Volcano, Sunset Crater Plateau, 38: 81-96
McDougal, W.B.
1973. Seed Plants of Northern Arizona. Museum of Northern Arizona. 594 pp
4
Moore, R.B. and E.W. Wolfe
1976. Geologic Map of the Eastern San Francisco Volcanic Field, Arizona. USGS Map
1-953, Misc. Inves. Series.
Patton, W.W and R.T. Meurisse
1972. Soils Report, Cinder Hills Area, Elden Ranger District, Cocom'no National
Forest.
NOTE: Elona Ballou, one of our members in North Las Vegas, NV, learned that one of her
forestry professors was working on the effect of perscribed burning on P. clutei. At her request
he gave her some names of Forest Service personnel who sent her the article printed above.
TABLE I. SITE DESCRIPTION OF PENSTEMON CLUTEI POPULATIONS IN THE
CINDER HILLS AREA
Tree Canopy Basal
Coverage Area Location
Elevation Slope
(Ft.)
{Sq. ft.)
Haywire Crater 6,500
10 NE
10
40 Sec. 26, 21, 22 T23N, R8E
O'Leary Peak (East) Sec. 1, T23N. R9E
6,500
10
NE
10
Pinnacle Crater Sec. 31, T23N.R9E
7,000
20
NVI
6
Cinder Lake
Sec. 7, T22N.R9E
6,700
5
O'Leary Peak
(South)
Sec. 3 T23N.R8E
8,500
50
NW
S
40
40
15
30
5
20
(%) Aspect
%