An Ecological Survey of the Vegetation of the Dinosaur National Monument, Utah

Brigham Young University BYU ScholarsArchive

Theses and Dissertations

1957-01-01

An ecological survey of the vegetation of the Dinosaur National Monument, Utah

Stanley L. Welsh Brigham Young University - Provo

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BYU ScholarsArchive Citation Welsh, Stanley L., "An ecological survey of the vegetation of the Dinosaur National Monument, Utah" (1957). Theses and Dissertations. 7999. https://scholarsarchive.byu.edu/etd/7999

This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. AN ECOLOGICAL SURVEY OF THE VEGETATION OF THE

DINOSAUR NATIONAL MONUMENT~ UTAH

STANLEY L. WELSH : /

A THESIS PRESENTED TO THE FACULTY OF THE DEPARTMENT .

OF BOTANY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS

FOR THE DEGREE OF MASTER OF SCIENCE

223834

BRIGHAM YOUNG UNIVERSITY r ~,) 1957 This thesis by Stanley L. a Welsh is ac.cepted in it• present farm by the Thesis Committee as satisfying the Thesis requirements fsr the degree of Mastel' of Science. ----- 1957.

Thesis Committee ACKNOWLEDGEMENTS The author wishes to express his gratitude to all those who have helped to make this work possible. Special thanks are extended to Dr. Earl. M. Christensen _of the Brigham Young University .for his guidance and critical assistance in the preparation of this paper. The author is irui.ebted to Dr. B. F. Harrison of the Brigham Young_University for the identification of the grass.es, to Dr. William A. Weber of the University of Colorado for the use :of that institutions herbarium and for his kind interest and co-operation in the identification of the Astragali and numerous other plattl:s, and to S. F •. Blake, Beltsville, Maryland for the prompt identification :of a doubtful composite.

For aid in the preparation of the section on geology the author is grateful to G. E. and B. R. Untermann, Directors of the Utah State Museum at Vernal, Utah, and to Dr. Norman C. Williams of the Univers.ify'. of Utah.

The c:0-operation of the U.S. National Park Service and especially that of Jess Lombard was greatly appreciated. Without the permission and assistance of the Park Service it would not have been possible to collect plants within the :Monument.

The author is als,o indebted to Douglas Chew for the use of the cabin on Blue Mountain on various occasions. TABLE OF CONTENTS Pag,e ACKNOWLEDGMENTS...... • • • • ii

INTRODUCTION • • • • • 0 • • • • • • • • • • • • • • • 1

Statement of the Problem Review of Literature Geographic Descriptien of the Dinosaur National Monument Geology Climate Field Methods

RESULTS ...... • • • 0 • • • • • • • • • • • • • 14 Che:c:k List Vegetative Map Plant Communities ,0£ the Geological Formations DlSCUSSION • • • • • • • • • • ...... • 40 Shale Fmrmations Sand.stone Fermati&ns Selenium Vegetation Zmies .Diatur bance

·SUMMARY • • • • • • • • 0 • 0 . . . . • • • • . . • 46

APPENDIX ••• ...... • • • e • • • • • • . . . . • 48 List of Vascular Plants ,with-Ecological Annotation

REFERE.NCES • • • • • • • • • • • • .. • • • • • • • • • 84 INTRODUCTION

Statement of the Problem

The present work is a general survey of the vegetation of the Utah pl)rtion of the DinosaUl' National Monument with special emphasis on some of the ecological aspects of the area. The vegetation ranges from xerophytic plant communities of the Lower elevations to mesophytic communities of the higher elevations. Hydrophytic plant communities are also present to a limited extent along .the Green River and where seeps or springs arise. Soils vary from fine clay to coarse gravel. The dividing lines between formations is often marked by extreme differences in s.oil type. During the author'.s first collecting trip into the Monument in April 1955 the possibility of c.orrelations between geological formations and vegetation was suggested by the occurrence of certain plant species on some of the formations. The presence of a well defined geological section in a relatively short distance makes it possible to determine if such correlations exist.

Review of ·LiteTature

The most significant botanical study of the vicinity of the monument was that made by Edward H. Graham (1937). In his work Graham described many plant ass.ociations and listed all species collected. In t 1938 Stoddarl described range conditions in the Uinta Basin. More :recently Bradley (195,0) wrote a master's .thesis, at present unpublished, on the vascular plants of Moffat County, Coltn~ado. The Colorado portion .r,f the Monument is in Moffat County. Her work includes a short discussion and a check list. lt has been noted by several writers that plants are indicators of certain s.oils and geological formations. Jeane.Etienne Guettard n-oted the existance of such indicator plants in .the 1750's during his travels in France and western Germany -(Fenton and Fenton, 1952, p. I 28). Many studies carried on in the United States indicate a close rel- ationship between certain plants and Geological formations. Cuyler

l 2

(1931). showed the existence -of such a correlation between the geological formations and plant communities around Austin,. Texas •. Beath, et. al •. (1914, 1935, 1939, 1940, 1941), Byers {1935), Knight and Beath (1937), and Beath (1943) have demonstrated the correlation between seleniferous-.soils and vegetation. More recently Cannon (1952} noted the c:0rrelat:ion between uranium - vanadium deposits and vegetation. Plants have long been known to be indicators of agl'icultural land (Sampson, 1939 and· Fireman, et. al., 1952). Graham (I 937) noted the existance of endemic species .of plants on the Green River shale formation in the Uinta Basin. In working with the Shale Barrens of Virginia, Platt (I 951} listed eight spec;:ies of plants as endemic to the Brallier shale. Lindsey (1951) found plants in a volcanic region of New Mexico to be restricted to certain types of substrate. Some soils, such as the serpentine s.oils, are well kn:own for the endemic species that occur on them {MaJts.on, 1946).

Geographic· Description of the Dinosaur Nat~onal Monument

The Monument consists .of about 2.00, 000 acres partially in Utall, and partially in Colorado. The Utah portion is the smaller (about 75, 000 acres} and is partly on the s.outh flank of the Uinta Mountains and partly in the Uinta Basin. The Uinta Basin is a structural down- warp which occupies part of northeastern Utah and northwestern · Calor ado. It is bounded on the north by the Uinta Mountains, on the west by the Wasatch Mountains, on the south by the Tavaputs Plateau, and on the east by the mountain ranges in Colorado, whose western drainage is ultimately the Gr·een Riv~r via the White River. The Utah portion of the Monument lies approximately along the course of the Green River and includes the west slope of Split Mountain. (See plate I). Where the Green River enters .the Utah portion the elevation is approximately 5, 150 feet. In the next twenty-one miles the river falls 400 feet and leaves the southern boundary :of the Monument at an elevation :of 4, 750 feet. On the south and east sides of the river the land rbes abruptly to an elevati&n of more than 7, 500 feet on the Blue Mountain and Yampa Plateau:s (Topographic map page 19) •. In some of the canyons the rise is practically vertical while at Island and Rainbow Parks a Jew foot- hills border the steep mountain side. The north and west side of the 3 river is one of contrast with mountains rising abruptly from the river- bed and some open relatively flat places where the Gr:een RiveT has formed small flood plains adjacent to large meanders. All drainage in the Me>nument is into the Green River. There are few permanent streams in the a:rea; the major exceptions being Jones Hole Creek, Sage Creek, and Orchard Creek.

Geolo5y "The geological structure is well reflected in the relief features of the Monument and consist of several minor synclines, anticlines, and benchlands adjacent to faults which :0ccur along the flanks of the eastern portion of the Uinta Mountainstt '(Untermann and Untermann, 1954, p. 7). The Split Mountain area consists of a rather abrupt anticline that has been eroded ex.p:osing a sequenc.e of older underlying formations, th-e oldes.t being in the center of the anticline and the youngest on the outside. The expnsed formations .have eroded forming a series ,of concentric ridges and valleys (Plate 1). North of the Split Mountain is a syncline where the strata dip to the north into the axis .of the syncline and then rise onto the s.outhern flank of the Uinta Mountains. The Blue Mountain is a continuation of the ·Split Mountain and Jensen anticlines. Major faults .occur north of Split Mountain, in the Island Park area,, and north of Squaw Mountain. These faults have caused the formations to be tipped up vertically in the Island Park area and to be offset in other plac~s. The Green IHver shows definite signs .that at one time it was an old meandering stream. Untermann O 954, p. 8) says, "The earlier mature topog~aphy has been re-elevated resulting in the rejuvenation of the meandering .streams which have been encised and entrenched. Thus the tops of most of the mountains and hills are broad and well matured ••• while the canyons, commonly 1, 000-2, 500 feet deep, are still youthful and are actively abrading (Plate Z)o A number of parks between canyons, however are more mature and are developing a new set of n:ieanders as a result of local base leveling. 11 In many areas the geological formations ue covered by a deep layer of alluvium which has been derived from the higher land masses. The geological eras represented in the M.onument range from Paleozoic to Cenozoic. The periods :represented range from Cambrian Green River 4

Plate 1- View of Split Mountain from Blue Mountain.

Plate 2- Whirlpool Canyon from Harper's Corner. 5 to Quaternary, but the Devonian., Silurian, an.cl 0J"dovician are missing .in the eastern Uinta Mountain .area (Untermann, G~E., personal com- municatian) • . The formations -will be described. in .s,equence from oldes.t to youngest.

CAMBlUAN SYSTEM . i..dore formatiQn

Untermaim.·{1954, p. 25) says, "• • • the cambrian beds are exposed in the deeper canyons and along some of the faults. Such an outcrop occurs in Jones Hole and adjacent Whirlpool Canyon. Here. the formation consists .of approximately 450 feet of thick- to thin- h.edtied, white and red quartzitic sandstones, quart.dtes and green to r·ed shales. n

MISSISSIPPIAN SYSTEM Undifferentiated

Unterma.tm ·{I 954, p. 27) says, "The Mississippian in Dinosaur Nati.anal Monument consists of Madison limeston.e and d.elomite flower Mississippian) at the base fellowed by .cherty and sandy limestene, ®h,mite and marls.tone heds which may be equiv~lent to the Deseret a:n.d Humbug formations ·(upper Mississippian)." For the purposes of this paper the&e formations ar·e considered as a ~ingle unit. The author ha, collected enly on .the upper portion of this group. Accord- ing to G~ E •. Unter·mann (personal communication) the Des·eret formation may b.e tlte only one pres.ent in the Split Mountain area. The upper portion weathers into a light yellow to gray slab rock which forms talus slid.es al.eng the very ateep slopes. In the middle of the Split Mountain Gorge the nearly vertical cliffs aleng the ·Green River are :in this formation.

PENNSYLVANIANSYST~ Morgan fo.rmation The Morgan is a rather complex formation. This formation is hest

Weber formation

The Weber formation consists of a uniform light yellow sandstone about 1, 000 feet in thickness. It is this massive formation that caps Split Mountain. On the SDuthern flank :of Split Mountain the formation is cut by box canyons having vertical walls (Plates 1 and 4). This feature produces the very rugged appearance of the mountain. Untermann -(1954, p. 36) states, "The poorly cemented and highly jointed nature of the Weber accelerates its erosion, producing char- acteristic deep steep-walled gorges and resulting in extremely rough top:ography." The soil resulting from this formation is a relatively uniform light-yellow sand.

PERMIAN SYSTEM

Park City formation

The Park City formation is a thin formation in the Monument (54 feet), but because of the nature of the g.eology of the area, it forms an imp.ertant part {Geologic Map p. 21 ). Along both the north and south flanks of Split Mountain it forms "flaf;iron.s" between the hollows cut into .the underlying Weber formation. On the west side of Split Moun- tain, where the slope is more gradual, it forms an extensive expos.ure. The soil on the formation consists .of particles of various size. The .size ranges from fine sand to large flat boulders.

TRIASSIC SYSTEM

Moenkopi formation

The Moenk.opi formation is composed of a sequence of coarse brick-red sandy siltstones. The Moenkopi is rather easily weathered and the major drainage systems on the southern side of the Monument are cut in it. The main drainage pattern consists of the main subse- 7 quent stream cours:e following the curvature of the formation with lat- eral ohsequent and-resequent washes entering at right angles to the main water c.ourse •. The soil from this formation consists of a relativ ... ely fine brick-red sand. In many places small ridges of more resistant material alternate with saddles and depressions at right angles to the strike of the formation. More resistant layers of rock in the formation form hogbacks that run parallel to the strike.

Shinarump conglomerate

The Shina.rump conglomerate is a resistant formation composed of csarse quartzitic sandstone containing translucent quartz pebbles. Wherever the formation is exposed steep much-fractured hogbacks are present. The hogbacks break into large angular boulders that fall on the lower side of the formation onto the underlying, more easily weathered, Moenkopi. The soil produced by weathering is a coarse light colored sand containing few- to many rounded quartz pebbles.

Chinle formation

The Chinle consis.ts chiefly of a coarse red sandy shale and silt- s.tone. This formation weathers easier than the formations above or below it and forms saddles and depres·sions between the Navajo sandstone (Jurassic) and the Shinarump (Triassic). The Chinle weathers .to a coarse red sand, but the soil cover is scant and thin layers .of rock crop out in many places. The drainage on this formation follows the strike.

JURASSIC SYSTEM

Navajo sandstone

The Navajo sandstone consists of a thick layer of cross-bedded sandstone. "The large and flowing cross-beds found in this formation demonstrate its eolian origin" (Stovall and Brown, 1954, p. 325). It weathers .to form a fine yellow~ to light red sandy soil. In some places it is cut by vertical walled canyons having sandy floors. The surface of the formation is covered with rounded baren knobs and sandy depressions. The surface of the knobs is cut by small V-shaped channels which form a reticulate pattern on .the surface of the rock. In some places, such as Orchard Creek Draw and in the Horse Trail Canyon drainage, springs arise from the Navajo. 8

Carmel formation

The Carmel fo.rmation is, for the most part, a rather coarse, red, sandy shale. This shale weathers more easily than the -Entrada sandstone above it and the Navajo sandstone beneath it atid forms saddles and depressions between th-ose two ..formation.s. The resulting soil is an :easily er·oded .red sand. The drainage pattern on this formation us.ually follow.a the strike.

Entrada sandstone

tJntermann {1954, p. 50) says, "The sandstones of the Entrada are light gray to buff, locally reddish, and of medium fine- to medium- gl"ained clear quartz varieties." The soft strata weather more easily leaving the more resistant strata e:ropping out in parallel strike ridges. Thus, sandy flats and depressions are common on this formation. The soil res.ulting from this formation i.s a light yellow sand.

Curtis formation

In his discussion .of the Curtis formation, tJntermann (1954, p. 51) says, "This series .of thin=bedded sediments consists of ••• fossili= fero.us sandstones, shales, and oolitic sandy limestoneso The formation can be roughly divided into two parts. The lower third is composed of medium to coarse grained greenish-gray or brownish glauconitic sandstone which is frequently quartzitic with a 'sugary' texture." The ·Curtis weathers easily and locally forms abrupt ridges trending at right angles to the strike. The soil produced from this .formation is a lo.ose light-tan colored sand having a steep angle of repose.

Morrison formation

The Morrison is remarkable for dinosaur remains, for its variegated colors, for the complexity of its deposition, anq. for the lenticular, er lenslike, character of its beds" (Stovall and Br,own, 1954, p. 32.7).. The Morrison is composed of a poorly consolidated shale interbedded with sandstone lenses. The lenses .range in thickness from a few inches to several feet. The shale weathers into a variegated clay of red, white, green, and maroon colors. The sandstone weathers into rough angular g:ravel held together by a clay matrix.. The formation weathers into steep rounded hills that are covered with a hard clay 9 crus.t. Accoi-ding to Untermann (I 954, p. 54), the formation is high in silica and salts. In .some places white salts ·appear at the surface. When water strikes this formation there is. very little surface- run.- off. Most of the water a.inks into c.revasses, percalates downward, and reappears at the surface near the bas.e of the slope. CRETACEOUS SYSTEM

Dakota sandstone

The Dakota formation is an easily eroded sandstone. In s.ome places it is more resistant and forms hogbacks but not as commonly as the more resistant Fr·onti,er sandstone which it resembles. The s.:0il resulting from the weathering of the Dakota is a light yellow sand.

Mowrx shale

The Mowry shale is easy to identify because of the form of the sail particles produced by weathering. It weathers to a blue-gray or silver color. The color is produced by the reflection of light from the thin flat rock fragments cove-ring the surface of the formation. The a.oil con.sis.ts of thin flat rock fragments with a matrix of sand and clay. In many places the soil cover is scant or missingo The shale is in thin lens.es and in aome places layers of clay f.erm bands between thes:e. The formation is high in silica which is thought to have been derived from the alteration n£ volcanic ash fReeside and Weymouth, 1931, p. 2). At the bas.e of this formation (between the Mowry and Dakota fermations) seeps arise. This is especially true along the Island Park-Vernal road north of the Monument. Small swampy areas surr·ound the seep.so

Frontier sandstone

The Frontier is capped by a .resistant sandstone member. This s.ands.ton.e is fractured and in s.ome places these fractures from crevasses which are filled with soil. The formation stands at a rather s,teep angle and forms one of the series of hogbacks so notable on the southern sid.e of the Monument (Plates 11 and 12)., In the Island Park area this .formation is essentially horizontal and is covered with an accumulation .0£ a.oil. The lower part of the formation is easily weather·ed and yields a light _yellow colored sand having a steep angle of 10 repose. In many places .the s,oil eroded from the Frontier partially covers the Mowry shale.

Mancos shale

The Mancos shale is, for the most part, composed of a black shale that is easily weathered into a yellow to dark gray clay. The snil that is formed is fre-quently very saline and in s,ome areas patches of ..,.hite salts appear at the surface of the gr:ound. This formation erodes to form rather steep, but r:olling hills. The Buckskin Hills east of Vernal are in this formation. The conspicuous rounded gray.black hills at the southwest corner ·of the Monument are also a part of this formation.

TERTIARY SYSTEM

Bishop conglomerate

In several parts ef the Monument there is a formation consisting of an aggregation~ef different sized and different colored cobble rocks. This is .the remains of a pl)-orly-s:orted conglomerate deposited during _the Tertiary {Untermann and Untermann, 1954, p. 65). According to Norman C •. Williams ·{personal communication), the Bishop was formed as a pediment gravel on the old surface, known as the Gilbert Peak :surface, into which the present drainage has been, with pauses, in- cis.ed. :Remnants of the Gilbert .Peak surface are widespread in the Uinta Mountains and except for the higher elevations are capped by the Bishop conglomerate. The Bishop is best developed on the sloping elevated ground to the north of .Rainbow Park, but is found capping many f.ormat1ons in all parts of the Monument.

QUATERNARY SYSTEM

Alluvium

The major deposits of alluvium occur in the Island Park-Rainbow Park area. However, deposits of alluvium are fouad in almost every ravine and at the m:ouths of small drainages where alluvial fans are produced. The alluvium is of sever al types, depending .on its origin. Sand is the major alluvium covering the Moenkopi formation eas.t of the Green Tiver and ins.mall areas at the head of Red Wash. Sand is 11 also present as the alluvium in Beaches draw and along the Green River. The soil on the Blue Mountain Plateau consists of a dark sandy loam. At the north and West sides of Rainbow Park and overlaying the Mancos shale to the south of the Headquarters area the soil is a heavy clay.

Climete

Climatological data for the Monument are incomplete. Records of temperature have not been gathered and precipitation records have been kept only since 1948. However, inferences may be drawn from the records of the Jensen and Vernal weather stations. These stations are the only ones in the vicinity of the Monument. The Jensen station (elevation 4, 739 feet) is located approximately seven miles south of the Monument (elevation 5, 080 feet), and the Vernal station (elevation 5,280 feet) is thirteen miles west of the area. The Vernal station has complete information of temperature for 29 years, precipitation for 34 years, wind for 7 years, and evaporation for 7 years. At the Jensen station the .records of temperature are complete for 17 years and those of precipitation are complete for 22 years (Tables 1, 2, and 3). These re.cords indicate that the climate of the area is character- ized by large fluctuations in temperature and in the amount of precipitation. The area has cold dry winters and hot dry summers. The average annual precipitation for the Monument weather station is 9. 51 inches. This is fairly well distributed over the year, but the winter months receive less than any other season. Greatest precipitation occurs during the spring and early fall months. The summer months receive only a moderate amount of precipitation with July as the dry .month of the season. The distribution of the precipitation of the Vernal and Jensen stations is similar to that of the Monument station, but average precipitation is generally less. The minimum temperatures recorded for the two stations are -38° F. for Vernal and -36 °F. for Jensen. The length of the growing season for Vernal has varied greatly. The average frost-free period extends from May 26 to September 21 (118 days). The longest fros.t- fros.t period was from April 22 to October 19, a total of 180 days (1897). The shortest number of frost-free days was from July 4 to TABLE I. PRECIPITATION IN INCHES {Average monthly

and average annual for Vernal 34 years 1 Jensen 22 years and Dinosaur National Monument 7 yea.rs)

It· J F M A M J J A s 0 N D Av. Ma:x. Min.

Vern~! . 61 . 52 . 75 .• 90 . 83 . 49 .61 .73 I. 02 . 95 . 78 .62 8.82 14.78 4.62 Jensen • 57 .41 • 60 . 86 .74 . 72 .55 .75 . 83 . 96 .49 . 96 8.44 12.55 3.62

Monument .64 .31 75 1.11 .55 , 90 .42 • 95 • 93 1. 54 • 45 . 96 9.51 12.24 7. 41

TABLE Z. TEMPERATURE IN DEGREES FAHRENHEIT (Average monthly and average annual for Vernal 29 years and Jensen 17 years)

J F M A M J J A s 0 N D Av. Ma:x. Min. Vernal 16. 2 22.7 35.0 44.5 54.9 63,.2 69..9 55. 9: ·5s, 9 46. 6, 3.3. s·:20. 0 44.4 103.0 -38 .... N Jensen 13.7 21.5 35.3 48. 0 57.0 63.9 72. 3 69-.6 60.9 48.5 32.9 21. 7 45,4 106.-0 -36

TABLE 3. AVERAGE EVAPORATION IN INCHES AND WIND IN MILES (Vernal 1948-1954)

A M J J A s 0 Evaporation 5.25 7. 10 7.72 7.18 6.25 5.03 3.35

Wind 2279 2109 1367 710 593 622 563 13 to September 4, a total of 62 days (1921). Measurements of evaporation rates and wind movement have been recorded for the g,rowing season at the Vernal station since 1948. April, May, and June are recorded as the months with the greatest amount of wind. During the months of July, August, and September there is less wind. The wind decreases from an average of 2279 miles in April to an average of 563 miles in October. The greatest water loss occurs during May, June, and July when high temperatures coupled with large amounts of wind cause high evaporation.

Field Methods

Collecting areas were established in the Spring of 1955. These areas were chosen by the type of vegetative cover and by the geological formations. Each area was visited and collected several times during the spring and summer of 1955 and some of them again during the ,Spring of 1956.. Plants were collected in various stages of development to assist in identification. A list was made of all plants noted in each area. Many plants not found in the designated collecting areas were collected wherever they occured. All plant specimens collected by the author are in the herbarium at the Brigham Young University. RESULTS

Checklist of Vascular Plants

A checklist of plants of the area was prepared from those collected by the writer and those reported by various bo.tanists during the past fifty years. The specimens collected by the writer were collected mostly during the summer of l955 and during the spring of 1956 and are in the herbarium at the Brigham Young University. The list of species is included in the appendix {page 48). The list contains 360 species and subspecies which represent 59 families. The most common families are the Compositae, with Artemisia tridentata as the most common species, Chenopodiaceae, represented by several species of Atriplex., Graminae, represented by Oryzopsis hymenoides, and Leguminosae, represented by the Genus Astragalus. The families are arranged in phylogenetic order after Har:rington. (1954} with the genera and speci.es listed alphabetically under each. family •. Each species nam.e is followed by a represent• ative collection locality,, altitude, geological formation (where known), and the collectors name and number. With£ew exceptions the names used in this list are after Ha.rrington (1954). The names not listed in Harrington were ta:kea from the various manuals listed in the Ref erences. Vegetative Map

A vegetative map of the Utah portion of the Dinosaur National Monument was constructed from. field observations (Map 1). This work was undertaken to show the 4istribution of the various types of vegetative cover. The topographic and geologieal maps (Maps 2 and 3) are arranged so that vegetation can be correlated with geological formations and topography (see pages 15, 16, and 17). It must be noted that the map is quite general owing to the small scale. Thin geologieal formations having great differences in vegetation £rom the formations on either side may be included in an altogether different plant association. Th.e Monument may b.e divided into eight plant communities. These include the junipe.r-.pinyon community which co~ers more of the area than any other. The pinyon is sparce and relatively un ...

14 VEGETATIVEMAP OF THEUTAH PORTIONOF THE

DINOSAURNATIONAL MONUMENT

LEGENDFOR VEGETATION

E===3JUNIPER·PINYON ITiilllJUNIPER

PONDEROSAPINE SAGElllUSH AND SERVICEBERRY

JUNIPl!RAND lim DOUGLAS FIR SPARCELYVEGETATED t!...•~CLIFFS

GREASEWOOD SAGElllUSH ~COMPLEX

RIVERBOTTOM UNITED STATES DEPARTMEN T OF THE INTERIOR EXPLANATION GEOLOG I CAL SURVEY

IN COOPERATION WITH THE NATIONAL PARK SERVICE ~~CJE3E=JEJ Road. and Poor public or Trail Stateline buiklinp pri....,te ro.d u.~anc1 TOl'OGRAPHIC MAP udNCo'HredCWDen OF THE ..-~:~- DINOSAUR NATIONAL MONUMENT L_.=_J School El____ .. ation abo

Su~-nl941

"o•ycon,,P,"0_1ect•o<' 1927No,..~A,..encancl'l•u.,., 0 1cc5oc°?o~!ttdca~~o~"c~·1~:~~~'R~•~~ ;nd U111n(C.ntrall rect•ngul•rcoord ;n• tesys tems £d·•,ono f l950 .,.. c,~-·.,,oeJo,10,~: __,.,..._._,__ RO,t,OCUSS.IFICAT!OII __,__ -- ·-= -.,,--•·- -:!.;._;..;:::::=.'"' .···"•· Qus.- Os-- LEGEND FOR GEOLOGICAL MAP GEOLOGICMAP OF DINOSAUR NATIONAL MONUMENT AND VICINITY. N. E. UTAH-N . W COLORADO ByG.E . untermonn,.mdB.RUntermonn

PLATE ll OF BULLETIN 42·UTAH GEOLOGICAL AND MINERALOGICAL SURVEY Field work1943·194B l>l•t1toc:•H &R1r:..nto.1111vi,11<11poti1tm C.h"1nl1tormotion llMmorl,1ilhtone,son<1•to- Ft~lt-wor1,oti9in

8row111 p.,~ for,nalio11 "";1~::::.•~~'!:n."•tl

11:mm:l Mcincoa Shct/11 ''"•Y lo Y•llow,~h .sh•'•· •o- ,,..,..,__ oil.

Frontl1r Sond_,fo.,.. Par~ City formotion so,...,,.,.,,,.andc~/. Umu1,.,,,,, ,,..Jc(~,ph<>fic lo _,tJ. C~rt. !1o,in1.

Mowr1 11!<1/1 .Silv,,,y- U11afhcr1r,9 !!!./t1c1ouo shaAI. Wabie,,..,nd,ton

Do"-OfO sondsto~ Co"',lom,.,-olicscmdst~. ,a,,...corbon- oc.e,,us shO"le. ruso~ Jho/e 1,. Lruoto sandstone m1mbcrsin1ow•Yparf. ---- foult;J<>b1cu~H ,(h o,p, st~11Ceofb ed1 18 impol'tant in the plant community over much of the area. The area marked juniper is mainly Ju:hiperus utahensls~ but grades into Douglas fir and the sagebrush=serviceberry associations at the higher eleva= tions. The sagebrush-serviceberry community occupies the Blue Mountain and Yampa plateaus. Ponderosa pine is restric.ted to the top of Split Mountain and to a small patch near ,Doug Chew's cabin on Blue Mountain. The sagebrush community occupies the lower areas along drainages. The aspen community is limited to a small stand near Doug Chew's cabin on Blue Mountain. The greasewood complex occupies much of Rainbow and little Rainbow Parks as well as much of the area south 'Of the headquarters area. The major plant species on the sparcely vegetated cliffs is Juniperus utahensis. The river bottom community has Populus spp. and~ spp. as the major species. Plant Communities of the Geological Formations

Table 4 {p. 23) indicates the occurrence of the major species of each geological formation. The formations are not listed in the order of the following discussion, but are separated into shale, sands tone, or alluvium. Table 4 also shows the position of the selenium indicator plants, Astragalus saurinus and Stanleya pinnata. The plant c-ommunities of each geological formation will be discussed separately and will include a qualitative description, with comments on successional trends and a di'scussion of the more important environmental factors. The sequence of the formations will be the same as that used in the section on geology.

Lodore formation

The author has not collected on the Lodore.

Mississippian undifferentiated

The most common plant is Juniperus utahensis. Pinus edulis is present, but becomes less abundant as the elevation decreases. Amelanc.hier utahensis and Fraxinus anomala are common along the ravines which drain the formation. Grasses and some species of ·cruciferae grow on small flats along the drainages. On steep south= ern slopes all plants are of low density. The dominant species found on this group are the same as those found on the Morgan formation TABLE 4. Shale -sandstone .....(I) 111 4) k (I) A (I) § k (I) s ... (I) (I) A (I) Major species ..... 0 A 0 A ~·'"' A n! A ...A 0 0 ....a i 0 as •.-1 ... e i:I E ,I,,) ., a s 0 k k tg Cll u E ; 'cd RI 1k !J) ;J E : ik Cl) sk 0 n! g u k al !J) .e "' I'll Cll (I) A § Cll llt 0 (I) Ill >-0 1-ri ... Cll IU k •.-1 .... 0 !I ...111 I-;;;' +> k ; Cll r k (I) "" 0 > 'l i.8(I) "" k -as ...... ;• t:a1 c3[%.I J ril I\, 6 at. ~· < Am.elanchier utahensis X xx X X X X X X X X X X X X

Artemisia tridentata X X X X

Atriplex co.nfertifolia X Ix :lC. I, Atriplex-corrµe:ata IX :

Cercocarpus intricatus X .x lX X X

~· Erioa:onum corvmh&swn X

Erio2onum effusum lX -.

Enhedratorrevana X X

Ephedra viridis X lx X X X X x X

Fraxinus anomala X

Juniperus uta.hensis X X X X X X X xx ::xX X .:X X

Pinus edulis X X X pc

Populus spp. X

Sarcobatus vermiculatu.s X X

Tetradvmia spinosa X X

Astraa:alus saurinus X :x X X

Stanleya pinnata X ..:JC X X X 20 discussed below, but the plants are less abundant. Other plants found on this group are :

Artemisia tridentata Hymenoxys acaulis . Cer·cocarpus intricatus Stipa comata Echinocerus sp.'.· Morgan formation

The mos.t conspicuous plant on the Morgan is Juniperus utaherisis~ Pin.its· edulia being of secondary importance. At higher elevations the Pin.us·edulis· is abundant, but it decreases in density at the elevation decreases. On small flat places, along the drainage washes, small patches of grass (Agr.opyron spicatum) form meadows. The above discuss.ions is a description of the vegetation on southern exposures on the north of the Green River in the Split Mountain Gorge. This area is one that has received very little or no grazing by doI?1estic stock and is in a very natural condition. There are signs of irazing by wild animals and certain plants {Ephedra viridis, Amelanohier utahensis and Cercocarpus intricatus) are receiving .rather heavy use. Bromus tectorum is growing in open spaces between s.ome of the plants. Other plants on the formation are:

Asclepias cryptoceras Gilia aggregata ~el~nch,ier utahensis Hymenoxys acaulis Aster arenosus Oenother a caespitosa Castilleja chromosa Penstemon arenicola Cercocarpus intricatus Stipa comata Fra.xinus anomala

. Weber formation

The vegetation on the Weber is highly varied. At the top of Split Mountain is a for·est of Pinus ponderosa that is mixed with~~ dotsuga taxifolia. These grade into the juniper-pinyon forest at lower elevations and in some places all of these trees are found growing in the same area with an understory of Cercocarpus intricatus, Cercocarpus montanus, Ephedra viridis, Amelanchier utahensis, and Fraxinus anomala. The juniper-pinyon forest is best developed on this formation in Horse Trail Canyon where the Pinus ~dulis approximately equals .the Juniperus utahensis in relative density. In the box canyons .on the southern flank of"Splll'Nlountain, Pseu:dotsuga taxifolia and Jiii'~erus scopulorum grow at an -elevation of 5, 1'00 feet. 21

Juniperus scopulorum is also found on the north-facing slope of Split Mountain and in Horse Trail Canyon where it grows as a secondary species in the juniper-pinyon forest. Whe-re the exposure is to the west at a steep angle (30 to 45 .degrees) the pigmy conifer forest is dominated by Juniperus utahensis alone. In this situation the juniper is in a poor state of vigor and has few s~edlings. On these western slopes the understory is quite different than in other places in the formation. It consists of Fendlerella I utahensis, Forsellesia meionandra, Philadelphus microphyllus and an occasional specimen of Atriplex confertifolia. At the base of the slope where the incline is less (5 to 15 degrees) the Juniperus utahensis are in a better state of vigor and have occasional seedlings. Here the understory is primarily of Artemisia tridentata. Where the exposure is. to the east at low elevations such as at the mouth of Split Mountain Gorge (4, 800 feet) many plants grow in the moist protected areas at the base of cliffs. In these places Rhus radicans grows in the same location as Shepherdia argentea, Cereo- carpus intricatus, and Rhus trilobata. The understory consists of Chrysopsis villosa, Apocynum canabinum, Asclepias speci,osa, and· several species of Cruciferae. Where a small seep occurs on the Weber at the Split Mountain Gorge campground some specimens of Betula occidentalis are growing among some Rhus trilobata. Other plants growing on the Weber formation are:

Acer glabrum Ivsia gordonii Agoseris glauca · Koeleria cristata Arabis pulchra Lepidium. m:ontanum ·Arceuthobium campylopodium Linum lewisii Arenaria congesta Lithospermum ruderale Astragalus spatulatus Lom.atium simplex Balsamorhiza sagittata Mertensia oblongifolia Cercocarpus ledifolius Oenothera trichocalyx Descurainia pinnata Penstemon arenicola Draba oligosperma Penstemon cyanocaulis Erigeron divergens Phlox longifolia Eriogonum heraculoides Physaria australis Eriogonum umbellatum Poa secunda Gaillardia aristata Purshia tridentata Gilia aggregata Salix exigua Grindelia squarrosa Sedum stenopetalum Hymenoxys depressa Selaginella mutica

Plate 3- Vi ew east of the Green River south of Split Mountain.

Plate 4- Sp li t Mountain . 23

Senecio fendleri Thelapodium rhomboideum Solidago sparsiflora Trifolium gymnocarpon

Park City formation

The most common plant species on this formation is Juniperus utahensis. Artemisia tridentata occurs as patches between the junipers. The Artemisia tridentata occupies the slopes where the soil is deep while the Juniperus utahensis occurs where the soil has been eroded away and where the drainage pattern has been encised into the bedrock. Where the slope is to the south Juniperus utahensis forms an almost pure stand {see plate 3). On north-facing slopes many woody plants form an understory in the juniper. In this place the understory consists of Amelanchier utahensis, Cercocarpus intricatus, and Fraxinus anomala. Where the exposure is to the west Pinus edulis forms a minor part of the pigmy conifer forest. On this exposure the major woody plant in the understory is Artemisia tridentata. On the deep soil where Artemisia tridentata is the dominant species Agropyron spicatum. and A. smithii are common in the understory. Many other annual and perennial £orbs also grow among the sagebrush. Other plants on the formation are:

Abronia elliptica Hymenoxys acaulis Agoseris glauca Lesquerella subumbellata Aster arenicus Linum lewisii Astragalus pur shii Lithospermum incisum Astragalus thompsonae Lygodesmia grandiflora Calochortus nuttallii Oenothera trichocalyx Cryptantha sp. Oryzopsis hymenoides Delphinium nelsoni Pediocactus simpsoni Ephedra viridis Phlox longifolia Erigeron concinnus Physaria australis Eriogonum ovalifolium Plantago purshii Erysimum asperum Sisymbrium lini!olfom Festuca octoflora Sitanion jubatum Grayia spinosa Sitanion hystrix Haplopappus acaulis Sphaeralcea coccinea Hilaria jamesii Stipa comata Hordeum. jubatum

Moenkopi formation

The primary plant species on the Moenkopi is Juniperus utahensis which is from sparce to abundant. Other woody plants 24 that form an important part of the vegetation are Amelanchier utahensis, Ephedra torreyana, Tetradymia spinosa, Atriplex confertifolia, and Fraxinus anomala. In some places on the Moenkopi the stiff clump-forming Forsellesia meionandra forms a conspicuous part of the understory. It must be noted, however, that on most of the formation the density of the plants is very low. The plants are spaced far apart with large areas of bare ground between. Where the formation is covered by a layer of alluvium from another formation the plant cover is very different (see Plate 3). In these situations Artemisia tridentata occupies the drier regions while along the stream courses are such species as Populus angustifolia, Salix spp .• Rhus trilobata, and Betula occidentalis. The selenium indicator Stanleya pinnata is abundant on this I formation in the vicinity of the Split Mountain Gorge campground. The clump forming Astragalus saurinus is also found on this form- 1 ation. This species is also said to be an indicator of selenium. (see page 43). Other plants. on the formation are:

Acer negundo Euphorbia fendleri Amsonia jonesii Euphorbia robusta Androstephiu.m. breviflorum Galium coloradoense Arabis f endleri Gutierrezia ·sarothae Arenaria uintahensis Hedysarum boreale Artemisia spinescens Hilaria jamesii Astragalus chamaeleuce Hymenopappuslugens Atriplex canescens Lappula redowski Castilleja chromo sa Lithospermum incisum Cirsium sp. Mentzelia humulis Cryptantha breviflora Oenothera caespitosa Cryptantha sp. Opuntia sp. Cymopterus purpureus Phlox hoodii Erigeron concinnus Psoralea megalantha Eriogonum corymbosu.m. . Sarcobatus vermiculatus Eriogonum ovalifolium Solidago petradoria Eriogonum spathulatum

Shinarump conglomerate

On the upper surface of the Shinarump, Juniperus utah.ensis and Amelanchier utahensis grow on the crevasses. Another important plant in the crevasses is Forsellesia meionandra. In a crevasse on a north-facing ledge of the formation n.ear the Split Mountain Gorge campground~ radicans is growing out of a mat of 25

Selaginella mutica. .Am.ong the boulders on the lower side of the formation are Artemisia tridentata, Fraxinus anomala, Ephedra viridis, and Leptodac:trlon punsens .. Other plants on the formation are: Astragalus diversifolius Galium coloradoense Arenaria uintahensis Pinus edulis

Chinle formation

The dominant plant species occuring on the Chinle is Juniperus utahensis. The understory is of stunted Artemisia tridentata and .Atriplex confertifolia with an occasional specimen of A:rnelanchier utahensis. In early spring, Phlox hoodii grows in profusion on the north-facing slopes. Grasses are very sparce, but occasionally there is a clump of the tall Stipa comata and some scattered Bromus tectorwn growing among the woody shrubs. Stanleya pinnata occurs on this formation~ but not as commonly as on the Moenkopi formation. J Astragalus saurinus has not been found on the .formation. Other plants on the formation are:

Am.sonia jonesii Chrysothamnus sp. Artemisia spinescens Forsellesia meionandra Astragalus spatulatus Gutierrezia sarcithae Calochortus nuttallii Hedysarwn boreale

Navajo sandstone

The plants occuring on this formation are as varied as the situations presented by the formation. The exposed ridges are character- ized by_ sparce Juniperus utahensis intermixed with Cercocarpus intricatus, C. montanus, .Am.elanchier utahensis, and an occasional specimen of edulis. These plants grow in the areas where sand has accumulated to a sufficient depth to allow growth of plants. In the vertical walled canyons the plants are quite different. Here, nesundo grows along the drainage while Artemisia tridentata and various grasses are found on the small flati,;. At the base of a cliff that forms the east wall of the box canyon in Orchard Creek Draw is a stand of Berberis repens growing on an accumulation of material that has fallen from the cliff. Where a seep occurs the vegetation changes abruptly from a xerophytic to a hydrophytic plant community. Tn>J:?.alatifolia and Juncus sp. occupy the areas of greatest moisture 26 while on the perifery are Smilacina stellata, Solid.ago sp. , Phragmites communis and ElPeus sp. • Other plants on the formation are:

Amsonia jonesii Ephedra viridis Androstephium breviflorum Eriogonum ovalifolium Antenna'ria dimorpha Fraxinus anomala Arabis pu.lchra Gilia aggregata Arabis selbyi Lesquerella Ludoviciana Astragalus diver sifolius Phlox. hoodii Ca s.tilleja chromosa .Psoralea megalantha Cryptantha flava Stephanomeria tenuifolia Cymopterus purpureus Zygadenus paniculatus

Carmel formation

The dominant species of plant occuring on the Carmel is Juniper .. utahensis. The understory consists of Amelanchier utahensis and Efb:edra viridis. The most important herbaceous plant is the tall clump-forming Astra;alus saurinus. The density of all plants on this J formation is very low. Stanleya pinnata is present on the Carmel. Other plants on the formation are:

Cryptantha brevlilora Eriogonum microthecum Eph.edra torreyana Oryzopsis hymenoides Ephedra viridis Tetradymia spinosa

Entrada sandstone

The principal vegetation growing on this formation consists of Ju.niperus utahensist Amelanchier utahensis) and Eeedra viridis. The density of the plants is low with the plants spaced far apart. The large clump forming Lupinus argenteus forms a conspicuous part of the vegetation on the sm.all sandy flats between the strike ridges. Astragalus chloodes is comm.on along the sandstone outcrops of the formation. Other plants on this formation are:

Castilleja chromosa Oryzopsis hymenoides Cryptantha brevlilora Poa longiligula Eriogonum. micro.thecum Poa secunda Lithospermum. incisum

Curtis formation

The author originally considered the Curtis wi.th the Entrada formation because of the similarity of plant cover~ but the presence 27 of Astragalus saurinus on the Curtis denotes the distinct vegetation of this formation" Astras;alus saurinus does not occur on the Entrada formation. The conspicu.ous vegetation consists of Juniperus utahensis~ Amelanchier utahensis-, and Ephedra torreyana. The plants in most situations are very spa.rce. The best development of the plant com• munity is on the east-facing slopes where many species are fou.nd. In these places Oryz?Psis hym.enoides and Hilaria jam.esii occur in scattered clumps. At the base of the slopes and along the washes is an as.sociation of Artemisia tridentata, Tetradymia s:pinosa, and Grax:ia spinosa. Other plants on this formation are:

Asclepias cryptoceras Guiterrezia sarothae Arabia pulch.ra Lupin.us argenteus Artemisia spine se~ns Lupinus pusillus Aster xylorrhiza / Oenothera caespitosa Astragalus chloodes f Phacelia crenulata Astra gal.us pur shii i/ Phlox hoodii Castilleja cb.r0,mosa Poa longiligula Cym.opterus ducaesnense Poa secu.nda ~ryptantha .fl.ava Sisym.brium lini£olium. E:phedra viridis Solidago petradoria Erigeron pumilus Wyethia scabra Eupho.rbia rohusta

Morrison formation

Where the clay parts of the formation stand at a steep angle (30 degrees or more) there are no plants (Plates 5 and 6). The one plant species ob$erved growing directly on the clay was Sareoba.tus vermiculatus. This plant is commonly found along narrow sandstone lenses in the .formation.. Where larger outcrops of sandstone occur many plants are found. The plants grow on the upper surface of these sandstone lenses where the over-burden has been removed by erosion and on the gravel covered slopes and ridges that have resulted from the weathering of the sandstone.

Where the exposure is to the east and south on the sandstone l~nses or gravel covered slopes the dominant species is Atri:plex conf erti!olia. Tetrad1!11:ia spinosa and EE1!:edra torreyana also grow cm the gravel covered areas but occu.r mosUy on the ridges.. Other plants in theae areas are the grasses Brom.us tectorum. and Oryz'2})sis hY?:11:enoides.

Plate 5- Morrison formation.

Plate 6- Morrison formation capped by "blow sand". 29

Wkere the exposure of tk:e sandstone leues and grayel covered alupes ia to tlte na;nh. the damina.n.t plant species: a.re Artemi~da !!:!- delltata and ~n spicatwn. Alwrg th.-e-washes a,t the base of the cla.y slopes many plants a.re fmmd,. Tke most eQJl&picu.o.us plant ia Sa.rcnbatus; v.ermiculatu with tke t-11 cl.ump-~ Aatraa;alus $8.Urln.wJ as the :most important :secondary sp6cies.. Where the soil along tke -wasae-sis a mix.tu.re of •il from other f:ormations .Artem.i~lia. tridentata and Am.elan.duer ~nsis oe¢l1r. Stalit!f! pinna.ta doe• oe,e:ur oa 'the·£onnation but is J :net .al,undant .•

Otlt.er plants l)n the formation are: Allium textile K.och!aa.mericana. Atl:iplex cor~ugata _Sisym.ariu.m lin.ifollum Castilleja di:rot:CJ$4 Sphaeralcea co:ccln.ea Dakota sand.atone

Th:e plants g~ on th.e Dakota are sim.ila.r t_, tkose on th:e Frailer ~tone listed 'below. Jun.il;!n.J u.tall.ensi, and .Junelanchier utah.ensis J:u.rm. tb.e mv:st ccmspiewm:s part of the vegetation. l;n. 'Sm:ne places Artemim .~i~ntata forms an impu:tant part e£ the vegetation. Wla..erethe eap,-rock is exposed to south the vegetation grows am.m:i:_g t1te aoulders whic:JL the surface. :P-. longili~ is in these rocky· ~. Wkere th.e 1J&n.d.y.ha.sal port.ton of .iae fcJrma.ticm. is to tae J10rth Atri}!!ex e-onf,e:r:Ufolia and hood ii form a scattered cover .. Other plants tm th.e Dakota are:

Aselepia:s cryptoce:ras Gi-ayia spinoaa A.g:r~oa spies.tum. Gutierre~ia sa.rothae Artemisia luda'Vieia.na Hila.1."ia jam.es-ii Ast:ra.galu.s cltlcrode s Lappula texana A.triplex eorruga.ta Opu.ntia .sp. Bnmtu$ tecto.rum. Oryzops:is hymenoides Castilleja eknan.0$2. Solidago: petr~ria ~17P.tantha £lava $phaeralcea eoceinea Ephedra viridis Str epta:ntla ella longirostJ"l& Eriog.onmn mierot.h.ecum. Tetradym,ia spinoaa Eriogonum oval.ifoliwn Mo'!!Y $ha.le The most censpi-cu.ous .and the most munerous plan.ts grO'Wing on tlt:e Mowry ;$kale &l"e t_, species o£ perennial E:r.-iojon.u.m ~. Mowry shale

Atriplex nuttallii

sandstone shale 30

Plate 7 - Eri ogonum corymbosum Benth. on the Mowry shale formation.

Plate 8- Frontie r sandstone, Mowry shale, and Dakota sandstone formations. Frontier sandstone

---- Mowry shale

Artemisia tridentata

Alluvium

Sarcobatus vermiculatus 31

Plate 9- Outcrop of Mowry shale in draw west of Rainbow Park.

Plate 10- Horizontal outcrop of Mowry shale capped by Bishop conglomerate. 32 corymbosum, a small local race differing from that found on the .Moen- kopi in growth habit a·nd pubescence, and effusum). It would appear that these species are restricted to this formation in the Monument f Plate 7) but are found widely distributed in other parts of the Rockies. They have not be.en found on any other formations in the Monument except for occasional plants along the contacts of the Mowry with the Frontier and Dakota formations. Where the formation is covered with alluvium these plants do not grow and only reappear where the formation out crops (Plates 8, 9, and 10). The next most prevalent plant is Amelanchier utahensis which follows the strike of the Mowry and does not grow where the formation is covered with alluvium. However, this species does occur in many other formations in the area. In some places scattered plants of Artemisia tridentata and Juniperus utahensis are present. On one part of the formation the basal portion is occupied by robust clumps of Atriplex nuttallii. Where seeps arise Thermopsis montana is abundant. Other species on this formation are:

Aristida longiseta Hilaria jamesii Artemisia spin.escens Stipa comata Grayia spinosa Tetradymia spinosa Gutierrezia sarothae

Frontier sandstone

Where the exposure of the caprock is to the south the plant density is low. Most of the plants grow in the crevasses where there is an accumulation of soil. The species growing in this situation are Amelanchier utah.exuµ.a and an occasional specimen of Juniperus utahensis. At the base of the slope is a talus like accumulation df large rock fragments with a matrix of sandy soil. The main species occurring in this place are Amelanchier utahensis, Artemisia tridentata, and Artemisia spinescens. The understory consists of several species of Cruciferae and Boraginaceae. Where the exposure of the caprock is to the north the density of Amelanchier utahensis · and Juniperus utahensis is greater. The northern exposure 0£ the sandy basal layer of the Frontier has Atriplex conf ertifolia as the main component of vegetation. These plants grow in more or less vertical rows along small drainages down the. slope. Secondary 33

. species occuring in these places are Artemisia spinescens, Hilaria jamesii, and scattered Artemisia tridentata. In other places Agropyron spic:atum and Artemisia trideritata, form the dominant cover. Whe:re the exposure of the basal portion is to the south the most conspicuous plants are widely spaced plants of Atriplex confertifolia growing in definite horizontal rows on the various strata of the formation. Where the exposure of this portion is to the east the numbers and size of the Atriplex c:onfertifolia are greater. At the base of the slopes as the ground levels out Hilaria jamesii forms a relatively dense mat. Other species on the formation are: Abronia eliptica Lappula redowski Arabis pulchra Leptodactylon pungens Atriplex confertifolia l.,.ithospermum incisum Atriplex nuttallii Opuntia sp. Castilleja chromosa Phlox hoodii Comandra umbellata Physaria australis . Cryptantha flava Steptanthella longirostris Glycyrrhiza lepidota Sisymbrium elegans Grayia spinosa Townsendia incana Mancos shale The plants occurring on this formation are mostly those of the "mat-atriple,c association" (Graham, 1937, p. 66). This association, which has Atriple,c corrugata as the dominant plant, is best developed on northern and eastern exposures (Plate 11 ). On steep southern exposures the slopes are practically bare of perennial plants. In small ravines and at the base of the slopes on the southern exposure are several herbaceous annuals Eriogonum inflatum, .~ salsuginosum, E. gordonii, Atriplex saccaria, and Helianthus sp.. A few perennial plants found on the south facing slopes are Atriplex corrugata, A. confertifoli 4, A. nuttallii, Cymopterus bulbosa, and Enceliopsis nutans. This is the only formation in the Monument having extensive areas of the mat-atriplex association, although scattered plants of Atriplex corrugata were noted g,rowing on the Morrison formation c.onditions of soil, drainage, and exposure are similar to those of the Mancos shale. All plants on this formation must be able to tolerate the high salt content of the soil. Leaching of the s,oil proceeds very slowly dueto poor drainage and little precipitation (Untermann, 1954, p. 64). Sarcobatus complex

Alluvium

Frontier sandstone

Atriplex corrugata

Mancos shale 34

Plate 11- Mouth of Orchard Creek Draw near Monument Headquarters.

Plate 12- Mancos shale formation with Atriplex corrugata Wats. 35

Other species on this formation are:

Al.Hum textile Eriastrum di££usum Androstephium breviflorum Oenothera scapoidea Artemisia tridentata Oryzopsis hymenoides Chaenactis stevioides Phacelia dimissa Cb.rysothamnus sp. Sareobatus vermiculatus Cleome lutea Sphaeralcea coccinea

Bishop conglomerate

North of Rainbow Park the Bishop overlays the Morrison formation~ The area consists of rolling hills that £all away abruptly where they are incised by drainages. On these gravel covered hills the dom.- inant species is Artemisia tridentata. The understory consists of grasses and perennial £orbs. Where the Bishop thins as a result of erosion Juniperus utahensis is the dominant plant species. The understory of the juniper association consists of Artemisia tridentata, ..Amelanchier uta.hensis> and Ephedra viridis. Other plants on the formation are:

Agropyron spicatum Elymus sp. Androstephium breviflorum Hilaria jame sii Arabia sp. Sisymbrium elegans * Artemisia spinescens Stipa comata Atriplex con£ ertifolla Viola nuttallii Castilleja chromosa Zygadenus paniculatus Alluvium

There are great differences in the plant composition on the different alluvial soils. The clay soils support plants having the ability to withstand salinity. A relatively flat valley bottom occurs in a wash which leads from Mc Kee Spring into Rainbow Park. In this area Sarcobatus vermiculatus forms an almost pure stand. The understory consists of Suaeda torr~ana and Brom.us tectorum. In this area a large percent of the soil was derived from the Mancos shale and is a gray clay. This same soil type is found on the alluvial fans to the south of the head.quarters area.. South of the headquarters, however, Sarcobatus vermiculatus is found growing in asso.ciation with TetraclJ!:nia spinosa, Atriplex confertifolia, Grayia spinosa, and Chxysothamnus spp.(Plate 11). The position of Chqsotha.mnus is highly variable, but it usually occupies slightly elevated places and the bank$ of washes in the Monument. 36

The higher ground to th.e north of Rainbow Park is occupied by Artemisia tridentata which grades with Sarcobatus vermiculatus in th.e clay alluvium .of the Park • .Along the outwash plain are clump.s o! PopulU$ fremontii and~ negundo .. sp. and Tamar ix gallica occupy th.e bank along the edge of th.e river (Plate 13), Artemisia tridentata is also found along the river bank where it reach.es a height of six feet or more. In one of th.e poplar groves, which has been badly overgrazed, many additional species occur. Among them are Symphor- icarpos occidentalls, 9!uxsothamnus nauseosus., and many grasses (.yro,rron smith.ii, ElEI?:us cinereus, pratensis, and Distichlis sbicta). In the spring of 1955 large mounds of Salsola kali were noted at the north end of Little Rainbow Park and som.e----- of the washes were filled with. it. On the £lats to the north. of the Green River in Island Park are some c:ultivated fields of Medicago sativa. Single specim.ens o£ this plant were noted at many points .along the Green River where it has eacaped. £rmn cultivation. Around the perimeter of the cultivated land i in Island Park the dominant plant ls Artemisia. tridentata. Populus spp. grow along the Green River and along the small stream. channel th.at drains into Island Park from the north. In places where sand has accumulated from the weathering of the Navajo sandstone and adjoining sand producing formations, A.J:temisia tridentata is the dominant plant, with Atri;elex canescens being the most important secondary species. Occasionally specimens o£ Sar.cobatus v-ermkulatus are found along the washes. The native grasses in these areas have been replaced by Bromus tectorum and Salsola kali.. The most important native grasses in these areas are StiP!; comata,- Festuca oetoflora, and Hilaria jamesiL At the juncture of the Entrada and Curtis formations in Orchard Creek Draw a spring arises. Growing on the moist sandy alluvium in this place is a hydrophytic plant community. The moist area near the stream is occupied hy Equisetum kan.sanum. and latifolia. The periphery of this area is occupied by Phrae:ites communis and Sm.ilacin.a. stellata. Around this area on the west. facing-slope are several clumps of Salix caudata. On the east.-facing slope is a small 37 grove of Betula occide.ntalis and ne11:11:do. The size of this hydro ... phytic community has decreased from a much larger area during the recent past. Stumps and pieces of branches of Betula extend far back from where they are now growing. The reason for the reduction of the size of this community appears to have been the formation of a gully that is 30 to 40 feet wide and 15 to 18 feet deep. This gully div- ides the present community into two parts which gradually creep down slope into the gully. In the southwest corner of the Monument ares and dunes derived from the erosion of the Navajo formation. The dunes now cover many of the fermations south o£ the Navajo (Plate 6). For the m.ost part these dunes are stabilized but som.e sm.all sections are in motion. The major woody plants on these dunes are Atriplex canescens and ~sotb.amnus vicidiflorus. Many perennial herbaceous plants are pc.resent, chief among them are: srrobolus C?:7Ptandrus, Psoralea sp. and Oryzopsis hym.enoides. On the more stable part of the dunes a large proportion of the woody plants are Artemisia dracuncu.lu.s. The vegetation on th.e Blue Mountain Plateau is correlated to a great extent with the soil. The soil is mostly a da.rk sandy loam. In some places it grades into a gravel and in other places bedrock outcrops to form ledges. Where th.e soil is thin Juniperus utahensis is the principal vegetation. On the southern exposures 0£ some of the rocky outcrops Cercocaryus ledifolius is present. On the high gravel i-idges are patc:::hes of grass .m.ixed -with numerous clumps of Solid.a.go petradoria. The main grasses a.re Agronron spicatum and Stipa coma.ta. The north slope of Blue Mountain £alls abruptly to the Green River more than two thousand feet below. At the top o£ this slope is an association of Pseudotsuga taxifolia .. Junieerus sc?P,ulor ... um, Pinus ~. and Junipe.l'us utahensis{Plate 2). On the deep sandy soil the dominant species ls Artem.il;iia tridentata.

At Doug Chewls cabin is a grove of P!f:Ulus tremuloides. The understory consists o£ Juniperus scopulorum., .Amelanchier utahensis, Pru.nus virginiana var. melanocarpa, woodsii, and Sym.phori ... earpos sp.. To the east of Doug Chew•s cabin are some Pinus pnderosa growing on very shallow soil. Many oi these trees are growing directly on the exposed bedrock (Webe.r sandstone). On the 38 north-facing slope to the south of the cabin Amelanchier utahensis is the most conspicuous vegetation, but it is exceeded in numbers by Artemisia tridentata. It must be noted that the alluvial areas of the Monument receive very heavy grazing by domestic stock and the relative importance of the most palatable plants is less than in protected areas. Most of the lower part of the Monument is grazed during the spring and summer months by cattle and in part by sheep. The spring grazing removes the plants at the most vulnerable time and many of the more desirable species have been killed and the area taken over by weedy £orbs. Split M.ountain

.-...., Alluvium :4nuviun Green River 39

Plate 13- Rainbow Park.

Plate 14- Astragalus saurinus Barneby on the Morrison formation. DISCUSSION

The distribution of the vegetation in Dinosaur National Monum.ent, as elsewhere. is effected by two primary controls. These controls are the factors of climate and soil. Where the moisture supply is greatest, such as on the Blue Mountain Plateau and on the north-facing slopes, the edaphic factors are largely over-shadowed by the factors of climate. The vegetation of the lower part of the Monument near the Headquarters shows the effects of the greatest control by the edaphic factors.

Shale Formations

Definite correlation between the distribution of certain plant species and associations ap.d geological formations are indicated by this study, especially on those formations made primarily of shale. This agrees with what Graham (1937, p. 32) noted for the Uinta Basin. 11It would seem that wherever geological formations are composed soley of a certain type of rock, such as sandstone, shale, cla.y, etc., then the soil derived from such a formation may definitely affect its plant cover, and there m.ay be a resultant correlation between geological form.ation and vegetation. 11 Each of the three shale formations: the Mancos, the Mowry, and The Morrison, have a distinct flora (Plates 5 to 12). The plants on these formations are not only distinct from those on the sandstone formations but they are distinct from each other. It must also be noted that generally the plant associations found on alluvium are also different from either the shale or sandstone formations {Plates 9 and 10).

40 41

--, In two of these formations, the Morrison and the Mancos, there i are high amounts of soluble salts ~resent in the soil and also toxic amounts of selenium. It is possible that the peculiar floras 0£ these formations can be attributed to these soil factors. The Mowry shale " is not kn.own to contain excessive alkaline salts nor selenium, but is y:e.ry high in silica (Rubey, 1929, p. 127). The residual soil on the Mancos shale formation is a gray to yellow, heavy, alkaline day. The dominant plant species on this formation is the low mat-forming Atriplex corrugata (Plate 12). On north- and east-facing slopes this plant forms almost pure stands. This is the mat-at:riplexassociation described by Graham (1937, p. 66) as being found 11Wh.ere the soil is impervious and white alkali often lies at the surface .. 11 The Mowry shale formation has as its dominant plants two species of woody Eriogonum. Along the Island Park-Vernal road Eriogonum effusum is the dominant species (Plate 9), while along the southern side of the Monument a small local race of Eriosonum corymbosum (Plate 7) is the dom.inant species. .In-the Monum.ent these two species appear to be restricted to the Mowry.. Both -o£thes.e species o£ Eriogonum. (perhaps d.if£.erent races) are found throughout large areas of the Ro-cky Mountains. Closely related sp.ecles of Eri5onu.m 0,ccur on other form.ations in tlte area but do not occur on t1te Mowry. In his discus.sion of tlte Mowry, U~e·rmann (I-954, p. 61) says-, '!It was wortlty to. note that in a majority of places where the Mo-wry shale :outcl"ops .• seattered fellow (Pondero.sa) acid ....so.U loving pine follows th.e strike of the silkious formation, even at the low.est elevations. 11 This phenomenon was not found to occur in the Utah portion of the Monument, but does occur in the Colorado portion and north of Vernal along the Manila road. The flora of the Morrison form.ation may be divided into two groups: those species growing on the clay portions and those species growing on th.e sandstone lenses. If any plant on the clay part can be descl"ibed as d-0m.inant it is Sarcobatus vermiculatus. In many places this is the only plant on the clay portion (Plate 5). In their discussion of the Morrison formation, Knight and Beath (1937, p. 17) said, "The Morrison is known to contain selenium throughout its en.tire thickness 42 in the localities in which it has been studied.•·• Later Beath (l943, p. 698) noted that p,r.actically all native vegetation on the Salt Wash m:ember of the Morrison is toxic because of selenium content. The selenium indicators Stanleza pinnata and Astragalus saurinu.s occur on th.is formation. The primary vegetation on the sandstone lenses is .A.triplex con£ertifolia. Sandstone Formatlons

The sandstone formations include all those formations which upon weathering break down into sand or gravel. They are the Mississippian,

Morgan 1 WeberJ Park City, Moenkopi,. Shinarump, Chinle, Navajo,

Carmel, Entrada 1 Curtis, Dakota, Frontier, and Bishop formations. On all of tlle formations, but the Bishop and sections of the Park City, the dominant species is Juniperus utah.ensis with the understory gener ... ally consisting of Axnelanchier utahensis, Cercocaraus intricatus., Fra.xinus anomala, Pi.nus edulis, and Artemiaia tridentata. At the elevations of 6,080 and above the number of Pin.u.s edulis approximately eq:,uals the number o£ Juniperus utahensis. Below----- 6, Q.QOfeet the numlter of J?inus: edulis. are smaller until at 5._.01.fl feet there is only an occasional sp,ecimen. This suggests t:b.at juniper is able to survive under the more xer.ophytic conditions of the lower elevations. The major difference betw'een the vegetation on the sandstone formations ia the density and relativ-e abundance of th.e varmu.s species (]?late 3). Where the soil on the Park City formation is relatively thick there ls.a. mixture of Artemlsia tridentata and various grasses.. Where the soil is thin or rock outcrops the dominant species is Juniperus utahensis. This same general picture applies to the Bishop conglomerate.. Where the formation is relatively thick and not cut by stream. courses the dominant species is Artemisia t:ridentata, but where the formation is thin or has been e:rnded away the dominant species is Juniperus. utakensis. The plants which are dominant on the shale form• ations are pre,aent only as nccasional speeim.ens on the sandstone formations. Alluvium

On the alluvium that has been largely derived from the erosion of the Weber and Navajo $B.ndstone formations the principal form of 43 vegetation is Artemisia tridentata (Plate 3) • Where th.e major source of the parent material has been the Morrison or Man.cos shale formations the vegetation consists largely of Sareobatus vermieulatus (Plates: t), 10, 11). Selenium

There are certain species that are restricted to formations known to contain selenium. Selenium. has been shown to be toxic to some plants but others tolerate it and still others may possibly require it (Trelease,. 1938). There are at lea.st five fo.rmations in the Monu- ment that support selenium indicator plants. They are the Moenkopi, CJtlnle.Y Carmel., Curtis. and Morrison £.o.rmations. The Park City. Shina.rump, Dakota,. and Mancos formations may also prove to be aeleniferous (Beath;, 1943). Several selenium indicator plants have heen collected. The tall clump ...forming 4Btragalus s,a.urinus ( !:• raph.l!l.elensis) reported by Beath. et. al. (PJ41. p. 889) a:s ."a selenium dependent species. 11 This species of Astragalus occur·s commonly on the Moenkopi, Car.me!, Curtis and Morrisony but ha.s not 'been noted on tlte Chinle nor on any of the possible bearers of selenium.

1 Prince•splum.e(Stanl~I! pinnata) also • ••• requires consider- able selenium" (Cannon, 1952., p. 765). This plant is common on the same.formations as Astra,;alus saurinus .• but also occurs on the Chinle formation.. Other s.elenium indicator plants collected in the Mmmment include: Astzagalus th.Qmpaona.e, collected from rml:y one locality on the Park City formation, Aatra5alus. bisulcatus~ collected from. one locality on alluvium in Rainbow Park, and Astra,;alus confertiflo,ru:s:;. collected from the Morrison formation 'Where it is lol:ally abundant. Vegetation Zones

Three general vegetation zones occur in the Monum.ent. They are the low-altitude mixed desert shrub sone, juniper-pinyon zone, and the mid-altitude sub-montane shrub zone. The mixed desert shrub zone is composed of several plant ass0ciations beginning with the Sa.rcobatus-Tetradymia association in the southwest corner of the Monument.. This zo.ne also includes the mat ...atriplex association 44

on the Mancos shale formation, the Eriogonum association on the Mowry shale formation, and the low-altitude Artemisia association on alluvium up to 5, 800 feet in elevation. The juniper•pinyon zone is a complex which ranges from almost pure stands of juniper to mixtures of many species. This zone is best developed at elevations near- 6, 000- feet where the juniper and pinyon are nearly equal in numbers. This z:oneciB not--eonnr1e•Pie,ge.~¥

Disturbance

The composition of the plant communities existing in the Monu- ment at the present time may differ greatly from that of the original 45 vegetation. Grazing has had a profound effect on the quantity and c.omposition of the flora. On this subject, Graham (1937, p. 60) said, "It is unfortunate that our botanical exploration of the Uinta Basin was not pe>ssible fifty years soon, for then the vegetation would have been in an undistrubed condition. Within the last half-century the plant cover must have changed greatly, due largely to overgrazing. This certainly affected the cover pattern in respect to numbers of individual plants, if not the floristic make-up of the vegetation, from which some species may have been exterminated." Stoddard fl 938) noted that Russian thistle was abundant in the salt-shrub z.one and that the original bunch grasses and other palatable plants 11 .... hav.e been reduced to me:re trac.es. 11 Much of the Monument is badly overgrazed and the more desirable grasses and forbs have been greatly reduced. In their place are such plants as Salsola kali and Bromus tectorum. According to Harrington. (1954, p. 269) Halogeton glomeratus (Bieb.) Mey. has been reported in eastern Utah. As yet this species has not been found in the Monument. As might be supposed much of the area has been subjected to accelerated sheet and gully erosion. Terracing is common in the Island Park-Rainbow Park region and huge gullies may be seen in practically every draw. The stream in Orchard Creek Draw is carrying .a heavy load of sediment. Through part of its c.ourse this strea1:9 travels through a gully of recent origin that is from 15 to 18 feet deep and 30 to 40 feet wide. It is possible to follow an old wagon road up Orchard Creek to a point where it is incised with a gully sev- e:ral feet deep and too wide to jump across. SUMMARY

The results of this study indicate that definite correlations do exist between the vegetative cover and the geological formations in the Dinosaur National Monument. The formations having the greatest differences in vegetation are the shale formations (Mancos, Mowry, and Morrison). On each of these formations the plant association is distinct. The dominant species on the Mancos Shale is Atriplex corrugata. Eriogonum corymbosum and .E. effusum are restricted to the Mowry shale formation in the Monument and on this formation these two spe.cies are the dominants. The most typical plants on the Morrison formation are Sarcobatus vermiculatus and Atriplex confer• tifolia. Artemisia tridentata and Agropyron spicatum occupy some' of the sandstont lenses of the Morrison formation. The sandstone formations (Mississippian, Morgan, Weber, Park · City, Moenk.opi, Shinarump, Chinle, Navajo, Carmel, Entrada, Curtis, . Dakota, Frontier, and Bishop) have plant associations which are similar. The dominant species on most of these formations if Juniperus utahensi.s. Artemisia tridentata is the dominant species on sections of the Park City formation, Bishop congh>merate, and on sandy alluvium. The understory of the juniper may c:onsist of all or part of the following species: Amelanchier utahensis, Ephedra viridis, E. torreyana, Ceiyocarpus intricatus, Pinus edulis, Artemisia trid-:- entata, and Fraxinus anomala. Many of the minor species occur on aLl ~£ the sand producing formations. The greatest differences between the sand producing formations are the density and .relative abundance of the plants growing on them. The dominant species on alluvium are Artemisia tridentata and Sarc,obatus vermiculatus. These occur mainly on alluvial fans and flats in some small valleys. Along the Green River and smaller s.tream courses the vegetation consists of Populus-Salix associations. The selenium indicator plants, Stanleya pinnata and Astragalus saurinus, occur on five formations: The Moenkopi, Chinle, Carmel, Curtis and Morrison formations known to contain selenium.

46 47

The most important factors in the distribution of plants in the area are the availability of water and edaphic factors. Hydrophytic plant c.ommunities are typically found along streams and seeps which are not sufficiently saline to be toxic. The effects of elevation, slope, and exposure are only incidental to their primary effect upon the amount of water available to the vegetation. The more mesophytic species (~ ponderosa, P. edulis, Juniperus scopulorum, and Pseudotsuga taxi:folia) occur at the higher elevations and on the north facing slopes. The effect of wind is primarily the removal of water, especially, on the windward western and s.outhern exposures where plants are of lowest density. In this arid region where the amount of rainfall is not sufficient to leach the salts from the surface of the ground there is a vast accumulation of these salts. Even greater accumulation of salts occur where drainage is poor, such as on the Merris.on and Mancos shale formations. APPENDIX

List of Vascular Plants with Ecological Annotation

EQUISETACEAE

Egu.isetum kansanum Schaffn.

On sand in a moist seep along Orchard Creek, alluvium, 4, 900 ft. alt •.• Welsh 194.

SELAGINELLACEAE

Selaginella mutica D. C. Eaton

In a crevice on the north ...facing side of a cliff, Horse Trail Canyon, Weber formation, 6,000 ft. alt .• Welsh 362.

PINACEAE

Juniperus scopulorum SarB.

Rocky north-facing slope in Horse Trail Canyon, Weber formation, 6,000 ft. alt., Welsh 249.

Juniperus utahensis (Engelm.) Lemmon

Sandy well•drained ridge, Beaches Draw, Weber formation, 5,050 ft. alt., Welsh 60.

Pinus Engelm.

Rocky north-facing slope in Horse Trail Canyon, Weber formation, 6,000 ft. alt., Welsh 2.43a.

Pinus ponderosa Dougl.

Rocky flat at summit of Horse Trail Canyon, Weber .formation, 6,000 ft. alt .• Welsh 246.

Pseudotsuga ta.xifolia (Poir.) Britt.

Rocky stream bank in a box canyon, Beaches Draw, Weber .formation, 5,050 ft. alt., Welsh 56.

GNETACEAE

Eeedra torreyana Wats. Dry sandy ridge near Split Mountain Gorge Campground, Moen- kopi, formation. 5,050 ft. alt •• Welsh 382.

48 49

Ephedra viridis Coville

Rocky slope near the Island Park-Vernal road, Curtis formation, 5,. 200 ft. alt.,, Welsh 102.

TYPHACEAE

Typha angustifolia L.

Gulch between spring and headquarters, Wolf and Dever 5054.

Typha latifolia L.

Sandy alkaline seep on the Navajo sandstone_, north of Split Mountain., 5, 500 ft. alt., Welsh 341.

SPARGANIACEAE

Sparganium sp.

Small pool along Green River, Split Mountain Gorge, alluvium, 5,000 ft. alt .. , Welsh 395.

NAJADACEAE

Za.nichellia palust.ris L.

Small pool along Green River, Split Mountain Gorge, alluvium, 5,000 ft. alt., Welsh 395.

GR.AMINAE

Agro&ron _pseudorepens Scribn. & Smith

Sandy flats at Split Mountain Gorge, Wolf and Dever 5238.

Agropyron smith.ii Ryd.b •

. Sandy meadow under Populuf fremontii, Rainbow Park, alluvium, 5,, 000 ft. alt. , Welsh. 307.

Agropyron spicatum (Pur sh. ) Scribn. & Sm.ith

Steep north-facing cobblerock slope in the draw west of Rainbow Pa:rk., Bishop conglomerate, 5,200 ft, alt., Welsh 327.

Agropyron trachycaulum (Link) Malte

Ditch bank, B. F. Harrison 7757.

Aristida fendleriana Steud •

. Slopes west of entrance road,, red sandy clay soil1 Wolf and Dever 5032. 50

Aristida longiseta Steud.

South...facing slope in bands of clay between lenses of shale, near the Island Park-Vernal road, Mowry shale, 5,800 ft. alt., Welsh 364.

Beckmania srzigachne. (Steud. ) Feril,ald.

Wet sand bar.,. east side of Green River, Split Mountain Gorge, alluvium, 5,000 ft. alt., Welsh 390.

Brom.us inermis Lerss.

Along .a fence line, near Doug Chew's Cabin, Blue Mountain Plateau, alluvium, 7, 400 ft. alt. , Welsh 505.

Bromus tec.torum L. Sandy soil, near Doug Chew' s cabin, alluvium. 7. 400 ft. alt. , Welsh 475.

Distichlis stricta (Torr.) Rydb .

. Small meadow near alkaline Mc Kee Spring, alluvium.. 5,250 ft. alt. , Welsh 332.

Elrn!us .cinereus. Scribn. & Merr .

. Sandy meadow under Populus fremontii, Rainbow Park, 5,000 ft. alt..., Welsh 321.

Festuca octoflora Walt.

Understory of Artem.isia tridentataJ'. sandy flat., Orchard Creek Draw, alluvium., 4,900 ft. alt •• Welsh 199.

Hilaria jam.esii (Torr.) Benth.

Ste.ep sandy slope on Curtis formation"' Orchard Creek Draw. 4,800 ft. alt. , Welsh 182.

Hordeum juba.tum L.

Wet sandy soil, Rainbow Park, alluvium, 4, 800 ft. alt. , Welsh 166.

Oryzopsis hI?Aenoides (R. & S. ) Ricker

Clay alluvial fan near Orchard Creek Draw, alluvium, 4, 800 ft. alt., Welsh 166. l?hragmites communis Trin.

Sandy alkaline seep along Orchard Creek, alluvium, 4, 800 ft. alt. 1 Welsh 438. 51

longiligula Scribn. &: Will.

Sandy rill, west of Island Park, alluvium, 5,000 ft. alt., Welsh 110.

pratensis L ..

Observed in Rainbow Park, alluvium, 5,000 ft. alt., not collected.

Poa secu.nda Pres!.

Shallow soil, near Doug Ch.ew's Cabin, Weber formation,, 7,400 ft.. alt. , Welsh 482.

Polypogon monspeliensis (L. ) Des£.

Marshy salt £lats, Mc Kee Spring, Wolf and Dever 5254.

Sitanion hystrix {Nutt.) J. G •. Smith

R.oeky north-facing slope, west of Rainbow Park, Bishop conglomerate, 5,000 ft. alt., Welsh lZ4.

Sitanion jubatum J. G. Smith

East-facing gravel covered !ijlope, Split Mountain Gorge, Bishop c:omglomerate, 5,000 ft. alt., Welsh 271.

S;porobolus aeroides (Torr.) Torr.

Sandy flood -plain along Green River, Rainbow Park, alluvium, 5,000 ft. alt., Welsh 323.

Sporobolus c.ryptandrus (Torr.) A. Gray

Wet sand along river bank, Rainbow Park, alluvium, 5,000 ft. alt." Welsh.312.

Sporobolus sp.

Dry sandy bank in river bottom, with Elyrnus cinereus and .2.l:u:·agmites. communis, Split Mountain Gorge, alluvium, 5., 200 ft. alt., Welsh 385 • . Stipa---- comata Trin. &: R.upr. Gravel covered south•facing slope in Split Mountain Gorge, Morgan formation., 5,. 800 ft. alt. , Welsh Z32.

CYPE+tA,CEAE

Eleocha.ris eng;elmanni Steud.

Sand around alkali spring south ef road to Island Park, 5,700 ft. alt •., Welsh 393. 52

Eleocharis macrostachya Britt.

Wet sand along Green River, Split Mountain Gorge,, alluvium, 5,000 ft. alt., Welsh 393 .

. Seirpus acutus Muhl.

Clay, alkaline seep at contact of the Mowry and Dakota formations, Horse Trail Canyon drainage, 5,500 ft. alt., Welsh 348 .

. Scirpus americanus Pers.

Alkaline seep, in gley, Mc Kee Spring, alluvium, 5, 200 ft. alt. , Welsh 331.

Scirpus pallidus (Britt.} Fernald.

Ditch bank, B. F. Harrison 7757.

JUNCACEAE

Juncus balticus Willd.

~lay alkaline seep, base of Mowry formation, near Mc Kee Spring, 5,500 it. alt., Welsh 347.

Juncus bufonius L.

Wet sand around alkaline spring south of road to Island Park, 5,700 ft. alt. , Wolf and Dever 5265.

Juncus torreyi Coville Wet sand bar adjacent to a small pool of water along the Green River, Split Mountain Gorge, alluvium, 5,000 it. alt .. , Welsh 392.

LILIACEAE

Allium acu.minatum Hook.

Part of understory in the aspen grove near Doug Chew 1s cabin, alluvium, 7,200 £t. alt., Welsh 416.

Allium textile Nels. & Macbr. \ ' Secondary species on a flat covered with Artemisia tridentata at the nol."th end o£ Red Wash, alluvium, 5, 750 ft. alt., Welsh 205.

AndrosteP!1:,ium breviflorum S. Wats.

1 Gravel covered hills north of Rainbow Park, Bishop conglomerate.¥ Si,100 ft. alt., Welsh 134. 53

Calpcl\prtus nuttallii Torrey

West-facing slope as a secondary species in A.rtemisia tridentata, Park City formation, S, 800 ft. alt. , Welsh 291.

Smilacina stellata (L. ) Des£.

Sandy alkaline seep along Orchard Creek, alluvium, 4, 800 ft. alt., Welsh 191.

Yucca harrimaniae Trel. One mile east of Headquarters, Curtis and Entrada formations, W. A. Weber 5441. Zzgadenus e,ekulatus (Nutt.) s. Wats .. Shallow sandy soil as a secondary species among Juniperus uta.h.- ensis, Navajo sandstone, 5,050 ft. alt., Welsh 76. -

- ORCHIDACEAE Curallorhiza striata Lindl. ·

Sandy soil under Po~ulus tremuloides stand, near Doug Chew's Cabin, Weber sandstone, , 400 ft. alt. 1 Welsh 4Zl

Epi;pactis gigantea Dougl.

Collec.ted by Graham in Split .Mountain Canyon, 5,000 ft. alt., Graham 7831b.

SALICACEAE

Po;eulus acum,i.na.ta Rydb.

Associated with!· an~stifolia and~- fremontii along the Green River, Split Mountain orge Campground, alluvium., 5,000 ft. alt., Welsh . 384 . Popaj.us angusti.folia James

Along a small intermittent stream, Beaches Draw, alluvium, 5,050 ft. alt., Welsh 189.

Populus frem.ontii S. Wats.

Along stream course in Orchard Creek Draw, alluvium, 4., 900 ft. alt. , Welsh 67.

Po;eulus tremuloide s Michx.

On the slight southern exposti.re in deep .bl.a.cit soil near Doug Chew•s cabin., alluvium, 7, ZOOft. alt., Welsh 415. 54

. Salix hebbia.na..Sa.rg.

Mois.t h.Dllow in. draw behind headqu.arter.s, V/,.A. Weber 5305. Salix caudata (Nutt .. ) Heller Moist sandy .seep, Orchard C,:eek Draw, alluvium, 4,900 ft.. alt •• Welah1 118.

~exie,aNutt. Flood plain along Green River, Split Mountain Gorge Campground, alluvium, 5, 000 ft,. alt. , Welsh 387.

§a.l.btlutea Nutt .•

Sandy soil along stream course, Beaches .Draw, alluvium, 5., 050 It,. alt., Welsh 63. BE:TULACEAE Betula occidentalis Hook.

Grcvring with. 1th.us. triloba.ta on a seep. Split Mountain Gorge Campground,,. Weber san.o.st

C eltis occidentalis L. Sandy soil at th.e base of a cliff (Entrada. sands.tone),, alluvium, 4,880 ft. alt .. , Welsh. 439,.

LORANTHACE.AE A,rceuthobinm camp,:loP2di.llln forma divaricatum (Eng.elm .•) Gill Parasitic on Pin.us edulis in Horse Trail Canyon, Weber form.• atiun.,1: 6::.r000 ft. alt::-Y eli1i: %43. SANT.Al,.A.CEA.E

Comandra umaella.ta (L.) Nutt. Sandy south-facing slope, Orchard Creek Draw, Frontier formation, 4,800 ft .• alt., Welsh 462. POLYQONACEAE

&i-101omun. 'bi.color Jo.ne.s Headquarters area, sandy hills east o£ west draw~ Bradley 5304. 55

Eriogonum. cernum Nutt •

. Split Mountain Campground, 5, 250 ft. alt. • Wolf and Dever 5084.

Eriogonum ·eo,rrn:ibosum Benth~

. Steep east-:facing slope near $:,lit Mauntain Gorge Campground, Moenkopi formation, 5,000 ft. alt .. , Welsh 379. Eriogonum cory;nbosum Benth.. (Small local race)

bominant plant species occuring on the Mowry shale formation, Orchard Creek Draw, 4,900 ft. alt~, Welsh 456. Erio1onum. eifusum Nutt.

Mowry shale outcrop, west o£ Rainbow Pax-k, 5, 250 ft. alt., Welsh. 330a.

Jfi-iog.onum. heraculoides Nutt.

North-facing slope.,, north of l)oug Ch.ew 1s Cabin, Weber forma ... tion, 7. 500 ft. alt., Welsh 509.

Eriogonum inflatum Torr. &: Frem.

South-facing slope on gray clay, southwest monument boundary. Mancos ska.le formation,. 4:, 800 ft. alt. , Welsh 41 l.

Erio1onum 5ordoni Benth.

South-facing slope on gray c4y, southwest monument boundary, Mancos shale fonna.tion, -4.,800 ft. alt. , Welsh 407. Eriogonum microthecum Nutt.

Red sandy soil at the- top 0£ ridge, .west side of Orchard Creek Draw, Carmel formation, 5, 000 ft. alt. , Welsh 442.

Eriogonum. ov:alifolium Nutt.

West...facing slope as a secondary species amo:ag Artemisia tridentata, Park City formation, 5 .. 8~0 ft. alt .• Welsh 287. -

Eriogonum salsuginosum {Nutt. ) Hook.

South-facing slope on gray clay, southwest mo-num.ent boundary, Mancos shale formation, 4,800 ft. alt. , Welsh 410.

Eriogonum spa:thulatum Gray Small sandy ridge near Split Mountain Gorge, Moenkopi formation, 5,000 ft. alt.,, Welsh 377. 56

Erio:gonum. umbella,tum Torr.

Sandy soil under Ju.niperus utaltensis.., Horse Trail Can.yon smmit, Weber formation, 6» 000 ft. alt. , Welsh 355. Poluonum avlculare L.

Dry slope near alkali spring along road west of divide between Island Park and Vernal, 5,700 ft .. alt., Woli and Dever 5271. Rum.ex crispus L.

. Second;8-ry species in ~us tremuloides stand near Doug Chew 1s .Cabin, alluvium, 7,400 ft. at •., Welsh 423.

R.um.:exhymenosef&!us Torr. Hills east t>f Dinosaur Quarry,. 5,008 ft,. alt • ., Graham. 7569. CHENOPODIACEAE

AtriP!ex eanescens (Pursh) .Nutt .• Sand dunes over for.mations in the southw.est portion of the Monument, alluvium (derived £ram the Navajo sandstone), 5,000 ft. alt., Welsh 450.

Airiplex confertifolia (Torr, &t Ftem.) Wats .. Bas.e of clay slope near Orchard Creek Draw, Manco.a shale form• ation., 4,770 ft. alt., Welsh 169 • . A.triplex corrugata Wats. East~facin_g slope on gray clay, near Orchard Creek Draw, .Mancos shale formation, 4-1770 ft. alt., Welsh 33. This is th..e dominant species on the Mancos.

A.uiplex nuttallii S. Wats. South-facing slope on gray ela.yt. south"R'est monument bounda.ry, .Mancos shale formation, -4.,800 ft.. alt. , Welsh 408. Atriplex sacc:aria Wa.ts. East-facing clay slope, near southwest monument bowidary, Mancos sh.ale formation 4, 8.00 ft. alt. , Welsh 406 .•

Atriplex wolfi Watson

Dry banks, Mc Kee Spring, Woli and Dever 5250. 57

Chenoeodiu.m £remontii S. Wats.

High g.round near sandy alkaline seep at Mc Kee Spring, alluvium. 5, 250 ft. alt., Welsh 336 ..

Chenopo4iu.m s!?:ucu.m L. var. Salinum (Stand!. ) Aellen Dry bed of wash, Mc Kee Spring, Wolf and Dever 5260.

Chenopodium incanum (Watts.) Heller

One mile east 0£ Headquarters, Dakota sandstone, W. A. Weber 5369. Eu.rotia Ianata (Pursh.) Moq.

East side of Green River, Island Park, 5, 000 ft. alt. , Graham ~185.

Grazia s;pinosa (Kook. ) Moq. Small sandy flat along wash, Orchard Creek Draw, Curtis £orm ... ation.1 5,000 £t. alt., Welsh 302.

Grazia brandegei A.. Gray

Dry clay slope, 4,800 ft. alt., B. F. Harrison 7755.

Kochia americana.S. Wats.

Gravely outcrop, Orchard Creek Draw, Morrison formation, 4,800 ft. alt., Welsh 452. ·

Kochia scoparia (L. ) Schrad.

Salt marsh, Mc Kee Springs, Wolf and Dever 5251.

Monolepis pusilla Torr.

Between Dinosaur Quarry and Green River, 4, 800 ft. alt., Graham 77 42. Monolepis nuttalliana (Schult. ) Greene

Sandy flat near Doug Chew's Cabin, Weber formation, 7, 40Q ft. alt. , Welsh 500.

. Salsola kali L.

Observed growing in open spaces between plants, especially on alluvium v.rhere grazing is heavy, no samples have been collected. 58

Sarcobatus vermiculatus (Hook. ) Torr.

Clay loam flat west of Rainbow Park, alluvium, 5, ZOO ft. alt., Welsh 326.

Suaeda torreyana S. Wats.

Clay loam flat west of Rainbow Park as understory of Sarcobatus vermiculatus, alluvium, 5, ZOO ft. alt., Welsh 325.

NYCTAGINACEAE

Abronia fragrans elliptica Heimerl.

West-facing slope as a secondary species of Artemisia tridentata, Park City formation, 5, 800 ft. alt., Welsh 284.

Mirabilis linearis (Pursh) Heimerl.

Sandy flat at cliff base, Orchard Creek Draw, Alluvium, 4,800 ft. alt., Welsh 440.

Tripterocalyx micranthus (Torr.) Hook.

Sandy flat, near Beaches Draw. Curtis formation. 5,400 ft. alt., Welsh 514.

CARYOPHYLLACEAE

Arenaria congesta Nutt.

Secondary species among Populus tremuloides, near Doug Chew's Cabin, 7,400 ft. alt., Welsh 472.

Arenaria uintahensis A. Nels.

Sandy east-facing slope near Split Mountain Gorge Campground, Moenkopi formation, 5, 100 ft. alt.» Welsh 303.

RANUNCULACEAE

Stellaria jamesiana Torr.

Secondary species among Populus tremuloides, near Doug Chew's Cabin, 7,400 ft. alt., Welsh 473.

Clematis ligisticifolia Nutt.

Along Cottonwood Wash, climbing on Populus spp. and .Rhus trHobata, alluvium, 5,000 ft. alt., Welsh 381.

Delphinium nelsoni Greene

West-facing slope as a secondary species among Jµniperus 59 utahensis, head of Red Wash, Park City formation, 5, 800 ft. alt., Welsh 209.

Ranunculus cymbalaria Pursh

Wet sand bar adjacent to a small pool of water, along the Gre~n River, alluvium, 5,000 ft. alt., Welsh 396.

BERBERIDACEAE

Berberis repens Lindl.

Mound of sand at the base of east cliff, in a small canyon, Orchard Creek Draw, Navajo sandstone, 5,000 ft. alt., Welsh 186.

CAPPARIDACEAE

Cleome lute.a Hook.

Clay flat, as a secondary species in the mixed desert shrub association, alluvium (derived from Mancos shale), 4, 770 ft. alt., Welsh 164.

Cleome serrulata Pursh. ·

Around corrals and along road, Doug Chew' s Cabin, 7 • 200 ft. alt., Welsh 418.

CRUCIFERAE

Arabia demissa Greene

Under Juniferus utahensis, Red Wash, near Split Moutain, Moenkopi form.ation, W. A. Weber 5356. Arabia glabra (L. ) Bernhardi

Sandy soil, in Populus tremuloides stand, near Doug Chew's Cabin, Weber formation, 7,400 ft alt. , Welsh 490.

Arabie holboellii retrofracta (Graham) Rydb.

Dinosaur Quarry, 5,000 ft. alt., Graham 7554.

Arabie perennans Watson

Orchid (Mud) Springs Canyon (Orchard Creek Draw), 5,000 ft. alt., Graham 7749.

Arabis pulchra M. E. Jones

Sandy east-facing slope, Orchard Creek Draw, Dakota sandstone, 4, 800 ft. alt., Welsh 177. 60

Arabis selbyi Rydb.

East-facing slope above Split Mountain Gorge Campground, Bishop conglomerate, 5,000 ft. alt., Welsh 37.

Caulanthus crassicaulis (Torr.) Wats.

Carmel formation, west of Split Mountain Gorge, W. A. Weber 7397.

Capsella bursa-pastoris (L.) Medic.

Sandy soil, among Populus tremuloides, near Doug Chew's Cabin, Weber formation, 7, 400 ft. alt. , Welsh 477.

D-escurainia pinnata (Walt. ) Britt.

Understory in ju.niper-pinyon forest, west-facing slope, head of Red Wash, Weber formation, 5, 800 ft. alt., Welsh 221.

Descurainia pinnata brachycarpa (Richard.) Detling (ssp.)

North of Dinosaur Quarry, 5,500 ft. alt., Graham 7711.

Descurainia pinnata halictorum (Cockerell} Detling (ssp.)

Northeast of Dinosaur Quarry, Peterson s. n.

Descurainia sophia (L.) Webb.

Headquarters area, Wolf and Dever 5226.

Draba reptans (Lam. ) Fernald

East-facing slope as part of the understory of Juniperus utahensis, Bishop conglomerate, 5,200 ft. alt., Welsh 126.

Draba oligosperma Hook.

Rocky north-facing slope, north of Doug Chew's Cabin, Weber formation, 7, 400 ft. alt. , Welsh 507.

Erysimum asperum (Nutt. ) D. C.

Sandy slope as part of the understory of Juniperus utahensis, Little Rainbow Park, Navajo sandstone, 5,000 ft. alt., Welsh 153.

Erysimum capitatum (Dougl. ) Greene

Sandy flat, Orchard Creek Draw, alluvium, 4, 900 ft. alt., Welsh 197. 61

Lepidium densiflorum ramosum (Nels.) Thell.

Hills east of Dinosaur Quarry, 5,000 ft. alt., Graham 7576.

Lepidium montanum Nutt.

Sandy flat, as part of the understory of Artemisia tridentata, Orchard Creek Draw, alluvium., 4,900 ft. alt., Welsh 198. Lesquerella ludoviciana (Nutt.) S. Wats.

Sandy slope under Juniperus utahensis, Orchard Creek Draw, Navajo sandstone, 4, 900 ft. alt., Welsh 185. Lesquerella subumbellata Rollins

West-facing slope, as part of the understory of Artemisia tridentata, head of Red Wash, Park City formation, 5, 800 ft. alt., Welsh 212.

Malcolmia africana (L. ) R.

Sandy flat near Do~g Chew's Cabin, Weber formation, 7,400 ft. alt. , Welsh 494.

Physaria australis (Payson) Rollins

Base of slope among boulders, Orchard Cl'eek Draw, Frontier formation, 4, 770 ft. alt., Welsh 84.

Rorippa hispida (Desv. ) Britton

Flats south of headquarters road, 4, 750 ft. alt., Wolf and Dever 5233.

Rorippa nasturti.um-e.quaticum (L. ) Schinz. 8t Thell.

Moist, big draw, tributary to Jones Hole, Bradley 5343.

Rorippa sinuata (Nutt. ) A. S. Hitchcock

Banks of Green River south of headquarters, Wolf and Dever 5231.

Sisymbrium elesans (Jones} Payson

Steep north-facing sandy slope, Orchard Creek Draw, Frontier formation, 4, 770 ft •. alt., Welsh 85.

Sisymbrium linifolium Nutt.

Along a wash among Artemisia tridentata, Orchard Creek Draw, alluvium, 4 1 800 ft. alt., Welsh lOl. 6.2

Stanleya pinnata (Pursh) Britton

West-facing slope among Juniperus utahensis, near Split Mountain Gorge, Moenk.opi formation, 5,000 ft. alt., Welsh 376. Streptanthella longirostris (S. Wats. ) Rydb. Among boulders on south-facing slope, Orchard Creek Draw, Dakota sandstone, 4, 800 ft. alt., Welsh 94.

Thelypodium lilacinum Greene Sandy floor of Red Wash, Bradley 5343. Thelapodium rhomboideum Greene Steep eaat-facin1 sandy slope among Bhus radieana and Bhua trilobata, alluvium, Split Mountain Gorge Camp1round, 4, 800""lr."l.lt. , Weiah430. CRASSULACEAE Sedum atenopetalum Pur ah

Crevaa1e1 on Weber formation, neaz Dou1 Chew 11 Ca'bin, 7 ,.400. ft, alt, , Welah 491, SAXIFR.AG.A.CEAE Fend.lerella utahenail (S, Wat,.) Heller We1t-facin1 •lope a1 u.nder1tory amona J~eru.1 u.t&hen1l1, ea1t aide of Qreen IJver, Split Mountain Qor1e,0Ser formation, 4,900 ft, alt,, Wel1h 372. Heuchei'a pai'vU'olia Nutt, Occur• a1 part of the \lnder1tory 0£ the juniper•plnyon !ore1t, Hor1e Trail Canyon, Weber formation, 6,000 ft. alt., Welah 245. Philadelphu1 microphyllu.1 Oray We1t-facin1 1lope •• under1tory amon1 Jun~eru1 \lt&hen1ia, ea1t aide of Oreen lUver, Split Mountain Gorae,eSer torm-.Uon. 4,900 lt, alt,, Wel1h 400 •

.A.monaArtembia trident&ta alona a water cour1e, Beaclun Draw, alluvium, 8, 0.80ft. an., Wellh 66. 63

ROSACEAE

Amelanchier pallid.a Greene

East side of Green River near Island Park, 5,000 ft. alt., Graham 9196.

Amelanchier utahensis Koehne Gravel slope among Ju.niJierus utahensis, Little Rainbow Park, alluvium, 5,000 ft. alt., Wels 139.

Cercocarpus intricatus_ S. Wats.

South.facing slope, as understory among juniper pinyon forest, Horse Trail Canyon, Morgan formation, 5, 800 ft. alt., Welsh 241.

Cercocarpus ledifolius Nutt.

Grqwing on rock outcrops with a southern exposure on Blue Mountain Plateau, Weber formation, 7,400 ft. alt., Welsh 513.

Cercocarpus montanus Raf.

Sandy south-facing slope, Little Rainbow Park, Navajo sandstone, 5,000 ft. alt., Welsh 150. lvesia gordonii (Hook.) T. &t G.

Crevices on Weber formation, near Doug Chew 1s Cabin, 7,400 ft. alt. , Welsh 488.

Potentilla anserina L.

Banks of Green River 1 south of headquarters, 4, 700 ft. alt., Woli and_Dever 5230.

Potentilla gracilis Dougl.

Secondary species among Populus tremuloides, near Doug Chew's Cabin, Weber formation, 7,400 ft. alt., Welsh 474. Prunus virginiana, var. melanocarpa (A. Nels.) Sarg.

Occurs as understory of Po,ulus tremuloides, near Doug Chew 1s Cabin, alluvium, 7,200 ft. alt., elsb 414.

Purshia tridentata {Pursh) D. C.

Secondary species among Pinus ponderosa, near Doug Chew's Cabin, Weber formation, 7,400 ft. alt., Welsh 492. 64

Rosa woodsii Lind.I.

Occurs as part of the understory of Po1mlus tremuloides, near Doug Chew's Cabin, alluvium, 7,400 ft. alt., Welsh 413.

LEGUMINOSAE

Astragalus asclepiadoides Jones

Sandy hills in Red Wash, Bradley 5446.

Astragalus bisulcatus (Hood) Gray

Grazed pasture, Rainbow Park, alluvium., 5,000 ft. alt., Welsh 320.

Astragalus ceramicus Sheld.

Sandy flat along Green River, Split Mountain Gorge, alluvium, 5., 100 ft. alt •• Welsh 238.

Astragalus chamaeleuce Gray

Gravely slope, Little Rainbow Park, Moenkopi formation, 5,000 ft. alt., Welsh 140.

Astragalus chloodes Barneby

Am.ong boulders on south-facing slope, Orchard Creek Draw, Dakota sandstone, 4, 800 ft. alt., Welsh 93.

Astragalus conf ertiflorus A. Gray

Sandy slope, west of Island Park, Morrison formation, 5, 200 ft. alt., Welsh 116.

Astragalus cymboides Jones

Hills east of Dinosaur Quarry, 5,000 ft. alt., Graham 7575.

Astragalus diversifolius Gray

Sandy slope, near Split Mountain Gorge, Shinarump conglomerate, 5, 700 ft. alt., Welsh 259.

Astragalus duchesnensis Jones

Sandy hills east of west draw, headquarters area, Bradley 5307.

Astragalus Flavus Nutt.

East of Dinosaur Quarry, Peterson s.n. 65

Astragalus geyeri Gray

Flats south of headquarters area, Bradley 5356.

Astragalus inflexus Dougl.

Hills east of Dinosaur Quarry, 5,000 ft. alt., Graham 7573.

Astragalus moencoppensis Jones

North of Dinosaur Quarry, 5,500 ft. alt., Graham 7718.

Astragalus purshii Dougl.

Sandy west-facing slope, head of Red Wash, Park City formation,

5 1 800 ft, alt. ,· Welsh .214.

Astragalus saurinus Barneby

Clay bank along wash, Orchard Creek Draw, Morrison formation, 4., 770 ft. alt., Welsh 172.

Astragalus spatulatus Sheld.

Sandy slope, Split Mountain Gorge, Weber formation, 6,000 ft. alt. , Welsh 252.

Astragalus thompsonae 5. Wats.

Gravely slope among Artemisia tridentata, head of Red Wash, Park City formation, 5, 800 ft. alt. , Welsh Z8Z.

Glycyrrhiza Lepidota Pursh

Secondary species in a Distichlis stricta meadow, Rainbow Park, alluvium, 5,000 ft. alt., Welsh 338.

Hedysarum boreale Nutt.

Rocky ridge above Split Mountain Gorge Campground, Bishop conglomerate, 5,000 ft. alt., Welsh 270.

Lupinus argenteus Pursh

· Small flat, part of the understory of Juni~erus utahensis, Orchard Creek Draw, Entrada formation, 4, 90 lt. alt., Welsh 183.

Lupinus greenei A. Nels.

Bottom of draw behind headquarters, W. A. Weber 542.8. Lupin.us pusillus Pursh

Steep east-facing slope, Orchard Creek Draw, Curtis .formation, 4, 800 ft. alt. • Welsh 17 5.

Lupinus rubens Rydb.

Draws and £lats 2 miles east of headquarters, W. A. Weber 5428.

Medicago sativa L.

Noted growing in cultivated fields in Island Park ancl along the Green River where it has escaped £rom cultivation, no specimens were collected.

Melilotus alba Desr.

Noted growing on sandy bank along Green River, Rainbow Park, alluvium, 5,000 ft. alt., no specimens were collected.

M.elilotu.s o!ficinalis (L.) Lam.

Same as for Melilotus alba.

Psoralea megalantha Woot. & Standl.

Sand along drainage bottoms, near Split Mountain Gorge Camp- ground, Moenkopi formation, 5,000 ft. alt., Welsh 273.

Psoralea sp.

Sand dunes along ridge west of Orchard Creek Draw, alluviu.m (Navajo blow sand). 4, 800 ft. alt., Welsh 446.

Thermopsis montana Nutt.

Moist clay at the base of the Mowry shale formation, north of road near Rainbow Park, 5, 100 ft. alt., Welsh 158 ..

Trifolium gymnocarpon Nutt. North of Doug Chew 1s Cabin, north-facing sandy slope, Weber formation, 7, 500 ft. alt. , Welsh 508.

GERANIACEAE

Geranium. nervosum Rydb.

Occurs as part of the understory in Popu.lus tremuloides, near Doug Chew's Cabin, alluvium, 7. 400 ft. alt., Welsh 425. 67

LINACEAE

Linum lewisii Pursh

West-facing slope as part of the understory of Artemisia tridentata, head of Red Wash, Park City formation, 5, 800 ft. alt.-;-- We!sh 294.

EUPHORBIACEAE

Euphorbia fendleri T. & G.

Sandy ridge near Split Mountain Gorge Campground, Moenkopi formation, 5,000 ft. alt., Welsh 378.

Euphorbia robusta. (Eng elm. ) Small

East-facing sandy slope near Island Park road, Curtis forrnation, 5,000 ft. alt., Welsh 103.

ANACARDIACEAE

Rh.us radicans L.

Sand at the base of east-facing cliff, Split Mountain Gorge Campground, Weber formation, 5,000 ft. alt., Welsh 367. -----Rh.us trilobata Nutt. Sandy bank along stream course in Beaches Draw, alluvium, 5,050 ft. alt., Welsh 64.

CELASTRACEAE

E'orsellesia meionandra (Koehne) Heller

Sandy west-facing slope, Split Mountain Gorge, Weber formation, 5,000ft. alt., Welsh 401.

Pachystima myrsinites (Pursh} Raf.

West base of Blue Mountain, east side of Green River, Island Park, 5,300 ft. alt., Graham. 9197.

ACERACEAE

glabrum Torr.

North-facing slope, north of Doug Chew's Cabin, Weber form.- ation, 1, 500 ft. alt., Welsh 510. 68

negundo L.

Sandy soil along a stream course, Orchard Creek Draw, alluvium, 5, 000 ft. alt. , Welsh 187.

MALVACEAE

Sphaeralcea cocclnea (PursJi) Rydb.

Clay soil at the base of slope, Orchard Creek Draw, Mancos shale formation, 4, 770 ft. alt., Welsh 161.

Sphaeralcea parvifolia A. Nels.

Red Wash above Island Park, 5,200 ft. alt., Graham 9159.

TAMARICACEAE

Tamarix gallica L.

Wet sand bar in Green River, Rainbow Park, alluvium, 5,000 ft. alt., Welsh 310.

VIOLACEAE

Viola nuttallii Pur sh

South-facing gravel slope, north of Rainbow Park, Bishop conglomerate, 5, 100 ft. alt., Welsh 133.

nephrophylla Greene

Sandy alkaline seep, Orchard Creek Draw, alluvium, 5,000 ft. alt., Welsh 469.

LO.ASACEAE

Mentzelia albicaulis Doug!.

Sandy soil near Doug Chew' s Cabin, alluvium., 7, 400 ft. alt. , Welsh 502.

M.ent.zelia humulis (Gray) Darlington

Sand in bottom of small ravine, near Split Mountain Gorge Campground. Moenkopi formation, 5,000 ft. alt., Welsh 380.

Mentzelia dispersa Wats.

Two miles west of headquarters, Mancos. shale, W. A. Weber 5324. 69

CACTACEAE Echinocactus simpsonii Engelm.

Noted growing on gravely slope west o£ Split Mountain Gorge campground. Bishop conglomerate, 5,000 ft. alt., no specimens were ·:collected:-

E.chinocereus octacanthus (Muhlenpfordt) Birtt. & Rose

R.ed Wash, above Island Park, 5, .ZOOft. alt.,. Grab.am 9146.

Qpuntia phaecantha. Eng elm. Sand, along a wash,, Horse Trail Canyon drainage, alluvium, 5,500 ft. alt., Welsh 363 • . ELEAGNACEAE Sp.epherdia argentea (Pur sh) Nutt.

Sand at the base of east--facing cliff,, Split Mountain Gorge Campground, Weber formation, 5,000 ft. alt., Welsh. 371. ONAGRACEAE

Gayofhytum nuttallii T. & G.

Sandy slope near Doug Chew's Cabin ... Weber formation, 7,400 ft. alt., Welsh 499.

Oenothera eaespitosa Nutt.

Shallow sandy soil, along drainage bottom, south-facing slope, in Split Mountain Gorge, Morgan formation, 5,800 !t. alt., Welsh 231.

Oenothe ra· contorta. Dougl.

Between Dinosaur Quarry .and Green River, 4, 800 ft. alt. , Graham 7739.

Qenothera hooked T. &: G.

Wet gully bottom., growing with Phragmite.s cammunis, Orchard Creek Draw, alluvium, 4., 800 ft. alt., We1sh 4j7_

Oenothera minor. (A. Nels. ) Munz

Between Dinosaur Quarry and Green Rh·er., 4., 800 ft. alt. , Graham 7741. 70

Oenoth.era. scaP?idea Nutt .•

Clay soil at the base 0£ slope, 0:rcha.rd Creek Draw, Mancos shale £ormation, 4, 770 £t. alt. 1 Welsh 162.

Oenothera tricho.calp Nutt. Southeast-facing gravel covered slope, Park City formation, head of Red Wash, 5_,800 it. alt., Welsh .Z80. HALORAGIDACEAE

Hippuris vulgaris L.

Small pool along Green River:1 Split Mountain Gorge, alluvium., 5,008 ft. alt •., Welsh 397. UMBELLIFERAE

Berula erecta (Huds. ) Coville

West s.tream bank at Jones Hole., Bradley 5348.

Cymopterus acaulls (Pursh) R.af.

Hills east of Din.o.saur Quarry, 5,000 £t. alt., Graham 7574.

9Im:opterus bulbosus A. Nels. East-facing clay slope, Orchard Creek Draw, Mancos shale formation., 4 .• 770 ft. alt., Welsh 35.

9%!!1:,oPterus. duch.esnense Jones

Steep east-facing sandy slope, Orchard Creek Draw, Curtis for.mation, 4,800 ft. alt., Welsh 180 .. gym.opterus fendleri Gray

Low hogbacks along road Z miles east of headquarters, W. A. Weber 5426.

CE!iopterus pu1'.'E_U;reusS. Wats.

South•facing sandy slope" Little Rainbow Park, Navajo sandstone,_ 5,050 ft. alt •• Welsh 31.

Lom.atium srayi Coult. $:t Rose

South-facing gravely slope,.· Split Mountain Gorge, Morgan formation, 6, 000 ft. alt. , Welsh 234. 71

Lomatium simplex (Nutt. ) Macbr.

North o£ Doug Chew• s Cabin, sandy soil, Weber sandstone, 7., 500 ft. alt., Welsh 511.

Ptecy:xia terebinth;ina (Hook. ) Coult. 8t Rose

North of Dinosaur Quarry, 5., 500 ft. alt •• Graham 7712. CORNACEAE

Cnrnu.s stolonifera Michx.

East bank of Green River, Island Park, 4,, 900 ft. alt. , Graham 9186. ERICACEAE Arctostaeylos patula Greene

Collected on the south edge o£ Blue Mountain., understory in Pinus ponderosa., Weber sandstone, Welsh 513. OLEACEAE Fraxinus anomala Torr.

Sandy soil, occurs with Juniperus utahensis and Cercoc.ar;pus montanus, Little Rainbow Park, Navajo sanastone, 5, OODft. alt:, Welsh 151. APOCYNACEAE

A:maonia jonesii V/ oodson

North-facing slope, near Split .Mowttain Gorge Campground, Chinle formation, 5,000 £t. alt., Welsh Z61.

A:eo2um cannabinum L.

Pasture, clay soil, associated with Disticltlis stricta, alluvium, Rainbow Park, 5, 000 ft. alt. , Welsh 340 •

. ASCLEPIADACEAE

Ascle;pias speciosa Torr.

Sand at the ba.se of east ...facing cliff.,. Split Mountain Gorge Campground., Weber formation, 5,000 ft. alt .. , Welsh 370.

A.sclepias crntoceras S. Wats.

Steep east ...facing sandy slope, Orchard Creek Draw, Curtis 72 formation> 4,800 ft. alt., Welsh 173.

POLEMONIACEAE

Collomia linearis Nutt.

Secondary species among Populus tremuloides, near Doug Chew's Cabin, alluvium, 7, 400 £t. alt. " Welsh 480. Eriastrum diffusum (Gray) Mason

Clay soil at the base 0£ slope, Orchard Creek Draw:, Mancos shale formation, 4, 770 ft. alt., Welsh 162.

aggregata (Pursh) Spreng.

Sand, a't summit of Horse Trail Canyon, Weber formation, 6,000 ft. alt. , Welsh 250.

Gilia ea.lcarea M •. E. Jones

Limestone ledge, Split Mountain Go~ge, Morgan formation, 6,000 ft. alt. , Welsh 228.

congesta Hook.

Headquarters area, sandy valley east of Dinosaur ledge, Bradley 5354.

polycladon Torr.

One mile east of headquarters, Dakota formation, W. A. Weber 5374.

pumila Nutt. Sand dunes on north side of Green River, W. A. Weber 5439.

roseata Rydb.

Sandy clay soil, steep slopes back of headquarters, Wolf and Dever 5010.

sinuata Dougl.

Red Wash above Island Park, 5.,200ft. alt., Graham 91.-49.

9J:!!m:oste:ds erY\].].a (B.ydb.) Heller

Sandy flat near poug Chew's Cabin, Weber formation, 7,400 ft. alt. , Welsh. 497. Leptpdactylon P!1!1:Sens (Torr. ) Rydb. South-£acing slope am.ong boulders, Horse Trail Canyon drain• age, Shinarump formation, 5,700 ft. alt., Welsh 258. 73

Microsteris humulis (Doug!. ) Green

Near Doug Cb..ew1s Cabin, sandy flat, Wel>er formation,. 7,400 ft. alt., Welsh 504.

NaYB.rreUa brewer! (Gray) Greene

Near Dtmg Cb.ew's Cabin, sandy flat Weber formation" 7., 400 ft. alt., Welsh 501.

Phlox h.oodii Rich.

North..-facing sandy slope, as understory o£ Juniperus utahensis and Am.elanc:h.ier utahensis, Beaches Draw, Chinle lormatlon, 5,050 ft. alt . ., Welsh. 70.

Phloxlon;lioliaNutt. Among boulders on west-facing .slope, head o£ Red Wash., Weber formation, 5) .800 ft. alt. , Welsh 215. HYDROPHYu...ACEAE

Na.ma densum. Lemm.on

Sand dunes on north. bank of Green River, W. A. Weber 5434.

Phacelia eorrugata A. Nels.

Sandy east-facing slope., hills wes.t o£ Island Park, 5., 200 ft. alt. , Welsh 104. Pha.celia dem.is sa Gray

Clay soil at tlle base 0£ slopet Orcll.a.rd Creek Draw, Mancos $hale formation, 4,770 ft. alt., Welsh 159 ..

Pha.~ella iv,esiana. Torr. Steep slopes, in shade of Juniperus utahensis, Park City form.a ... tion, between headquarters and SpllfMountaln,, W.A. Weber 5351.

Phacelia sericea var. biennis (Nels.) Brand

Sandy soil in Po~ulus tremuloides stand,J near Doug Chew 1s Cabin, alluvium, 7,40 ft .. alt., Welsh 4PJ. BORAGINACEAE

Cryptantha breviflora (Osterhout) Payson ( Gravely soil alo-ng road near Island Park.- Bishop conglom.erate, 5. ZOO ft. alt . ., Welsh ll

C!tetantba fendleri (Gray) Green

Sandy alluvium, near Doug Chew's Cabin, 7,400 £t. alt., Welsh 493.

Cryptanth.a. (A. Nels. ) Payson

South-facing sandy slope, Orchard C:reek Draw, Frontier formation 4,770 ft. alt., Welsh 82.

Cryptantha fiavoculata (A. Nels.) Payson

Eas.t-facing gravel covered slope, near Split Mountain Gorge Campground, Bishop conglomerat,. s. 000 ft. altq Welsh 4'". Crypta ntha graeilis Osterh.

Gentile south-facing sandy slope, O.rcha.rd Creek Draw, alluvium, 4,900 ft. alt., Welsh 196a.

Cryptantha kelseyaea.. Greene

Split Moun.ta.in Gorge Campground,. sandy wash, 5, 250 ft. alt. , Wolf and Dever 5099.

C!Jl?tantha etteraonii (Gray) Greene Low hogbacks between Split Mountain and headquarters, W. A. Web.er 5423. C:eyptantha pterocaga (Torr.) Greene

Frontier £ormation,, headquarters gulch, W. A. Weber 7405.

C!J:Ptantha. recurvata Coville Frequent.along trail to Dinosaur Ledge, :Morrison formation, neal' headquarters, W ..A. Weber 5445. C~tha. rollinsii I. M. Johnston

Hogbacks between headquarters and Split Mountain Gorge, W. A. Web,er 5345. LaEP!1eredowskii (Hornem. ) Green Gravely soil west of Island Park., Bishop conglomerate, 5, 280 ft. alt. , Wel$11 117.

La~ texana..{Scheele) B:ritt.

South-facing sandy slope, Orchard Creek D:raw, Dakota sandatone., 4,800 ft .• alt •. , Wel$h 95. 75

Lithosperm.um incisum Lehm.

South-facing sandy slope, Orchard Creek Draw, Frontier formation, 4, 770 ft.. alt.. ,, W elah 86 ..

Lith,u1permum ruderale Doug!.

Sandy fla.t near Doug Chewls Cabin, Weber formation, 7,400 ft. alt. , Welsh. 489.

Mertensia oblongifolia {Nutt .• ) G. Don

Sand, as part of the under story in juniper ...pinyon forest ... summit of Horse Trail Canyon, Weber formation, 6.,000 ft. alt., Welsh Z44. VERBENACEAE

Verbena bracteata Lag. 8t R.odr. Dry clay slope, 4., 800 ft. alt. • B. F. Harrison 77 54.

LABIATAE

M.entha al"vensis L.

Wet sand around small pool along Green River, Split Mountain Gorge-'. alluvium, 5, 000 ft. alt., Welsh 398. SCROPHULARI.A.CE.AE

Castilleja ehromo:aa A. Nels. East.facing gravel covered slope, near Split M.cmntain Gorge Campground; Bishop eonglom.erate. 5,000 ft. alt •., Welsh 44.

CastilleJe miniata. Douglas I Sandy wet section 0£ Red Wash., Bradley 5359.

Collin.sia e,rviflol"a Doug!.

Secondary species in Populus tremuloides stand, near Doug Chew's Cabin ... Weber formation, 7,400 ft. alt., Welsh 481. Mimulus J;Juksdorfii A. Gray

Sandy flat near Doug ChewJs Cabin, Weber formation, 7,400 ft. alt., Welsh 496.

Penstemon arenicola A. Nels.

West-facing sandy slope, head 0£ Red Wash., Weber formation, 5,800 ft. alt., Welsh 218. 76

Penstemon cya.nocaulls Payson

Small sandy areas on outcrop of Weher formation, near JlQug Chewls Cabin¥ 7,400 ft. altq Welsh 470.

Penstemon fremontii T. & G.

Upper slopes of Morrison formation, headquarters area, W. A. Weber 7396.

Penstemon ~ch.umyllus A. Gray

North of Dinosau.:r Quarry, 5, 500 ft. alt • ., Graham 7713.

5er0fhnlaria lanceolata Pursh

Sandy soil among P!fulus tremuloide s, near Doug Chew 1s Cabin, Weber fo.rmation, 7,400 ft. all., We1sli 424. Veronica peregrina. L.

Sandy soil near Doug Chew 1s Cabin, Weber formation, 7,400 ft. alt., Welsh 498.

OROBANCHACE.A.E

O:ro'.banch.e ludovicia.na. Nutt.

Hills west of Island .Park, Bradley 5339.

RUBIACEAE.

Galium eoloradoenae W. F. Wright

Nor:th-.facing .sandy .slope, near Split Mountain. Gorge Campground,. . Shina.r.um.p conglomerate., 5., 000 ft. alt., Welsh 276. '

Galium. bifollu.m Wats.

Secondary species among ~ulu.s tremuloides., near Doug Chew 1s Cabin, 7, 400 ft. alt. , Welsh 4 7 • PLANTAGINACE.AE

Pla.ntago pu.rshil Raem. & Schult.

Sandy slope among Ju.niperus utahensis., head of Red Wash., Park City formation, 5,800 £t. alt., Welsh 286. CAPRIFOWACEAE

Sym.phorlcarea lengiflorus Gray Gravel covered £lat, near road to Harpers Corner, Blue Mountain Plateau, alluvium; T, 400 ft. alt., Welsh. 426. 77

Sz!teoricaJ;pos occidentalis Hook.

Sand.1 along out'Wash plain, as under story of Populus fremontii, Ra.in.bow Park, alluvium, 5,000 ft. alt., Welsh 315.

COMPOSITAE

Achillea lanulosa Nutt.

Occurs as part of the understory in Populus trem.uloides, near Doug Chew•s Cabin, alluvium, 7,400 £t. alt., Welsh 417. 4:;oseris glauca (Pursk) D. Dietr. West-facing sandy slope, head of R.ed Wash, Park City formation, 5., 800 ft. alt., Welsh. 208.

An.tennaria dimor!1!! (Nutt .. ) T. & G.

Solµlt-facing sandy slope, Little R.ainl>-ovrPark, Navajo sandstone, 5,, 000 ft. alt. , Welsk 15n.

Ar:temisia dracunculus glauca (Pallas) H. & C ..

Stationary dune ,aand, west ridge of Orcllard Creek Draw, alluvium.., 4, 900 ft. alt •. , Welsh 44 7. Artem.isia lud.Qviciana Nutt.

Mowry shale outcrop, Or~d Creek Draw, 4, 800 ft. alt. , Welsh 455.

Artem.isia spinescens D. C .

.Steep souill•facing sandy slope.1 Orchard Creek Draw, Frontier formation. 4,770 ft. alt., Welsh 88. Artemisia tridentata Nutt. South..-facing gravel covered slope, north af Rainbow ParkJ Bishop conglomerate,, 5,100 ft. alt., Welsh 138. -Aster adsce:ndens Lindl. Stationary dune sand., we st ridge of Orchard Creek Draw alluvium, 4,900 ft. alt., Welsh. 447 ..

Aster arenosus Blake Gravel covered south.facing slope, Split Mountain Gorge, .Mor- gan formation, 5, 300 ft. alt,., Welsh Z30. Aster leuea.n.themifolius Greene Dinosaur Quarry, 5,000 ft. altq Graham 6674. 78

Aster venustus M. E. Jones

North of Dinosaur Quarry, 5,500 ft. alt. 1 Graham 7717.

Aster ?o/lorrhiza T. & G.

Steep east-facing sandy slope., Orchard CreekDraw, Curtis formation, 4, 800 ft. alt., Welsh 178.

Bahia oblongifolia A. Gray

Clay along drainage, Horse Trail Canyon, Morrison formation_. 5,400 ft. alt., Welsh 346.

Balsamorhiza sas;ittata (Pu.rah) Nutt.

Sandy soil, secondary species in Pinus ponderosa, near Doug Chew's Cabin, Weber formation., 7,400 ft. alt. ~Weisli 484.

Brickellia watsonii Robinson

Sandy clay soil, steep slopes, ravine back of headquarters, 5, Z.50 ft. alt., Wolf and Dever 5007.

Chaenactis douglasii (Hook. ) H. & A.

West-facing gravel covered slope, west of Island Park, Bishop conglomerate, 5,200 ft. alt .• Welsh 313.

Chaenactis stevioide s Hook.

Clay soil at the base of slope, Orchard Creek Draw, Mancos shale formation, 4, 770 ft. alt., Welsh 163.

Chrysopsis villosa (Pursh) Nutt,

Sand at the base of east-facing cliff, Split Mountain Gorge, Weber formation, 5,000 ft. alt., Welsh 373.

Chrysopsis villosa var. hiseida. (Hook.) Gray

Gravely west-facing slope, Orchard Creek Draw, Dakota sandstone, 4, 800 ft. alt. , Welsh 454.

Chrysothamnus nauseosus (Pallas) Britt.

Among Populus fremontii along Green River, Rainbow Park, alluvium, 5,000 ff. alt., Welsh 318.

Chrysothamnus viscidiflorus (Hook.) Nutt.

Steep east-facing sandy slope, Split .Mountain Gorge Campground, Weber formation, 5,000 ft. alt., Welsh 432. 79

Cirsium undulatum (Nutt. ) Spreng.

Sandy drainage bottom, Horse Trail Ca:p.yon drainage, alluvium, 5., 500 ft. alt., Welsh 343. 1

Crepis intermedia Gray

Red Wash, above Island Park, 5,200 ft. alt., Graham 9157.

Enceliopsis nudicaulis (Gray) A. Nels.

Steep slopes of Park City formation, north side of Red Draw., between Headquarters and Split Mountain Gorge, W. A. Weber 5349.

Enceliopsis nutans (Eastw.) A. Nels.

Clay soil at the base of slope, Orchard Creek Draw, Mancos shale formation, 4, 770 ft. alt., Welsh 170.

Erigeron diver gens T. & G.

Sandy flat near Doug Chew's Cabin, alluvium., 7,400 ft. alt., Welsh 506.

Erigeron pumilus concinnoides (Cronquist (ssp.)

Steep east-facing sandy slope, Orchard Creek Draw, Curtis formation, 4,800 ft. alt., Welsh 170.

Erigeron utahensis A. Gray var. sparsi!olius .(Eastwood) Cronquist

Hogbacks between headquarters and Split Mountain Gorge, W. A. Weber 5268.

Franseria acanthicarpa (Hook. ) Coville

Sandy flat, Orchard Creek Draw, alluvium, 4, 800 ft. alt. , Welsh 441.

Gaillardia aristata Pursh

Small sandy areas on exposed bed-rock, near Doug Chew's Cabin1 Weber formation, 7,400 ft. alt., Welsh 486.

Grindelia aphanactis Rydb.

Island Park-Vernal road, 6,250 ft. alt., Wolf and Dever 5268.

Grindelia squarrosa (Pursh) Dunal

Sand at the base of east-facing cliff, Split Mountain Gorge Camp- ground, Weber formation, 5,000 ft. alt., Welsh 174. 80

Gutierrezia sarothae (Pu.rsh) Bxitt. & Rushy

Sand at base of south-facing slope, Orchard Creek Draw, Frontier formation, 4, 800 ft. alt., Welsh 459a. This specimen was examined by S. F. Blake, Beltsville, Maryland and has exceptionally large flowers.

Gutierrezia sarothae (Pursh) Britt. & Rushy Sand at the base of south-facing slope, Orchard Creek Draw, Frontier formation, 4, 800 ft. alt. , Welsh 458, This is the small headed variety.

Haplopappus acaulis (Nutt. ) Gray

West-facing sandy slope,, head of Red Wash, Park City formation., 5,800 ft. alt., Welsh 207.

Haplopappus nuttallii T. & G.

One mile east of headquarters, Morrison formation, W. A. Weber 5380.

Heleniu.m autu.mnale L.

Gravel bar along Green River, Split Mountain Gorge Campground, alluvium, 4, 900 ft. alt. , Welsh 460.

Helianthus annuus L.

McKee Springs, Wolf and Dever 5248.

Helianthus :petiolaris Nutt.

Sand, near saline seep, Mc Kee Spring, alluvium., 5, 250 ft. alt. , Welsh 334.

HP!ieno;pappus erioJ?Odus A. Nels. Red Wash, above Island Park, 5. 200 ft. alt., Graham 9144.

Hymenopappus filifolius Nutt.

Sandy clay soil, headquarters area, Wolf and Dever 5008.

Hymenowus lugens Green

Sandy ridge, near Split Mountain Gorge Campground, Moen.kopi formation, 5,000 ft. alt .• Welsh 305.

HymenopapPus luteus Nutt.

Headquarters area, Wolf and Dever 5823. 81

Hym.eno?o/s acaulis (Pur sh} Parker

Gravel covered south-facing slope, Split Mountain Gorge, Mor- gan formation, 5,800 ft. alt., Welsh 229.

Hymenoxys depressa (T. & G.) Gree.tie

Sandy slope, Split Mountain Gorge, Weber formation, 6, 000 ft. alt .• Welsh 254.

Hymenoxys richardsonii (Hook.) Ckll.

Sandy drainage bottom, Horse Trail Canyon, alluvium, 5,500 ft. alt._. Welsh 357.

Iva axillaris Pur sh

Sandy soil surrounding Mc Kee Spring, alluvium, 5,250 ft. alt.• Welsh 335.

Lygodesmia grandifiora (Nutt:) T. & G.

Gravel, among sagebrush, head of Red Wash, Park City formation, 5, 800 ft. alt. Welsh 283.

Lrgodesmia juncea (Pursh) D. Don.

East of Dinosaur Quarry, Peterson s. n.

M.alcothryx sonchoides (Nutt.) T. & G.

East side of Green River,· Island Park, 5,000 ft. alt., Graham 9192. Malcothrix torreyi A. Gray

Orchard Creek Draw, 5,000 ft. alt., Graham 7766. Senecio f endleri A. Gray

Sandy slope, near Doug Chew's Cabin, Weber formation,. 7,400 ft. alt. , Welsh 487 .

. Senecio integerrimus Nutt.

Sandy soil, near Doug Chew's Cabin, Weber formation, 7,400 ft. alt., Welsh 476.

Solidago canadensis L.

Wet gully bottom associated with Phragmites comm.unis, Orchard Creek Draw, alluvium, 4, 800 ft. alt., Welsh 435. 82

Solidago :tnissouriensis Nutt.

Dry sandlj>ar, east side of Green River, Split Mountain Gorge, alluvium, 5, 000 ft. alt .• Welsh 389.

Solidago occidentalis (Nutt.) T. & G.

Wet gully bottom associated with Phragmites communis, Orch- ard Creek Draw, alluvium, 5, 800 ft. alt., Welsh 4S4.

Solidago petradoria Blake

West-facing sandy slope, Split Mountain Gorge, Moenkopi formation, 5,000 ft. alt., Welsh 375.

Solidago sparsiflora A. Gray

Steep east-facing sandy slope, Split Mountain Gorge Camp- ground, Weber formation, 4,900 ft. alt., Welsh 459.

Sonchus arvensis L.

Wet gully bottom associated with Phragmites communis, Orchard Creek Draw, alluvium, 4,800 ft. alt., Welsh 436.

Stephamomeria exigua (Nutt. ) Greene.

Stationary dune sand, west ridge o£ Orchard Creek Draw, alluvium, 4, 900 ft. alt. Welsh 448.

Stephanomeria tenuifolia (Torr.) Hall

Sandy gully bottom, Horse Trail Canyon drainage, alluvium, 5,500 ft. alt., Welsh 351.

Taraxicum officinale Wiggers

Noted growing in many places in the Monument; rocky gully bottom" Morgan formation, Split Mountain Gorge, along stream course, alluvium, Orchard Creek Draw, no specimens were collected.

Tetradeia nuttallii T. & G.

Headquarters area$ red sandy clay soil, west of entrance road, Woli and Dever 5031.

Tetradymia spinosa Hook. & Arn.

Sandy flat at base of east-facing slope, Orchard Creek Draw, Curtis formation, 4,800 ft. alt., Welsh 299. 83

Townsendia incana Nutt.

Gravel covered east-facing slope, near Split Mountain Gorge Campground, Bishop conglomerate, 5,000 ft. alt., Welsh 45.

Tragopogon porrifolius ? L.

Sandy gully bottom., Horse Trail Canyon drainage, alluvium, 5., 500 ft. alt., Welsh 356.

Wyethia scabra Hook.

Steep east-facing sandy slope, Orchard Creek Draw, Curtis formation, 4, 800 ft. alt.., Welsh 297.

Xanthium italicum Morr.

Headquarters area, Bradley 5373. REFERENCES

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1954. Illustrated flora of the Pacific States. Vol. III: Geraniums to Figworts. Stanford University, California: Stanford University Press.

Beath, 0. ,A. 1943. Toxic vegetation growing on the Salt Wash Sand- stone m.em.ber of the Morrison Formation. Am..er. Jour. Bot. 30: 698-707.

Beath, 0. A. J Eppson, H.F .• and Gilbert, C. S. l 93S. Selenium. and other toxic minerals in soils and vegetation. Wyo. Agri. Exp. Sta. Bull. 206.

1937. Selenium in soils and vegetation associated with rocks of Permian and Triassic age .• Am.er. Jour. Bot. 25: 96-101.

1939. The use of indicator plants in location seleniferous areas in the western United States, I. General. Amer. Jour. Bot. 26: 2.57-2.69,

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1940. The use of indicator plants in locating seleniferous areas in the western United States, III. Further studies. Arner. Jour. Bot. 2.7: 564-573.

1941. The use of indicator plants in locating selenµerous areas in th.e western United States, IV. Progress report. Amer. Jour. Bot. 2.8: 887-900.

Bradley, Ruth Ann Wolf. 1950. The vascular flora of Moffat County, Colorado. Unpublished Master's thesis, Department of Biology. University of Colorado.

Byers, H. G. 1935. Selenium occurrence in certain soils in the United States, with a discussion of related topics. U.S. Dept. Agric. Tech. Bull. 482: 47p.

Cannon, Helen L. 1952. The effect of uranium-vanadium deposits on the vegetation of the Colorado plateau.. Arner. Jour. Sci. 250: 735-770.

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Untermann, G. E. l and Untermann1- B .. R. 1954. Geology of the Dinosaur National Monument and vicinity, Utah-Colorado. Utah Geol. Miner. Sur. Bull. 42. ABSTRACT

The Dina-sa.ur N-.ticmal Mol\llDlent is situated Mong the drain.age of the Yampa an,4 Gree;n IUvers in northeastern Ute,h and nortltwestern Colorado. Thia· area cOl'J.8.ists of appl'oxorna.tely ZOO, 000 acres and is cha.ractedzed. by its i-qged appearance and its deep steep ..walled canyons. The ca.nyona are ofte;n over 2. 500 feet dee,. The Utah part of th.e Monument consists of about 75. 008 acre• and e>ccurs partly in the north east se~tion of the Uin~ Ba•in and partly on the south slope of the Uinta Mountains.

The geog~aphic location of the Monument is interesting when the topography of the •urrounding region hs considered. To the south and west of are.a. lies th.e arid lowlands of the Uinta Basln. On each side of the Basin are m0'1Jl.tain ran,.ges which.form the rim of the Basin .. To the south lies the Tav-.pµ.t• Plateau, to the west the Wasatch Moun- tains, to the north the Uin~ Mountains, and to the east are those mountain range.a in Colorado whose ulthnate wester• drainage is the Green River via the White River. The maxim.um r.~lief for the Utah pa~ of the Monument is about Z, 550 feet. The lower elevation is listed as 4, 76.3 feet and the upper elevation on the Y~pa Plateau is 7732. feet. Th~ rainfall in the vicinity 0£ the M~nu.ment is arc>lmd nine inches a year. Most of the 1>:recipitation occurs as rain d.uring the spring and fall months. Sum.mer $torms ar~ sporadic, restricted in size, and are often of a torrential nature. The present topographical features of the area were produced by erosion after the tectonic activity at the end of the Creta~eous and at sub.sequent intervals. Tb.e major erosion.al features are the Split Mountain Gorge, Island and J;tainbow Parlta, and Whirlpool Canyon. To the south of the Green River are the Yampa. and Blue Mountain plateaus. These plateaus are contin~tions of the Jensen and Split Mountain anticlines. The slopes of the Split Mountain have been eroded exposing the older underlying formations. These foxm a sexies of concentric ridges &l"Ound the south., west, and north slopes of the mountain. The geological. eras l."ep-resented range from Paleozoic to Cenezoic. The periods represented range from Cambrian to Qlµ.ternary, but the Devonian, Silurian, and Ordovician are missing. Eighteen formations occur in the Utah pa:rt of the Monument. The geological formations of the Dinosaur National Monument May be divided into shale, sandstone, and alluvium. The plant communities on the sandstone £ormation.s are s hnilar and contain the following important species: JuniP:!rus utahensis (Engelm.) Lemmon (usually dominant), Amelanchier utahensis Koehne, Ephedra viridis Coville, and Cereocarl?us intricatus S. Wats. The major differences between the sandstone formations is the density and relative abundance of the var- iour species. On the shale formations there is a flora that is distinct from th.at on the sandstone formations. Each ,shale £orma.tion supports communities distinct £rom: those on other shale £ormations. The dominant species on the Mancos shale is Atriplex corru1ata. Wats. which forms essentially pure stands on some of the north facing slopes.. On the Mowry shale formation the dominant species are Eriogonum corymbosum Benth. and Eriosonum effusum Nutt. In the Monument these two species are restricted to the Mowry shale ( the Moenkopi formation supports some scattered specimens of !?_. corymbosum Bentb.. but these differ from those on the Mowry in pubescence and growth habit). Tla.ese two species are not associated with one another within the Monument. Eriogonwn corymbosum Ben.th. o-ecupies the Mowry in the southet'n part of the .Monument and !• effusum Nutt. occurs in the Mowry in the northern part of the Monument. The Morrison formation supports two types of vegetation. On the shale parts of the formation the dominant species is Sarcobatus vermiculatus (Hook) Torr. Where sandstone lenses out-erop the dominant vegetation consists of an association of Atri;elex confertifolia (Torr. &: Frem .. ) Wats. and Artem.isia tridentata Nutt. Alluvium in the Monument generally supports Artemisia tridentata and Sarcoba.tus vermieulatus. Along the Green River and smaller -·stream courses occur Populus-Saiix. associations. Some of the sandstone formations sac:h. a.s th.e Curtis, Carmel, Chhtle, and Moenkopi support plants reported to be selenium indicators. The Morrison formation ,urh.ich. consists largely of sh.ale also supports these selenium indica.ters. On these formations two common species of selenium indicator plants are Stanlera pinna.ta (Pursh.) Britton and A!\,tragalus saurinus Barneby. These two species are restricted to the f'ormations listed above. However, A. saurinus Barneby is not found on the Ch.inle formation.. Other species reported to be selenium indicators are AstraeJ.l!s confertiflorus A. Gray from the .Morris.on, ~- th(Jmj)sonae S .• Wats. from the Park City, and!• bisulca.tus (Hood) Gray from alluvium in .Rainbow Park.