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Another Jewel in the Crown: A Report on the Flora of the Sierra De Los Ajos, ,

1 2 3 Mark Fishbein , Richard Felger , and Florentino Garza

Abstract. -We report here on the flora of the Sierra de los Ajos, Sonora, Mexico, based on collections made in 1992 and 1993. The known flora of this range contains 376 species of vascular in 93 families. Based on our collections and the results of floristic studies of other Sky Island ranges, we anticipate that the total flora of the Sierra de los Ajos contains over 1000 species. We have documented the only known occurrences in Mexico of two species that are candidates for listing as threatened or endangered species in the , various new distribution records for Mexico and Sonora, and large range extensions of a number of other plants. This work contributes to a projected flora of the Sky Island region.

INTRODUCTION Islands north of the Mexico-U.S. border is surpris­ ing considering that the floras of and The flora of the Sierra de los Ajos includes sev­ were first produced in the early part of eral notable taxa, including some that are this century (Wooton and Standley 1915, Kearney considered in danger of extinction, some that are and Peebles 1942). In fact, many of the additions far disjunct from the nearest known populations, to the flora of Arizona have come from botanical and some that show a marked extension of their exploration of the Sky Islands (e.g. Lehr and known range. We have documented se~eral state Pinkava 1980, 1982). It is perhaps less surprising and national distribution records in the Ajos. We that the ranges that lie to the south of the interna­ predict that the total flora of the range will exceed tional border have received comparatively less 1000 species, and will contain a highly diverse attention, because of their location on the north­ mixture of biogeographic elements, as is typical of western frontier of Mexico. To date, reasonably regional Sky Island ranges. Because they occur complete floras have been published for only near the center of the Sky Island bioregion, which three of the aproximately two dozen Sky Island includes isolated mountain ranges south of the ranges: the Sierra del Tigre in Sonora (White 1948) and north of the Sierra Madre Occi­ and the Rincon Mountains (Bowers and McLaugh­ dental, the flora of the Sierra de los Ajos provides lin 1987) and Pinaleno Mountains (McLaughlin an important basis for understanding the flora of 1993) in Arizona. The flora of the Huachuca Mou­ the bioregion as a whole. tains in Arizona is in preparation and will soon be The Sierra de los Ajos occur in a botanically submitted for publication (J. Bowers and S. underexplored region of . Despite McLaughlin, personal communication). over 70 years of intensive collecting, the Sky Is­ The Sierra de los Ajos lie just south of the in­ land bioregion remains one of the least well ternational border, which nearly bisects the region known floristic areas of temperate North America. (fig. 1). Like the Sky Island region generally, the The paucity of floristic information about the Sky Ajos occur at the juncture of four major bio­ geographic regions: Madrean, Sonoran, Chihuahuan, and Southern Rockies/Mogollon, in 1Department of Ecology and Evolutionary Biology and Herbarium, University of Arizona, Tucson, AZ. approximate order of their contribution to the 2 Drylands Institute, Tucson, AZ. flora. Streams rising in the Ajos contribute to three 3 Centro Ecologico de Sonora, Apartado Postal No. 1497, Hermosillo, major river systems: the northward-flowing Rio Sonora. San Pedro and the southward-flowing Rio Sonora

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Flgure1.-The Sky Island bloreglon of northwestern Mexico and southwestern United States. Sierra de los Ajos are Indicated by an asterisk (*). and Rio Yaqui. Although several streams have between t~t of the Huachuca Mts. (-1375 m) and perennial stretches, none have perennial flows be­ the Rincon'Mts. (-1725 m) and is an intermediate yond the pediment of the range or reach the major value for the Sky Islands. rivers of the valleys. The prevalent geological formations in the Si­ The low point in the valleys surrounding the erra de los Ajos are volcanic and of Tertiary Ajos occurs at Bacoachi on the Rio Sonora (-1050 origin. An unusual feature of the range, and one m). The highest peak, Cerro de las Flores, rises to that is presumably important to the flora and 2625 m and is the highest point in the state of vegetation, is the large outcrop of limestone Sonora. Thus, the overall relief in the Ajos is ap­ (probably of Cretaceous origin) that forms the proximately 1575 m. This elevational range lies three highest peaks of the range. Following the

127 formation of these rocks, basin and range faulting on south-facing slopes from low- to mid-eleva­ and subsequent erosion created the present-day tions. The common are Quercus emoryi, Q. topography of these mountains. oblongifolia, and Q. arizonica. Common grasses in­ The climate of the Ajos is typical of the region, clude Bouteloua spp., Eragrostis spp., Bothriochloa with bimodal, nearly equally distibuted summer barbinodis, and Aristida spp. Other conspicuous and winter rainfall, interrupted by a hot arid fore­ species include Juniperus deppeana, and Agave cf. summer (Solis-Garza, et a1. 1993). Near desert palmeri. Some level sites in this elevational range conditions prevail at the lowest elevations, are dominated by Juniperus coahuilensis and Yucca whereas the highest peaks experience a much arizonica. cooler and wetter climate due to orthographic Riparian forests change more gradually with processes. Microclimate diversity also contributes elevation than the corrsponding ridge and slope to the floristic diversity Southern exposures that vegetation. At low elevations xeroriparian areas are protected from frost can support species with support a sparse woodland of Celtis reticulata, Chi­ "tropical" affinities, whereas steep north-facing lopsis linearis, and Prosopis velutina. At the foot of canyons with cold air drainage support species the range, Populus fremontii, Platanus wrightii and with northern affinities. velutina form streamway forests. At mid­ elevations in Canon Evans, a diverse riparian assernblage includes Acer grandidentatum, Alnus VEGETATION oblongifolia, Juglans major, Juniperus scopulorum, and Populus fremontii. Abies concolor, Acer gran­ Biotic communities in the Sierra de los Ajos didentatum, and Populus tremuloides occur at the include mixed conifer forest, montane meadows, heads of the major canyons. Riparian communi­ "montane chaparral", pine- forest, oak wood­ ties along one stream in the Ajos are described by land, oak and mesquite grassland, and riparian Solis-Garza and associates (1993). forest. Only a brief discussion of these communi­ ties, which have been discussed in detail elsewhere (e.g. Marshall 1957, Brown 1982), will be presented here. FLORA Mixed conifer forest is of limited extent in the Ajos and is restricted to north-facing slopes at The earliest botanical collections from the Si­ high elevation. Common include Abies con­ erra de los Ajos preserved in herbaria are likely to color, Pinus ponderosa var. arizonica, Pinus be those of George Thurber, botanist with the first strobiformis, and Pseudotsuga menziesii. Montane U.S.-Mexico Boundary Commission. The commis­ meadows occur at sites that would support mixed sion approached the Ajos from the east and conifer, pine, or pine-oak forest in the absence of skirted the eastern and southern flanks of the fire. Because of the fire history of the Ajos (see range in May and June of 1851 on their way to below), these areas now support a diverse assem­ Bacoachi, on the Rio Sonora (Bartlett 1854). blage of herbs and grasses including The first collections from this century that we Blepharoneuron tricholepis, Delphinium tenuisectum, have seen were made by Joe Marshall in 1951. Glandularia bipinnatifida, Koehleria macrantha, Salvia Marshall collected extensively in Canon Evans, a lemmoni, Silene laciniata, and Viguiera multiflora. very large, north and west trending canyon that "Montane chaparral" occurs at high elevations on contains the largest perennial stream in the range. exposed limestone ridges, including the tops of Marshall was the first to document a distinct Ma­ the highest peaks. Common species in this asso­ drean pine-oak forest that extends north through ciation include Cercocarpus brevifolius, Eriogonum the Sky Islands in his classic publication on birds jamesii, Holodiscus dumosus, and Quercus gambelii. of the pine-oak woodland (Marshall 1957). Pine-oak forest is the most wide spread forest We are aware of four collections from the Si­ type in the Ajos and is predominant at mid-eleva­ erra de los Ajos from the 1980's and early 1990's. tions. Common trees and shrubs include Arbutus In September 1982, Frank Reichenbacher made an arizonica, Arctostaphylos pungens, Ceanothus depres­ extensive collection in Canon Evans. Paul Martin sus, Garrya wrightii, Juniperus deppeana, Pinus and associates made small collections in Jul y 1983 engelmannii, P. ponderosa var. arizonica, Quercus ari­ and April 1991, also in Canon Evans. Peter Warren zonica, Q. emoryi, Q. hypoleucoides, and Rhus and Esther Saucedo surveyed this canyon for rare trilobata. Oak woodland and grassland occur on plants in 1989. Prior to our efforts, most collecting north-facing slopes at the lowest elevations and in the range has occurred in Canon Evans.

128 Thus far we have made two extensive collect­ Table 1.-Notable Collections in the Sierra de los Ajos. ing trips in the Sierra de los Ajos totaling ten Species (Family) Significance person-days of fieldwork. In October 1992 we sur­ marginata () New record for Sonora Arenaria stricta (Caryophyllaceae) New record for Sonora, veyed the grassland on the north side of the new record for Sky Islands, range, the lower reaches of Canon Evans, a tran­ range extension from western sect leading up the north side of the range (along an old roadway), the heads of the major east- and nyctaginifolia (Asclepiadaceae) New record for Sonora west-trending streams (Arroyo Frijolito and Hoya Botrychium virginianum del Packard, respectively), the saddle between the (Op h ioglossaceae) Only extant Sky Island highest peaks of the range, and the north slope population (see text) eaton;; (Adiantaceae) New record for Sonora? and top of the highest peak (Cerro de las Flores). Desmanthus cooleyi (Fabaceae) New record for Sonora In July 1993 we surveyed in the southern portion Euphorbia melanadenia () New record for Sonora of the range, mostly in the vicinity of Arroyo La pilosum () New record for Mexico, Cieneguita and the southern crest of the range, as range extension from Pinaleno well as the pass between the Ajos and the Sierra Mts. Buenos Aires. Our collections are thus biased to­ Ulium parryi (Liliaceae) New record for Mexico orthoneurus wards the summer flora and we expect that () New record for Mexico further additions to the flora will contain many Smilacina racemOSE! cool-season ephemeral and spring-flowering per­ (Convallariaceae) New record for Mexico? Smilacina stellata (Convallariaceae) New record for Mexico? ennial species. Thermopsis montana (Fabaceae) New record for Mexico? To date we have documented 376 species of Tinantia erecta (Commelinaceae) New record for Sonora, new record for Sky Islands, vascular plants in 246 genera and 93 families (Ap­ range extension from south­ pendix 1). Our records are based primarily on our western Chihuahua collections, the first set of which is deposited at Irifu.li.u.m wormskioldij (Fabaceae) New record for Mexico? the University of Arizona Herbarium (ARIZ); a second set is deposited at the herbarium at the the southwest extension of the range of Arenaria Instituto de Biologia, UNAM (MEXU), and addi­ stricta ssp, texana from west Texas and the north­ tional duplicates are deposited elsewhere. Some west extension of Tinantia erecta from records are based on other collections at ARIZ, on southwestern Chihuahua. our photo vouchers, and on undocumented obser­ In a sense, the Sierra de los Ajos and vations. The five families that contribute the most Huachuca Mountains can be thought of as "sister to the known flora are Asteraceae (62 .. species), ranges" because of their close proximity and simi­ Poaceae (49), Fabaceae (33), Lamiaceae (9), and lar geology and elevational range. Because the Scrophulariaceae (9). These families account for Huachucas have a well-documented flora (J. Bow­ 43% of the specific and intraspecific taxa in the ers and S. McLaughlin, in preparation), it is known flora. The nine largest genera in the flora interesting to note which taxa occur in the Ajos are Muhlenbergia (Poaceae, 9 species), Asclepias but not in the Huachucas. We have documented (Asclepiadaceae, 8), Quercus (, 8), Aristida 20 such taxa (Table 2). Most of these taxa are Ma­ (Poaceae, 5), Bouteloua (Poaceae, 5), (As­ drean species that reach their northern limit in the teraceae, 5), (Asteraceae, 5), Pinus Sierra de los Ajos (e.g. Ratibida mexicana, Quer­ (Pinaceae, 5), and Senecio (Asteraceae, 5). cus mcvaughii, Q. viminea, Tinantia erecta). One of the significant results of our surveys is Some, however, are species apparently restricted the documentation of previously unknown popu­ to very mesic or high elevation habitats (Le. Alnus lations of species being considered for listing as oblongifolia, Botrychium virea maculata, Galer­ endangered or threatened in the United States, orum, and Thermopsis moning that these p~ual new records for Mexico and Sonora, and exten­ populationse Ajos, but not tsidering that the sions of the known ranges of various species Huachucas occur further north and rise to an ele­ (Table 1). We located new populations of Lilium vation 270 m higher than the Ajos. Botrychium parryi (Liliaceae) and Rumex orthoneurus (Poly­ virginianum was known elsewhere in the region gonaceae), both Category 1 candidates for listing only from the Santa Rita Mountains, where it has as federally endangered or threatened species by not been seen for about 100 years and is presumed the United States Fish and Wildlife Service, and extirpated. Callum pilosum is otherwise known in both previously unknown in Mexico (Felger and the region only from two collections from the Pi­ Fishbein 1993, Fishbein and Felger 1993). Two of naleflq'Mountains. Juniperus scopulorum is the more surprising collections from the Ajos are unknown elsewhere in the region,

129 The proportion of non-native species in the lar ranges in the United States, there is a relative flora is remarkly low (14 species, or 3.7% of the lacknce in the form ito los Ajos. The Ajos have total flora). This low figure may reflect sampling been cited as an example of an area that has expe­ bias (e.g. if the spring flora has disproportionately rienced natural fire regimes in the period since more non-natives) or an actual deficit of intro­ European colonization (Swetnam 1988). The duced species. If this pattern is supported by Huachuca Mountains, which have arguably expe­ further collections, it certainly merits future inves­ rienced more catastrophic fires in the last two tigations into the cause of the resistance of the decades because of a history of fire suppression, Sierra de los Ajos to non-native invasions. make ari interesting comparison to the Sierra de McLaughlin's (1993) analysis of the relation­ los Ajos. Such a comparison would be a valuable ship of elevational range and native species first step in generating hypotheses about the ef­ richness in the southwestern United States would fects of bum suppression on floras. predict about 600 species for the Sierra de los Mining seems to have been of limited scope in Ajos, based on elevational range alone. Although the Sierra de los Ajos. Although there are no cur­ the known flora of the Pinaleno Mountains is rently active mines, the geology of the range and well-predicted by this relationship, other Sky Is­ the proximity to the large mines at Cananea sug­ lands (Le. the Rincon Mountains and the gest potential mineral exploitation in the future. Huachuca Mountains) greatly exceed their pre­ Current human uses of the Sierra de los Ajos dicted values, by 50% in the case of the Rincons center on cattle ranching. The lower elevations are and 90% in the case of the Huachucas. Based on readily accessible to cattle and are utilized as ran­ these values, the flora of the Ajos should contain gelands. The steepest high-elevation canyons and 900-1100 species. some lower elevation cliffs are inaccessible to live­ stock. In 1993, some riparian areas on the south side of the range showed evidence of the cumula­ HUMAN INFLUENCES AND FUTURE tive impacts of intensive grazing. Overgrazed PROSPECTS clumps of grass were very sparse and large stands of weedy native (e.g. Croton texensis) and non-na­ A major factor influencing the vegetation of tive (e.g. Nicotiana glauca) species formed dense the Sierra de los Ajos has been frequent fires. Es­ and extensive patches. pecially in the last century, fires have dramatically The Sierra de los Ajos has been included in a altered the appearance and composition of vege­ system of state level ecological preserves in the tation (M. Fishbein, personal observation; SANPES program. Although it was formerly man­ Swetnam 1988). This is particulary evident in the aged by the federal forestry agency (SARH), high country, which is covered by meadows and management of many preserves in the SANPES 1/chaparral" rather than forest. Compared to simi- program are administered by the Centro Ecologico de Sonora. The Ajos were originally in­ Table 2.-Natlve taxa known from the Sierra de cluded among these, but their mangement has los Ajos that are unknown from the Huachuca Mountains. now reverted to SARH. Species (Family) Agastache pal/ida (Lamiaceae) Alnus oblongifolia (Betulaceae) Arenaria stricta (Caryophyllaceae) ACKNOWLEDGEMENTS Botrychium virginianum (Ophioglossaceae) Chimaphila maculata (Ericaceae) We gratefully acknowledge the contributions alpina () and comradeship of our friends and eagle-eyed Galium pilosum (Rubiaceae) Gutie"ezia alamanii (Asteraceae) collectors George Ferguson, Martin Haro, Jim Hoffmanseggia glauca (Fabaceae) Malusa, Donya Meggs, Sean Sartorius, and Dale Juniperus scopulorum (Cupressaceae) Turner. We also thank Lucinda McDade and the Lopezia gracilis (Onagraceae) Penstemon campanulatus (Scrophulariaceae) staff at the University of Arizona Herbarium for Phlox nana (Polemoniaceae) their assistance. Charlotte and John Reeder gra­ Quercus mcvaughii (Fagaceae) ciously identified or verified our Poaceae. Shelley Quercus viminea (Fagaceae) Ratibida mexicana (Asteraceae) McMahon made valuable comments that im­ Seymeria bipinnatisecta (Scrophulariaceae) proved this paper. This work was supported in Thermopsis montana (Fabaceae) part by a grant from the Wallace Genetic Founda­ Tinantia erecta (Commelinaceae) Yucca arizonica (Agavaceae) tion to Richard Felger.

130 ).

LITERATURE CITED Lehr,J.H.and D.J.Pinkava.1982.Acatalogueofthe flora of Arizona. Supplement II.Journal of the Arizona- Bartlett, J.R. 1854. Personal Narrative of Explorations and Academy of Science 17:19-26. Incidents in Texas, New Mexico, , Sonora, Marshall, J .T. 1957. Birds of the Pine-Oak Woodland in and Chihuahua, Connected with the United States and Southern Arizona and Adjacent Mexico. Pacific Coast Mexican Boundary Commission, During the Years Avifauna, No. 32. 1850, '51, '52, and '53, vol. 1, : Appleton and McLaughlin, S.P. 1993. Additions to the flora of the Pi­ Co. naleno Mountains, Arizona. Journal of the Bowers, J.E. and S.P. McLaughlin. 1987. Flora and vegeta­ Arizona-Nevada Academy of Science 27:5-32. tion of the Rincon Mountains, Pima County, Arizona. Solis-Garza, G., W. Brady, and A. Medina. 1993. Riparian Desert Plants 8:51-94. plant communities on the the Rio los Ajos, Sonora, Brown, D.E. (ed.) 1982. Biotic communities of the American Mexico. Ecologica 3: 13-22. Southwest-United States and Mexico. Desert Plants Swetnam, T.W. 1988. Fire history and climate in the south­ 4:3-341. western United States. In Krammes (ed.), Effects of Fire Felger, R.S. and M. Fishbein. 1993 . Noteworthy Collections. In Management of Southwestern Natural Resources, Mexico. Madrono 40:270-1. USDA Forest Service General Technical Report RM -191, Fishbein, M. and R.5. Felger. 1993 . Noteworthy Collections. pp.6-17. Mexico. Madrono 40:271. White, S.5.1948. The vegetation of flora of the region of the Kearney, T.H. and R.H. Peebles. 1942. Flowering Plants and Rio de Bavispe in northeastern Sonora, Mexico. Lloydia of Arizona. U.S. Department of Agriculture Mis­ 11:229-302. cellaneousPublicationNo.423. Wooton, E.O. and P.C. Standley. 1915. Flora of New Mexico. Lehr,J.H.and D.J.Pinkava.1980.Acatalogueofthe flora of Contributions from the United States National Herbar­ Arizona. Supplement I. Journal of the Arizona-Nevada ium, vol. 19. Academy of Science 15:17-32.

Appendix 1. Checklist of the Flora of the Sierra de los Ajos, Sonora, Mexico. Records are based primarily on specimens collected by the authors and associates, 1992-1993. A few records are based on other collections, photo VOUChers, or observations. Non-native and apparently self-reproducing species are indicated by an asterisk (*).

Acanthaceae Toxicodendron radicans Kuntze var. divaricatum Antennaria marginata Greene Dyschoriste decumbens (A. Gray) Kuntz (Green\?) Barkley Arlemesia dracuncillus L. Arlemesia ludoviciana Nuttall Var' mexicana (Willd- Aceraceae Apiaceae enowex Sprengel) Fernald Acer grandidentatum Nuttall Eryngium heterophyllum Engelmann Aster potosinus A. Gray Eryngium lemmoni Coulter & Rose salicifolia (Ruiz & Pavon) Persoon Adiantaceae Ligusticum porteri Coulter & Rose Baccharis thesioides H.B.K. limitanea (Maxon) Windham var. Pseudocymopterus montanus (A. Gray) Coulter & Baccharis d. pteronioides DC. mexicana (Maxon) Windham Rose Bahia dissecta (A. Gray) Britton Bommeria hispida (Kuhn) Underwood Bidens aurea (Aiton) Sherff Cheilanthes bonariensis (Willdenow) Proctor Cheilanthes eatoni Baker Macrosiphonia brachysiphon (Torrey) A. Gray Bidens bigelovij A. Gray Cheilanthes wrightii Hooker Brickellia betonicaefolia A. Gray Pellaea atropurpurea (L.) Link Araliaceae Brickellia eupatorioides (L.) Shinners var. chlo- Aralia racemosa L. rolepis (Wooton & Standley) B. Turner Agavaceae Brickellia grandiflora (Hooker) Nuttall Agave d. palmeri Englemann Asdepiadaceae Brickellia rusbyi A. Gray Agave parry; Engelmann var. huachucensis Asclepias asperula (Decaisne) Woodson ssp. aspe- Brickellia simplex A. Gray (Baker) little ex L.D. Benson rula Centaurea rothrockii Greenman Yucca arizonica McKelvey Asclepias elata Bentham Cirsium sp. 1 Yucca schottii Engelmann Asclepias hypoleuca (A. Gray) Woodson Cirsium sp. 2 Asclepias lemmoni A. Gray Conyza canadensis (L.) Cronquist Alliaceae Asclepias nummularia Torrey parviflorus Gacquin) HB.K. Allium plummerae S. Watson Asclepias nyctaginifolia A. Gray Erigeron arisolius Nesom Asclepias subverticillata (A. Gray) Vail Erigeron arizonicus A. Gray Amaranthaceae Asclepias tuberosa L. ssp. interior Woodson A. Gray Alternanthera repens (L.) Kuntze? Erigeron d. flagellaris Amaranthus graecizans L. Aspleniaceae Erigeron neomexicanus A. Gray Amaranthus d. palmeri S. Watson Asplenium resiliens Kunze Erigeron platyphyllus Greene Galinsoga parviflora Cavanilles Anacardiaceae Asteraceae Gnaphalium macounii Greene Rhus trilobata Nuttall herbacea (A. Gray) King & Robinson Guardiola platyphylla A. Gray Rhus choriophylla Wooton & Standley Ageratina rothrockii (A. Gray) King & Robinson Gutierrez;a alamanij A. Gray var. megalocephala Rhus glabra L. Ambrosia psilostachya DC. (Fernald) M.A. Lane

131 Gutierrezia wrightii A. Gray Caryophyllaceae Fabaceae Gymnosperma glutinosum (Sprengel) Lessing Arenaria lanuginosa (Michaux) Rohrbach ssp. Acacia angustissima (Mill.) Kuntze Helianthus petiolaris Nuttall saxosa (A. Gray) Maguire Amorpha fruticosa L. Heterotheca sulxzxillaris (Lamarck) Britton & Arenaria strida Michaux ssp. texana (Robinson) Astragalus nothoxys A. Gray Rusby Maguire Calliandra eriophylla Bentham Hieracium crepidispermum Fries Dnj1naria leptophylla (Chamisso & Schlechtendal) Chamaecrista serpens (L.) Greene var. wrightii (A. Hieracium fendleri Schultz-Bipontinus Rohrb. var. nodosa (Engelmann) J. Duke Gray) Irwin & Barneby Hymenoclea sp. Silene laciniata Cavanilles var. greggii A. Gray Cologania angustifolia HB.K. wrightii A. Gray Cologania obovata Schlechtendahl Laduca graminifolia Michaux Chenopodiaceae Coursetia caribea Oacquin) Lavin var. sericea (A. Leibnitzia seemannii (Schultz-Bipontinus) Nesom Chenopodium incisum Poiret Gray) Lavin Machaeranthera sp. 1 '" Salsola kali L. Dalea d. candida (Michaux) Willdenow Machaeranthera sp. 2 Dalea filiform is A. Gray longicorne A. Gray Cochlospermaceae Dalea versicolor Zuccarini var. sessilis (A. Gray) Psilactis gentry; (Standley) Morgan Amoreuxia palmatifida M09no & Sesse Barneby Ratibida mexicana (S. Watson) Sharp Desmanthus cooleyi (Eaton) Trelease Senecio carlomasonii B. Turner & T. Barkley Commelinaceae Desmodium grahami A. Gray Senecio flaccidus Lessing var. douglasii (DC) B. Commelina dianthifolia Delile Erythrina flabelliformis Kearney Turner & T. Barkley Tinantia erecta Oacquin) Schlechtendal Eysenhardtia orlhocarpa (A. Gray) S. Watson var. Senecio neomexicanus A. Gray orthocarpa Senecio parryi A. Gray Convallariaceae Galadia wright;; A. Gray Senecio wootoni Greene Smilacina racemosa (L.) Desfontaines Hoffmanseggia glauca (Ortega) Eifert Solidago scabrida DC Smilacina stellata (L.) Desfontaines Lathyrus lanzwerlii Kellog var. leucanthus Solidago wrightii A. Gray var. adenophora Blake (Rydberg) Dom Stevia serrata Cavanilles var. serrata Convolvulaceae Lotus oroooides (HB.K) Ottley Tagetes lemmoni A. Gray Convolvulus equitans Bentham Lupinus huachucanus Jones Thelesperma megapotamicum (Sprengel) Kuntze Evolvulus ariwnicus A. Gray Lupinus sp. Verbesina longifolia A. Gray Ipomoea longifolia Bentham '" Medicago sativa L. Viguiera annua Oones) Blake Ipomoea thurberi A. Gray Mimosa d. aculeaticarpa Ortega Viquiera multiflora (Nuttall) Blake var. multiflora Mimosa dysocarpa Bentham Xanthium strumarium L. Crassulaceae Mimosa grahamii A. Gray var. grahamii Zinnia peruviana L. Sedum stelliforme S. Watson Phaseolus sp. Prosopis cf. velutina Wooton Betulaceae Cucurbitaceae Rhyncosia senna Gilles ex Hooker var. texana (Tor- Alnus oblongifolia Torrey Apodanthera undulata A. Gray rey & Gray) M.C Johnston Cucurbita foetidissima HB.K. Robinia neomexicana A. Gray var. neomexicana Bignoniaceae Tephrosia thurberi (Rydberg) CE. Wood Chilopsis linearis (Cavanilles) Sweet ssp. a1'Cuata Cupressaceae Thermopsis montana Nuttall var. montana (Fosberg) Henrickson Juniperus deppeana Steudel Trifolium wormskioldii Lehm. var. longicaule (Woo- Juniperus coahuilensis (Martinez) Gaussen ex R.P. ton & Standley) L. Benson. Boraginaceae Adams Vicia pulchella H.B.K. Lithospermum cobrense Greene Juniperus scopulorum Sargent Macromeria viridiflora DC Fagaceae Cyperaceae Quercus ariwnica Sargent Brassicaceae Cyperus d. hermaphroditis Oacquin) Standley Quercus emoryi Torrey Draba petrophila Greene var. viridis (Heller) CL. Cyperus d. pringlei Britton Quercus gambelii Nuttall Hitchcock Cyperus rushyi Britton Quercus hypoleucoides Camus Erysimum capitatum (Douglas) Greene Eleocharis montevidensis Kunth Quercus mcvaughii Spellenberg Lepidium thurberi Wooton Quercus oblongifolia Torrey "'Rorippa nasturtium-aquaticum (L.) Hayek Dennstaed tiaceae Quercus rugosa Nee Schoenecrambe linearifolia (A. Gray) Rollins Pteridium aquilinum (L.) Kuhn var'l'ubescens Un­ Quercus viminea Trelease Thlaspi montanum L. var. montanum derwood Fouq uieriaceae Cadaceae Dryopteridaceae Fouquieria splendens Engelmann ssp. splendens Coryphantha recurvata (Engelmann) Britton & Cystopteris fragilis (L.) Bernh. Rose Woodsia cochisensis Windham Garryaceae Echinocereus d. coccineus Engelmann Garrya wrightii Torrey Echinocereus rigidissimus Rose Equisetaceae Opuntia d. engelmannii Salm-Dyck Equisetum sp. Gentianaceae Opuntia spinosiol' (Engelmann & Bigelow) Gentianella microcalyx (Lemmon) J.M. Gillett Tourney Ericaceae Opuntia d. versicolor Engelmann Arbutus ariwnica (A. Gray) Sargent Geraniaceae Arctostaphylos pungens HB.K. Geranium caespitosum James Campanulaceae Chimaphila maculata (L.) Pursh Geranium richardsonii Fischer & Trautvetter Lobelia anatina Wimmer Monotropa hypopitys L. Hydrangeaceae Caparaceae Euphorbiaceae Philadelphus microphyllus A. Gray Polanisia dodecandra (L.) DC. Acalypha lindheimeri Miiller-Argoviensis angustidens Torrey Hydrophyllaceae Caprifoliaceae Croton texensis (Klotsch) Miiller-Argoviensis Phacel;a heterophylla Pursh Lonicera sp. Euplwrbia alta Norton Sambucus sp. Euphorbia melanadenia Torrey Iridaceae Symphoricarpos oreophilus A. Gray var. oreophilus Euphorbia pediculifera Engelmann var. pediculifera Iris missouriensis Nuttall macrorhiza Bentham Nemastylis tenuis (Herbert) Baker Tragia laciniata (Torrey) Miiller-Argoviensis Sisyrinchium scabrum Schlechtendahl & Chamisso

132 Juglandaceae Orobanchacea. Muhlenbergia pauciflof'tl Buckley }uglans major (forrey) Heller Conopholis alpitUJ Uebmann Val. ",exa"" (A­ Muhlenbergia tepens (Presl) A.S. Hitchcock Gray ex S. Watson) Haynes Muhlenbergia rigida (HB.K) Trinius Juncaceae Muhlenbergia sinuosa Swallen }uncu.s ensifolius Wikstrom var. brunnescens Oxalidaceae Muhlenbergia trifida Hackel (Rydberg) Cronquist Oxalis a. albieans Kunth ssp. piloSll (Nuttall) Eiten Muhlenbe1Jia wolfii (Vasey) Rydberg }uncu.s tenuis Willdenow Oxalis alpitUJ (Rose) Kunth Panicum bulbosum HB.K. Paspalum distiehum L. Lamiaceae Papaveracea. Piptocl.etium fimbriatum (HB.K) A.S. Hitchcock Agastache pallida (lindley) Cory var. pallida A'Jemone pleiacantJ. Greene Piptocl.etium pringlei (Beal) L. Parodi Hedeomasp. "'Polypogon viridis (Gouan) Breistroffer . '" Marrubium vulgare L. Passifloracea. "'Rhynchelytrum repens (Willdenow) CE. Hub- Monarda citriodora Cervantes ex Lagasca ssp. aus- Passiflof'tl mexica"" Jussieu bard tromontana (Epling) Scora Setaria grisebachii Fournier Salvia a. arizoniea A. Gray Phytolaccacea. • So'Jhum halapense (L.) Persoon Salvia lemmoni A. Gray Rivina humilis L. Sporobolus d. airoides Torrey Salvia reflexa Homemann Staehys coccinea Jacquin Pinaceae Polemoniaceae Triehostema ariwnieum A. Gray Abies concolor (Gordon & Glendinning) Hoopes lpomopsis macombii (forrey) V. Grant Pinus cembroides Zuccarini Phlox nana Nutall var. glabella (A. Gray) Brand Liliaceae Pinus engelmannii Carriere Lilium parry; S. Watson Pinus leiophylla Schiede & Deppe var. chihua­ Polygalaceae huana (Engelmann) Shaw Polygala obscura Bentham Linaceae Pinus ponderosa Lawson vu arizonicus (Engel- Linum lewisii Pursh mann) Shaw Polygonaceae Linum puberulum (Engelmann) Heller Pinus strobiformis Engelm. Eriogonum jamesi; Bentham var. undululam (Ben- '" Pinus sylvestris L. tham)Stokes Loasaceae Pseudotsuga menziesii (Milbel) Franoo Eriogonum wrighti; Torrey Mentzelia sp. Polygonum sp. Plantaginacea. '" Rumex crispus L. Lythraceae "'Plantago major L. Rumex orthoneurus Rechinger Lythrum ealifornicum Torrey & Gray Plantago patagoniea Jacquin Portulacaceae Malpighiaceae Platanace.e TaUnum marginatum Greene Aspiearpa hirtella L.C Richard Platanus wrightii S. Watson Potamogetonaceae Malvaceae Poaceae Potamogelon sp. Gossypium thurberi Todaro Aegopogon tenellus (Cavavilles) 1linius Sphaeralcea angustifolia (Cavanilles) G. Don Aristida adscensionis L. Primulaceae Aristida arizona Vasey Samolus vagans Greene Melanthiaceae Aristida divaricata Humboldt & 80npland Zigadenus virescens (HB.K) Macbride Ranunculaceae Aristida ternipes Cavanilles Val. '-muloSll (Hen- rard)1Tent Aquilegia chrysantha A. Gray Nolinaceae Clematis sp. Aristida ternipes Cavanilles Val. temipes Dasylirion wheeleri S. Watson "'Avena d. fahul L. Delphinium andesicola Ewan Nolina microcarpa S. Watson Blepharoneuron tricholepis (Nash) Torrey Delphinium tenuisecta Greene Bothriochloa barbinodis (Lagasca) Herter Thalictrum fendleri A. Gray Nyctaginaceae Bouteloua aristidoides (HB.K.) Grisebach Allionia incarnata L. Bouteloua curtipenduLz (Michaux) Torrey Rhamnaceae Bouteloua grttcilis (HB.K.) Lagasca ex Steudel Ceanothus depressus Bentham Bouteloua hirsuta Lagasca Condalia carrelii M.C Johnston Fraxinus gooddingii little Bouteloua nzdico. (Fournier) Griffths Rhamnus betulaefolia Greene Fraxinus pappilosa linge1sheim Bromus anomalus Rupr. ex Fomnier Fraxinus velutina Torrey Bromus ciliatus L. Rosaceae Chloris virgata Swartz Agrimonia striata Michaux Onagraceae "'Cynodon dactylon (L.) Persoon Cercocarpus brevifolius A. Gray var. brevifolius Epilobium canum (Greene) Raven "'Digitaria sanguitUJlis (L.) Scopoll Holodiscus dumosus (Nuttall) Heller var. australis Epilobium ciliatum Rafinesque ssp. eiliatum Echinochloa crusgalli (L.) Beauvois (Heller) Ley Caura sp. Elymus arizonicus (Scribner" Smith) Gould PotentilLz thurberi A. Gray var. atrorubens Lopezia gracilis S. Watson Elymus elymoides (Rafinesque) Swezey (Rydberg) Kearney & Peebles Oenothera elata HB.K. ssp. hirsutissima (A. Gray) Ef'tIgrostis intermedia A.S. Hitchcock Prunus serotina Ehrhart ssp. virens (Wooton & Dietrich Ef'tIgrostis mexana (Homemann) link vu ",exi­ Standley) McVaugh var. rufula (Wooton & Oenothera laciniata Hill var. pubescens (Willde­ eatUJ Standley) McVaugh now)Munz Ef'tIgrostis pectintlCietl (Michaux) Nee! Val. ",iser­ Prunus serotina Ehrhart ssp. virens (Wooton & rima (Fournier)]. Reeder Standley) MeVaugh var. virens Orchidaceae Eragrostis pectinacea (Michaux) Nee! Val. pecti­ Hexalectris sp. nacea Rubiaceae Malaxis carymbosa (S. Watson) Kuntze Eriochloa acumitUJta (Pres!) Kunth Vilr. minor R.B. Bouvardia ternifolia (Cavanilles) Schlechtendal Malaxis ehrenbergii (Reichenbach) Kuntze Shaw Galium mexicanum Kunth ssp. asperrimum (A. Malaxis macrostachya (Lexarza) Kuntze Heteropogon conlortus (L.) Beauvois Gray) Dempster Platanthera limosa lindley Koehleria nUlCTant'- (Ledeb.) Schult.. Galium pilosum Aiton Leptochloa viscida (Scribner) Beal Calium wrighti; A. Gray Ophioglossaceae Lycurus selosus (Nuttall) C. Reeder wrightii A. Gray Botrychium virginianum (L.) Swartz Muhlenbergia IongiliguLz A.S. Hitchcock MuhlenbelJia m;nutissi",a (Steudel) SwaDen Rutaceae Muhlenbergia monfltna (Nuttall) A.S. Hitchmck Ptelat angustifolia Bentham

133 Penstemon hIlWatus (Cavanilles) Roth ssp. torrey; Valeriana arizonica A. Gray Populus fremontii S. Watson ssp. fremontii (Bentham) Keck Valeriana edulis Nuttall Populus tremuloides Michaux Penstemon campanulatus (Cavanilles) Willdenow Valeriana sorbifolia H.B.K. Salix bonplandiana H.B.K. ssp. chihuahuensis Straw Penstemon stenophyllus A. Gray Vemenaceae Sapindaceae Seymeria bipinnatisecta Seemann Glandularia bipinnatifida (Nuttall) Nuttall Vftr. bip­ Dodonea viscosa L. innatifida Solanaceae \krbena carolina L. Regel Saxifragaceae Datura wrightii ·Nicotianaglauca Graham Violaceae Heuchera sanguinea Engelmann Physalis sp. Viola canadensis L. Solanum eleagnifolium Cavanilles Viscaceae Scrophulariaceae Solanum d. rostratum PhorrJdendron coryae Trelease Castilleja austromontana Standley & Blumer Solanum sp. Vitaceae Castilleja patriotica Fernald Vitis arizonica Engelmann Castilleja tenuiflora Bentham Ulmaceae Mimulus d. cardinalis Douglas Celtis reticulata Torrey Zygophyllaceae Mimulus guttatus DC. Valerianaceae Kalstroemia grandiflora Torrey

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