Mojave Desert Monsoonal Bloom in September 2012

Introduction and Overview
Additional Observations From Our Trip
Checklist of Species Observed, with Species in Bloom Noted

Introduction and Overview

The summer monsoon was quite vigorous in 2012, with thunderstorms in and near the San Jacinto Mountains in Riverside County for a period of two months from mid-July to mid-September. The National Weather Service predicted a chance of rain in Idyllwild on 11-14, 18, 23, 30 and 31 July; 1-23, 28-31 August; and 1-11 September. Radar showed extensive thunderstorm areas in the desert areas to the east during those dates, as well as on additional dates when the monsoon had moved east of the San Jacinto Mountains.

We anticipated that all this rainfall would cause good monsoonal annual blooms, and we were ecstatic when Michael Charters informed Tom of this report from Jim Andre on 10 September 2012:

The entire Mojave National Preserve is aflush with the best overall bloom I've ever seen. You can't miss. The NY Mtns are most fabulous because of the diversity...but one minor caution - roads might be washed out in places because of all the rain. I haven't had too much problems with a 4WD.

Tom immediately made plans to go see this bloom. Due to schedule constraints for some of the participants and reports of essentially all roads in the New York Mountains being closed, we planned a trip for the weekend of 22-23 September. This seemed a good compromise between waiting for roads to be reopened and the fading of the annual bloom due to the summer heat.

That trip was done by Tom Chester, Kate Harper, RT and Shaun Hawke, Anne Kelly and Aaron Schusteff. We botanized from Whitewater Canyon near Palm Springs to the New York Mountains, transecting the Mojave Desert from south to north through 29 Palms, the Sheep Hole Mountains, the Granite / Marble Mountains pass, Kelso, Cima and Ivanpah. See Overview map of route (red line) with elevation profile (profile begins in the south at 29 Palms). In the New York Mountains, we stopped three times along the Ivanpah / New York Mountain Road, beginning at the end of the pavement to Keystone Canyon at 4000 feet elevation, with other stops at 4200 and 4500 feet, and then botanized in Keystone Canyon from 5300 feet to 5500 feet elevation.

That trip was fabulous! We found a total of 111 species in bloom, a number that essentially matches full bloom in the spring in a good year. We saw a total of 171 species on that trip, many of which we had never seen before in California since the New York Mountains has a lot of species that don't grow elsewhere in southern California.

Road conditions were excellent. The Ivanpah / New York Mountain road was in great shape up to Keystone Canyon; a Toyota Prius could have driven it. The Keystone Canyon Road is only driveable for the first two miles, up to the first wash. Those two miles are a bit rough, but my old 1983 Honda Civic Station Wagon could have driven it; only decent clearance is needed.

Fig. 1 shows a map of the area, summarizing roughly the richness of the bloom along our route:

Figure 1. Map Showing Richness of the 2012 Monsoonal Bloom.

Fig. 1. Map Showing Richness of the 2012 Monsoonal Bloom. The red (bone dry), yellow (sparse plants in bloom) and green (rich with plants in bloom) contours roughly indicate the richness of the bloom that we saw from the car in driving along the route covered with dense blue diamonds from our GPS track. Species seen in bloom were numbered along our botanizing route, with only the first occurrence of bloom from each species noted. The labels at various spots in the map indicate which species were found in bloom, with the species identified by number in Table 1 below. The green contour at upper left, surrounding the Teutonia Peak area, is from a report by John Marquis from 12 September 2012, who also provided input for some of the other contours.

Jane Strong researched the rainfall for the Mojave Preserve, and found the biggest event occurred on 21-22 August 2012, which was large enough to get a Rainfall and Flood Event Report. Rainfall totals from that event are given here, and are plotted on top of the Figure 1 map here. Over FOUR INCHES OF RAIN fell in the New York Mountains area over a period of 24 hours!

Our observations clearly confirm this rainfall pattern. We found only 7 species in bloom from 29 Palms to Amboy; an additional 16 species in bloom at Granite Pass, for a total of 23 species in bloom up to Kelso. In contrast, we found another 86 species in bloom in the New York Mountain area, including at Cima! Of course, there are many more species in the New York Mountains due to its diverse range in habitats and elevation. But without rain, few of them would be in bloom.

Since it was very clear that the New York Mountains were the place to be, as advertised by Jim Andre, RT and Shaun returned to that area on the next weekend, accompanied by Pam MacKay and Tim Thomas, making some of the same stops along the Ivanpah / New York Mountain Road, and then spending most of their trip in Caruthers Canyon. On that trip, they saw an additional 23 species in bloom, making a total of 134 species in bloom seen over two weekends. They saw an additional 46 species on that trip, making a total of 217 species seen in the two weekends.

The list of all observed species, along with those observed in bloom, is given in Table 1 below.

Many of the species we saw on our trip were photographed by Michael Charters in 2003 and 2004 on trips led by Jim Andre, and in 2009 on a trip led by Jim Andre and Tasha La Doux; see Michael's pages for his beautiful pictures. Jim Andre and Tasha La Doux regularly lead two day trips in September with the great name of Legends of the Fall: exploring the clandestine flora of early fall in the eastern Mojave Desert.

Our trip was made immensely richer by the plant checklist for the entire Mojave Preserve made by Jim Andre in 2006. With that list in hand, and the Jepson Desert Manual, we were able to identify the vast majority of species that we saw. We deeply appreciate all the work that Jim Andre did to create that list, and to the National Park Service for putting it online.

Our list of observed species in Table 1 derives almost exclusively from Andre's checklist. We found only three species not in his checklist: Opuntia parishii = Grusonia parishii; Solidago velutina; and Zea mays. The first two were undoubtedly just inadvertently omitted from the 2006 checklist, since there are vouchers in the Mojave Preserve of them. In fact, we didn't recognize the Grusonia parishii in the field, thinking it was just a very weird Echinocereus engelmannii that possibly was infected by some virus. (:-) Jim gave us the correct determination, for which we were quite grateful, since none of us had ever seen that species before.

We were very surprised to see cultivated corn, Zea mays, not only thriving but in bloom in several places along our trip, all close to the railroad line that parallels the road from Kelso to Cima. We suspect these are just waifs from seed from a passing train.

Note that we make no guarantees about any of the determinations for species we saw. We were on vacation, and just having fun seeing species we'd never seen before. Most determinations were made quickly, picking the most likely determination from Andre's list, and some of our determinations could be wrong.

Additional Observations From Our Trip

The following are somewhat random additional observations from our trip.

Checklist of Species Observed, with Species in Bloom Noted

Table 1 is sorted first by category in the same order as Andre's list - ferns, conifrs, dicots and monocots - and then by family and scientific name. The Family and Scientific Name are from the Jepson Manual 1993 First Edition.

The first two columns are from Trip 1, the 22-23 September trip. The column titled Obs. indicates whether a taxon was observed if there is an entry in the column. An entry of "X" indicates we saw a taxon. An entry of "sp" means we don't know which species it is, and a random one was picked just to indicate that we observed the genus. An entry of "ssp" means the same for subspecies, and same for "var".

The column titled Fl. indicates whether we observed at least one plant of that species in bloom. The number given in that column is the order in which RT Hawke recorded the species as being in bloom, and corresponds to the numbers given for each location in Fig. 1.

The column titled Trip 2 indicates species seen on the 29-30 September 2012 trip of RT and Shaun Hawke, Tim Thomas and Pam MacKay. Since all those species were from the New York Mountains, they are not numbered. That single column indicates both blooming (b) and non-blooming (X) species. Two Astragalus species are marked with "or", since this plant was not in bloom and could be either one of these two species.

Caveat on the bloom list: we counted grass species as in bloom if they had a recognizable inflorescence with intact spikelets; we did not look for fresh anthers or styles. We also didn't check for viable anthers or styles on the paintbrushes; if we saw red, we counted them in bloom. One species on the list, Mirabilis coccinea, wasn't technically in bloom, but it was a species most of us had not seen before, and like the grasses, there was enough of an inflorescence in good shape to identify it. Hey, we were on vacation, and especially interested in species we hadn't seen before. (:-)

Table 1. Checklist of Species Observed, with Species in Bloom Noted

Scientific NameTrip 1Trip 2
Pteridaceae (Brake Family)   
Pellaea mucronata var. mucronata  X
Cupressaceae (Cypress Family)   
Juniperus californicasp X
Juniperus osteospermaX X
Ephedraceae (Ephedra Family)   
Ephedra nevadensissp45X
Pinaceae (Pine Family)   
Pinus monophyllaX  
Amaranthaceae (Amaranth Family)   
Amaranthus albusX67 
Amaranthus blitoides  X
Amaranthus fimbriatusX12b
Amaranthus torreyi  b
Anacardiaceae (Sumac Family)   
Rhus trilobataX X
Asclepiadaceae (Milkweed family)   
Asclepias asperula ssp. asperulaX X
Asclepias erosasp  
Asclepias subulataX7 
Asteraceae (Sunflower Family)   
Adenophyllum cooperiX25 
Ageratina herbacea  b
Ambrosia acanthicarpaX29 
Ambrosia artemisiifolia  b
Ambrosia eriocentraX X
Artemisia bigelovii  b
Artemisia dracunculus  X
Artemisia ludoviciana ssp. albulaX60X
Artemisia tridentata ssp. tridentataX X
Baccharis sergiloidesX99X
Baileya multiradiata var. multiradiataX24b
Brickellia californicaX78b
Brickellia incanaX31 
Brickellia oblongifolia var. linifoliaX110b
Chaetopappa ericoidesX58b
Chrysothamnus depressus?  
Chrysothamnus nauseosus ssp. hololeucusX b
Chrysothamnus paniculatusX37 
Cirsium arizonicum var. tenuisectumX89b
Encelia actoniX57 
Encelia frutescensX18 
Encelia virginensisX106 
Ericameria cooperi var. cooperiX82b
Ericameria cuneata var. spathulataX X
Erigeron concinnus var. concinnus  b
Gutierrezia microcephalaX b
Gutierrezia sarothraeX b
Hymenoclea salsola var. salsolassp X
Hymenopappus filifolius var. megacephalusX92X
Hymenoxys acaulis var. arizonicaX75b
Hymenoxys cooperiX98 
Machaeranthera arida  b
Machaeranthera canescens var. leucanthemifoliaX61b
Palafoxia arida var. aridaX6 
Pectis papposa var. papposaX1b
Psilostrophe cooperiX43b
Sanvitalia abertiiX73b
Schkuhria multiflora var. multifloraX86b
Senecio flaccidus var. monoensisX10 
Senecio multilobatus  b
Solidago velutinaX96b
Stephanomeria paucifloraX22b
Tetradymia argyraeasp  
Viguiera parishiib111b
Berberidaceae (Barberry Family)   
Berberis fremontiiX X
Berberis fremontii X Berberis haematocarpa  X
Chilopsis linearis ssp. arcuataX4X
Boraginaceae (Borage Family)   
Cryptantha flavoculata  X
Tiquilia plicataX40 
Brassicaceae (Mustard Family)   
Arabis perennans  b
Lepidium montanum var. cinereumX105b
Stanleya pinnata var. pinnataX93 
Cactaceae (Cactus Family)   
Escobaria vivipara var. roseavar var
Echinocereus engelmanniiX X
Echinocereus triglochidiatusX X
Ferocactus cylindraceus var. lecontei  X
Opuntia acanthocarpa var. coloradensisX X
Opuntia basilaris var. basilarisX X
Opuntia chloroticaX  
Opuntia echinocarpaX  
Opuntia parishiiX  
Opuntia phaeacanthaX X
Opuntia erinacea var. erinaceaX X
Capparaceae (Caper Family)   
Isomeris arboreaX  
Caprifoliaceae (Honeysuckle Family)   
Symphoricarpos longiflorus  X
Chenopodiaceae (Goosefoot Family)   
Atriplex canescensX X
Chenopodium fremontii  X
Krascheninnikovia lanataX X
Salsola paulsenii  b
Salsola tragussp88X
Crossosomataceae (Crossosoma Family)   
Glossopetalon spinescensX  
Cucurbitaceae (Gourd Family)   
Cucurbita foetidissimaX  
Arctostaphylos pungens  X
Euphorbiaceae (Spurge Family)   
Chamaesyce albomarginataX36b
Chamaesyce fendleri  b
Chamaesyce micromeraX33b
Chamaesyce polycarpaX3 
Chamaesyce revolutaX52b
Chamaesyce serpyllifoliaX76b
Chamaesyce setilobaX32 
Eremocarpus setigerusX17 
Euphorbia exstipulata var. exstipulataX77 
Tragia ramosaX59b
Fabaceae (Pea Family)   
Acacia greggiiX X
Astragalus bernardinus  X
Astragalus lentiginosus var. fremontiiX20b
Astragalus newberryi var. newberryi  or
Astragalus nutansX109 
Astragalus purshii var. tinctus  or
Caesalpinia gilliesiiX38 
Dalea searlsiaeX102b
Glycyrrhiza lepidota  X
Hoffmannseggia glaucaX69b
Lotus argyraeus var. multicaulis  ~
Psorothamnus arborescens var. minutifoliusX  
Senna armataX39 
Fagaceae (Oak Family)   
Quercus chrysolepisX X
Quercus turbinellaX X
Garryaceae (Silk Tassel Family)   
Garrya flavescensX X
Gentianaceae (Gentian Family)   
Swertia albomarginataX104b
Geraniaceae (Geranium Family)   
Erodium cicutarium  X
Hydrophyllaceae (Waterleaf Family)   
Eriodictyon angustifoliumX X
Krameriaceae (Rhatany Family)   
Krameria erectaX56b
Krameria grayiX34X
Lamiaceae (Mint Family)   
Marrubium vulgare  X
Salazaria mexicanaX46b
Salvia columbariaeX  
Salvia dorrii var. pilosaX47b
Salvia pachyphyllaX95 
Linaceae (Flax Family)   
Linum lewisiiX108X
Linum puberulumsp  
Loasaceae (Loasa Family)   
Petalonyx thurberi ssp. thurberiX5 
Malvaceae (Mallow Family)   
Sphaeralcea ambigua var. ambiguaX13b
Molluginaceae (Carpet-Weed Family)   
Mollugo cervianaX  
Nyctaginaceae (Four O'Clock Family)   
Abronia nana ssp. covilleiX103 
Allionia incarnataX  
Boerhavia coulteri  b
Boerhavia intermediaX49 
Boerhavia wrightiiX48b
Mirabilis bigelovii var. bigeloviiX50b
Mirabilis coccineaX62X
Mirabilis multiflora var. pubescensX87X
Mirabilis oblongifoliaX107 
Oleaceae (Olive Family)   
Forestiera pubescens  X
Menodora scopariaX70b
Menodora spinescensX X
Onagraceae (Evening Primrose Family)   
Camissonia californicaX  
Epilobium canum ssp. latifolium  b
Gaura coccineaX97b
Oenothera caespitosa ssp. crinita  sp
Oenothera californica ssp. avitaX28b
Polemoniaceae (Phlox Family)   
Ipomopsis arizonicaX90b
Leptodactylon pungensX101 
Polygalaceae (Milkwort Family)   
Polygala acanthocladaX54b
Polygonaceae (Buckwheat Family)   
Eriogonum deflexum var. deflexumX15 
Eriogonum fasciculatum var. polifoliumX9b
Eriogonum inflatumX44b
Eriogonum microthecum var. simpsoniiX68b
Eriogonum palmerianumX14b
Eriogonum plumatellaX16 
Eriogonum umbellatum var. juniporinum  b
Eriogonum wrightii var. wrightii  b
Portulacaceae (Purslane Family)   
Portulaca halimoides  X
Portulaca oleracea (native variety)X23X
Rhamnaceae (Buckthorn Family)   
Ceanothus greggii var. vestitusX X
Rhamnus californica ssp. californicaX b
Rhamnus ilicifolia  X
Rosaceae (Rose Family)   
Fallugia paradoxaX79b
Holodiscus microphyllus var. microphyllusX  
Prunus fasciculata var. fasciculataX X
Purshia mexicana var. stansburyanaX80b
Purshia tridentata var. glandulosaX X
Rubiaceae (Madder Family)   
Galium parishii  X
Salicaceae (Willow Family)   
Salix exigua  X
Scrophulariaceae (Figwort Family)   
Castilleja angustifoliaX51b
Castilleja linariifoliaX91b
Cordylanthus parviflorusX100 
Penstemon centranthifoliusX  
Penstemon eatonii var. eatoniiX83b
Penstemon palmeri var. palmeri  X
Penstemon rostriflorusX94b
Penstemon thompsoniae  b
Solanaceae (Nightshade Family)   
Datura wrightiiX11b
Lycium andersoniisp X
Lycium cooperi  X
Physalis hederifolia var. fendleriX53sp
Tamaricaceae (Tamarisk Family)   
Tamarix ramosissimaX21 
Aloysia wrightiiX55b
Verbena gooddingiiX63b
Viscaceae (Mistletoe Family)   
Phoradendron juniperinumX X
Zygophyllaceae (Caltrop Family)   
Kallstroemia californicaX41 
Kallstroemia parvifloraX85X
Larrea tridentataX30X
Tribulus terrestris  b
Cyperaceae (Sedge Family)   
Carex praegracilis  sp
Cyperus squarrosus  ~
Liliaceae (Lily Family)   
Yucca baccataX X
Yucca brevifoliaX X
Yucca schidigeraX  
Poaceae (Grass Family)   
Achnatherum c.f. coronatum  X
Achnatherum hymenoidesX X
Achnatherum parishiiX66 
Achnatherum speciosum  X
Aristida adscensionisX2 
Aristida purpurea var. fendlerianavar var
Bouteloua aristidoides var. aristidoidesX19b
Bouteloua barbata var. barbataX8b
Bouteloua curtipendulaX64b
Bouteloua eriopodaX71b
Bouteloua gracilisX72b
Bromus madritensis ssp. rubensX X
Bromus tectorumX81X
Elymus elymoides ssp. elymoides  X
Enneapogon desvauxii  b
Eragrostis cilianensisX65b
Eragrostis pectinacea var. pectinaceaX b
Erioneuron pulchellumX42X
Muhlenbergia fragilis  b
Muhlenbergia porteriX35b
Muhlenbergia rigensX84b
Pleuraphis jamesiiX74b
Pleuraphis rigidaX26b
Sporobolus cryptandrusX X
Zea maysX27 
Typhaceae (Cattail Family)   
Typha latifoliaX  

We thank Jim Andre for alerting us to the Mojave Desert bloom, pointing the way to the New York Mountains as the best spot, and help with identifying some of the species we saw. We thank Jane Strong for researching the rainfall for this area.

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Copyright © 2012 by RT Hawke, Shaun Hawke, Tom Chester, Kate Harper, Anne Kelly, Pam MacKay, Aaron Schusteff and Tim Thomas (authors listed alphabetically after RT and Shaun Hawke)
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Last update: 9 October 2012