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GRAND CANYON NATURE NOTES
September 1934Volume 9, Number 6


FLORA OF GRAND CANYON NATIONAL MONUMENT

By Park Naturalist, Edwin D. McKee*


*Material obtained on a reconnaissance trip for the purpose of making general observations, studies and collections of the biological and geological features of the region made during the period of April 8 to 14, 1934.

The flora of the Grand Canyon National Monument represents several distinct plant associations, each of which is different and in contrast to that, with Saltbush predominating, along the approach road across the great alkaline plains to the northeast. The main groups of plants in the Monument are controlled principally by factors of soil and climate and for the most part are rather distinct in their constituents although gradational along their borders. They are listed by the writer as (1) the high mountain type, (2) the valley wall type, (3) the open valley type, (4) the inner canyon rim type, and (5) the lava bed type. In the first two of these, representing the high altitudes, plants are almost if not entirely the same as those found in corresponding life zones in Grand Canyon National Park to the east. In the lower two, many of the plants are of species unknown in eastern Grand Canyon, while the open valley type is intermediate in its status.

HIGH MOUNTAIN TYPE, REPRESENTED ON MT. TRUMBULL AND NEIGHBORING VOLCANIC PEAKS, ALTITUDE 6,250 - 7,500 FEET:

This type corresponds to the upper part of the upper Sonoran and to the Transition Zones as found on the Kaibab and Coconino Plateaus to the east and essentially all of its plant species are found in those areas. A few typically Canadian Zone species are found in sheltered places on the mountains.

List of conspicuous plants in lower part.
(c) - very common:

Manzanita



(c) Pinyon Pine - Pinus edulis
(c) Sagebrush - Artemesia tridentata
Gambel's Oak - Quercus gambelli
Live Oak - Quercus wilcoxii
Manzanita - Arctostaphylus pungens
Scarlet Bugler - Pentstemon torreyi
Mountain Mahogany - Cercocarpus sp.
Cliff Rose - Cowania stansburiana
Gooseberry - Grossularia sp.
Hollygrape - Berberis fremontii
Ponderosa Pine - Pinus ponderosa







List of conspicuous plants above spring, near top of Mt. Trumbull.
(c) - very common:

Stonecrop Elderberry - Sambucus sp.
(c) Gambel's Oak - Quercus gambelli
(c) Ponderosa Pine - Pinus ponderosa
Quaking Aspen - Populus tremuloides
Meadow Rue - Thalictrum sp.
New Mexico Locust - Rubinia neomexicana
Apache Plume - Fallugia paradoxida
Big Blue Pentstemon - Pentstemon
Wild Buckwheat - Eriogonum sp.
(c) Stonecrop - Sedum stenopetalum







VALLEY WALL TYPE, REPRESENTED ON BOTH SIDES OF TOROWEAP VALLEY, BROKEN WALLS OF SEDIMENTARY ROCKS, ALTITUDE 5,000 - 6,250 FEET:

This type corresponds closely to the upper Sonoran Zone as found on the Coconino and Kaibab Plateaus to the east, with essentially all of its species also found in those areas.

A few typically Lower Sonoran species are also found in this association on the more open slopes. Both because of a lack of time and because the flora was so similar to that of the National Park area, a rather incomplete list was made of this type.

Partial list of conspicuous plants:

Cliff rose

Rabbitbrush - Chrysothamnus sp.
Snakeweed - Guterrezia sp.
Cliff Rose - Cowania stansburiana
Mormon Tea - Ephedra viridis
Barrel Cactus - Ferocactus lecontei
Sagebrush - Artemesia tridentata
Cucumber Cactus - Echinocereus sp.
Leadbush - Lopagyrea argentea
Pinyon Pine - Pinus edulis
Utah Juniper - Juniperus utahensis







OPEN VALLEY TYPE, REPRESENTED IN TOROWEAP VALLEY - A WIDE FLAT PLAIN FILLED WITH ALLUVIUM, ALTITUDE 4,250 - 6,000 FEET:

Since this valley includes most of the area to be developed as an antelope range, its flora is of considerable interest. At the present time it is very badly overgrazed and includes a surprisingly small number of species. Indeed there are only four or five different plants that can really be considered common in this area.

Partial list of conspicuous plants.
(c) - very common:

Blue flax

(c) Sagebrush - Artemesia tridentatum
(c) Cholla - Opuntia sp.
(c) Bread-leaf Yucca - Yucca baccata
Narrow-leaf Yucca - Yucca baileyi
Saltbush - Atriplex canescens
Snakeweed - Guterrezia sp.
Pincushion Cactus - Mammalaria sp.
Hollygrape - Berberis fremontii
(c) Mormon Tea - Ephedra sp.
Blue Flax - Linum sp.
Red-stemmed Filaree - Erodium cicutarium
Evening Primrose - Oenothera sp. (upper end)
Thistle Poppy - Argemone sp. (upper end)











INNER CANYON RIM TYPE, REPRESENTED AT JUNCTION OF TOROWEAP VALLEY AND GRAND CANYON EXCEPT ON LAVA FLOWS. RED SANDSTONE AND SHALE OF THE SUPAI FORMATION. ALTITUDE 3,250 - 5,000 FEET:

This type is characterized by a peculiar mixture of fairly well developed Upper Sonoran species together with a great number of those typical of the Lower Sonoran Zone. Many of the latter are of species not represented farther east in Grand Canyon, even at lower altitudes, and others have attained a remarkably large growth.

The apparent excessively favorable conditions for the development of Lower Sonoran types in this area seem incongruous when it is considered that fairly large Pinyons, Junipers and Sagebrush occur mixed with these. From this it would seem evident that the temperature is not the principal controlling factor in this area. Probably a more favorable supply of moisture explains this phenomenon, however, no concrete evidence was obtained to substantiate this suggestion.

Specific example of plants illustrating the unusual conditions represented in this area are the Ocotillo and Creosote Bush, plants that have not been recorded from farther east in Grand Canyon, and the shrub Thamnosmia which in one place has actually developed into the proportions of a tree, 15 feet high and with a basal trunk diameter of 14 inches, looking strangely similar to a huge broom pointing skyward. The exceptionally great size of the Broad-leaf Yuccas and the rigidity of their leaves are also noteworthy local developments.

Partial list of conspicuous plants.
(c) - very common:

Pinyon Cone
(c) Live Oak - Quercus wilcoxii
Pinyon Pine - Pinus edulis
Utah Juniper - Juniperus utahensis
(c) Mountain Mahogany - Cercocarpus sp.
(c) Turpentine Broom - Thamnosma montana
Rabbitbrush - Chrysothamnus sp.
Century Plant - Agave utahensis
Yellow Mustard
(c) Indian Paintbrush - Castilleja sp.
(c) Broad-leaf Yucca - Yucca baccata
Narrow-leaf Yucca - Yucca baileyi
Beargrass - Xerophyllum tenax
Desert mallow





Cucumber Cactus - Echinocereus sp.
Gray Prickly Pear - Opuntia chloritica
Big Prickly Pear - Opuntia sp.
Paper Flower - Psiliostrophe sparsiflora
Sagebrush - Artemesia tridentata
Squawberry - Rhus trilobata
Creosote Bush - Covillia trdentata
Ocotillo - Founquieria spendens
Blue Flax - Linum sp.
Scarlet bugler Rabbitbrush - Chrysothamnus sp.
Desert Mallow - Sphaeralcea sp.
Wild Four O'Clock - Quasmoclidion
Phlox - Phlox caespitosum
Pincushion Cactus - Mammalaria sp.
Apache Plume - Fallugia paradoxida
Singleleaf Ash - Fraxinus anomala
Rock Rose - Petrophytum caespitosum
Scarlet Bugler - Pentstemon bridgesi
Evening Primrose - Oenotheria sp.
Devil's Claw - Martynia louisiana

(Some others which appeared to be different from any found in eastern Grand Canyon but which have not yet been identified, were collected.)

LOWER LAVA BED TYPE, REPRESENTED BY BASALT FLOWS FROM VULCAN'S THRONE AT LOWER END OF VALLEY INTO INNER CANYON, ALTITUDE 3,250 - 5,000 FEET:

This area, although representing about the same altitude as the preceding, is characterized by a very distinct plant association. Like the preceding, however, it contains many species not found in eastern Grand Canyon and many Lower Sonoran types which have attained exceptional size. Most noteworthy in the latter group are the Barrel Cactuses which grow to a height of four feet and the Chollas which appear in clumps, 25 to 30 feet in diameter and as high as a man. Since among the plants not known to the writer were several of the most common species, the following list loses most of its value until determinations make it possible to supplement the names of these.

Partial list of conspicuous plants.

(c) - very common.

(c) Snakeweed - Guterrezia sp. (most numerous plant in upper section.)
(c) A feathery plant not yet determined.
(c) A plant with bulbous leaves not yet determined. (Most numerous in lower section.)
Yellow Daisy - 3 species
Mormon Tea - Ephedra sp.
Barrel Cactus - Ferrocactus lecontei
Cucumber Cactus - Echinocereus sp.
Cliff Rose - Cowania stansburiana
(c) Sagebrush - Artemesia tridentata (common in section)
(c) Broad-leaf Yucca - Yucca baccata
Apache Plume - Fallugia paradoxida
(c) Indian Paintbrush - Castelliga sp.
Blue Pea
Cholla - Opuntia sp.
Loco - Astragalus sp.
Prickly Pear - Opuntia
Mesquite - Prosopis

Turpentine Broom Height 15 feet

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