Comments On the Flora of Western Riverside County

Table of Contents

Additions to the WRC Flora
Taxa In Nearby Areas Not In the WRC Flora
Deletions and Changed Identifications to the WRC Annotated Checklist
Comments on Individual Species in the WRC Annotated Checklist
Typos in the WRC Annotated Checklist


In late 2004, Fred M. Roberts, Jr., Scott D. White, Andrew C. Sanders, David E. Bramlet, and Steve Boyd released their first edition of The Vascular Plants of Western Riverside County, California: An Annotated Checklist. I will refer to it as the WRC Annotated Checklist henceforth, with WRC used to abbreviate Western Riverside County.

The WRC Annotated Checklist gives the first compilation of the flora of Western Riverside County, henceforth abbreviated WRC Flora. This paper gives a list of additional taxa found in the WRC Flora from the work of other authors and myself.

Although the WRC Annotated Checklist is called An Annotated Checklist, the annotation is extensive, and I would not have hesitated to call their book a Flora. This WRC Annotated Checklist represents an enormous amount of work, not only by the authors but by all the botanists who have collected vouchers from WRC in the past century and deposited them in a major herbarium. It is indeed the systematic and comprehensive summary of the flora of WRC that they claim it to be. The authors have intimate knowledge of many areas of WRC as well as intimate knowledge of the vouchers stored at the two main repositories of WRC plants, the Rancho Santa Ana and UC Riverside Herbaria. They have distilled this knowledge into a compact 192 page book that makes it very accessible to every botanist.

As expected, the book gives a brief description of the abundance, habitat and distribution for each taxon. But it also contains fascinating tidbits about the authors' feelings about the validity of some taxa (such as species and subspecies that are poorly separated from each other), and whether some taxa are declining or spreading. It is especially strong on including all non-native taxa growing within WRC, even if they are just urban weeds in irrigated areas. This is important, since today's urban weed might become tomorrow's noxious pest in wildlands. The authors also include observed hybrids, which are essential parts of a flora, but are oddly omitted in some floras.

The timing of the release of this book could not have been better for me, since at almost exactly the same time I began an intensive year of study of the flora of the trails of the Santa Rosa Plateau Ecological Reserve. I consulted this book regularly for the many specimens I analyzed during this period, and more than once it prevented me from making an error in the determination of a species name. The book also supplied a handful of sometimes-quite-surprising additions to the flora of the greater Santa Rosa Plateau region that will be useful when I update that. (See Flora of the Greater Santa Rosa Plateau Region for a discussion of the difference between the Santa Rosa Plateau Ecological Reserve and the Greater SRP Region.)

My vouchered survey of the flora of the trails of the Santa Rosa Plateau Ecological Reserve has resulted in a number of additions to the WRC Flora, as well as correcting a small number of misidentifications in the Lathrop and Thorne Santa Rosa Plateau Flora that was consulted by the authors of the WRC Annotated Checklist. As a result, I have compared the WRC Annotated Checklist to the Santa Rosa Plateau flora, and present the additions and corrections to the WRC Flora in this paper.

My database also includes the digitized floras of the San Mateo Canyon Wilderness Area (Boyd, Ross, Mistretta and Bramlet 1995), the Agua Tibia Mountains (Banks 1999), and the ongoing Santa Margarita Ecological Reserve survey by Michael Simpson and myself. I therefore also include here the additions to the WRC Flora from those surveys. Because each of those three areas includes portions outside of Riverside County, I consulted the original floras to include only taxa found within Riverside County.

The comparison found a total of 69 new taxa (52 native and 17 non-native) for the WRC Flora, increasing the number of taxa from 1411 to 1480 and the number of native taxa from 987 to 1039. In addition, I identified 10 other taxa that might be present in Riverside County, but whose locations in the other floras were not clear enough to determine the precise locations of those taxa. Another 94 taxa were found to be just outside the Riverside County line, and hence might be found to be present in Riverside County by future surveys.

Additions such as given here are entirely to be expected from the first edition of any flora that covers such a wide, disparate area, as the authors of the WRC Annotated Checklist are the first to admit. Compiling a flora for such a large and disparate area like WRC is far different from compiling a flora for a small region. Botanists do intensive field surveys, as well as herbarium searches, to compile a flora for a small region. It is not possible to carry out field surveys to compile a flora of such a large region, and hence the authors had to rely mostly on herbarium samples and their own experience, augmented by the small number of previous surveys of small areas within WRC. Compiling the initial list is the essential first step in obtaining a complete flora for such a large region. I'm happy to be able to contribute in a small way to the next revision of the WRC Annotated Checklist.

My work at the Santa Rosa Plateau also gave the subspecies for a taxon given only to the species in the WRC Annotated Checklist.

My familiarity with the floras of the Santa Rosa Plateau Ecological Reserve, Santa Margarita Ecological Reserve and Agua Tibia Mountains also enabled me to recognize where the WRC Annotated Checklist descriptions needed to be expanded to include those areas.

Finally, as I read through the WRC Annotated Checklist, I noted a few things that deserve mention, including identifying one listed taxon that is actually not present in Southern California (Brodiaea jolonensis). Removing this taxon decreases the final numbers given above by one native species.

All of the comments here are directed toward helping the WRC Annotated Checklist authors produce their second edition of their book, a small repayment for the information they have disseminated in their book.

The rest of this paper has five sections. The first gives the additions to the WRC Flora; the second gives species found in nearby areas that might be added to the flora in the future; the third gives deletions and changed identifications; the fourth gives comments on some of the taxa, including expanded ranges; and the fifth presents some typos I noticed in the WRC Annotated Checklist.

Additions to the WRC Flora

The following table gives the additions to the WRC Flora from the other floras mentioned above, which are all vouchered floras. See notes below the table for further information about some of these taxa.

Although each of these taxa was found inside Riverside County in at least one flora, note that an X in a column below does not guarantee that it was found inside Riverside County in every flora so marked.

The Santa Rosa Plateau Flora is abbreviated SRP, and the Santa Margarita Ecological Reserve Flora is abbreviated SMER.

FamilyScientific NameCommon NameAgua TibiaSRPSMERSan Mateo
ApiaceaeCicuta douglasii (DC.) J. Coulter & Rosewestern water hemlock  X 
AsteraceaeHesperevax acaulis (Kellogg) E. Greenedwarf evax X  
AsteraceaeLasthenia glaberrima A.DC.smooth goldfields X  
Asteraceae*Osteospermum ecklonis (DC.) NorlindhAfrican daisyX   
AsteraceaeStephanomeria exigua Nutt. ssp. exiguaslender wreathplantX   
BrassicaceaeCardamine californica (Torrey & A. Gray) E. Greene var. californicamilk maids X X
Brassicaceae*Cardamine hirsuta L.hairy toothwortX   
BrassicaceaeDescurainia pinnata (Walter) Britton ssp. glabra (Wooton & Standley) Detl.smooth western tansy-mustardX   
BrassicaceaeDraba verna L.spring drabaX   
BrassicaceaeLepidium densiflorum Schrader var. ramosum (Nelson) Thell.common pepper-grassX   
CampanulaceaeNemacladus longiflorus A. Gray var. breviflorus McVaughthread plantX   
ConvolvulaceaeCalystegia macrostegia (E. Greene) Brummitt ssp. cyclostegia (House) Brummittcoast morning-gloryX   
EricaceaeArctostaphylos glandulosa Eastw. ssp. glandulosaEastwood manzanita  XX
EricaceaeArctostaphylos glandulosa Eastw. ssp. glandulosa X A. rainbowensis J. Keeley & Massihihybrid Eastwood manzanita   X
EuphorbiaceaeChamaesyce micromera (Engelm.) Wooton & StandleySonoran spurge  X 
FabaceaeAstragalus didymocarpus Hook. & Arn. var. dispermus (A. Gray) Jepsondwarf white milk-vetchX   
FabaceaeAstragalus douglasii (Torrey & A. Gray) A. Gray var. parishii (A. Gray) M.E. JonesParish' Jacumba milk-vetchX   
FabaceaeLotus argophyllus (A. Gray) E. Greene var. argophyllus X L. heermannii (Durand & Hilg.) E. Greene var. heermanniihybrid lotusX   
Fabaceae*Pisum sativum peaX   
FabaceaeTrifolium depauperatum Desv. var. truncatum (E. Greene) Iselyballoon cloverXX X
Fabaceae*Vicia benghalensis L.purple vetch  X 
FagaceaeQuercus acutidens Torr.Torrey's scrub oak XX 
FagaceaeQuercus acutidens Torr. X Q. engelmannii E. Greenescrub oak X Engelmann oak X  
FagaceaeQuercus agrifolia Nee var. oxyadenia (Torrey) J. Howellsouthern coast live oakX   
GentianaceaeCentaurium exaltatum (Griseb.) Piperdesert centaury  X 
HydrophyllaceaeNemophila menziesii Hook. & Arn. var. integrifolia Parishbaby blue eyesXX X
HydrophyllaceaePholistoma membranaceum (Benth.) Constancewhite fiesta flowerX   
MalvaceaeSphaeralcea ambigua A. Gray var. rugosa Kearneydesert globemallowX   
Myrtaceae*Eucalyptus sideroxylon iron bark  X 
NyctaginaceaeAbronia umbellata Lam. ssp. umbellatapink sand verbena  X 
PolemoniaceaeAllophyllum gilioides (Benth.) A.D. Grant & V. Grant ssp. gilioidesdense false-gilia  X 
PolemoniaceaeEriastrum densifolium (Benth.) H. Mason ssp. austromontanum (Craig) H. Masonsouthern mountain woolly-starX   
PolemoniaceaeLinanthus bigelovii (A. Gray) E. GreeneBigelow's linanthusX   
PolygonaceaeEriogonum nudum Benth. var. pauciflorum S. Watsonnaked buckwheat X  
PortulacaceaeClaytonia parviflora Hook. ssp. viridis (Davidson) John M. Miller & Chambers X C. parviflora Hook. ssp. parvifloranarrow-leaved miner's lettuceX   
RanunculaceaeClematis lasiantha Nutt. X C. pauciflora Nutt.hybrid virgin's bowerX   
RanunculaceaeDelphinium parryi A. Gray ssp. maritimum (A. Davids.) Warnockblue larkspurX   
RanunculaceaeRanunculus occidentalis Nutt.western buttercup X  
RanunculaceaeThalictrum fendleri A. Gray var. fendleriFendler's meadow-rueX   
RhamnaceaeCeanothus crassifolius Torrey X C. ophiochilus Boyd, Ross & Arnsethhybrid ceanothusX   
RhamnaceaeRhamnus tomentella Benth. ssp. tomentellahoary coffeeberryX   
Rosaceae*Prunus dulcis (Miller) D. Webbalmond  X 
Rosaceae*Rubus discolor Weihe & NeesHimalaya blackberry X X
SaxifragaceaeLithophragma bolanderi A. GrayBolander's woodland starX X 
Scrophulariaceae*Kickxia spuria (L.) Dumort.roundleaf fluellin  X 
ScrophulariaceaeMimulus aurantiacus Curtis X M. clevelandii Brandegeehybrid monkeyflowerX   
ScrophulariaceaeVeronica americana (Raf.) Schwein.American speedwell X  
Tropaeolaceae*Tropaeolum majus L.nasturtium  X 
CyperaceaeEleocharis acicularis (L.) Roemer & Schultes var. bella Piperneedle spikerush X X
CyperaceaeScirpus pungens Vahlthree-square  XX
JuncaceaeJuncus bryoides F.J. Herm.moss rushX X 
JuncaceaeJuncus bufonius L. var. congestus Wahlenb.clustered toad rush X  
JuncaceaeJuncus phaeocephalus Engelm. var. paniculatus Engelm.spreading brown-headed rush X  
JuncaceaeJuncus phaeocephalus Engelm. var. phaeocephalusbrown-headed rush X  
LiliaceaeZigadenus venenosus S. Watson var. venenosusdeath-camasX   
OrchidaceaePiperia unalascensis (Sprengel) Rydb.Alaska rein orchid X  
Poaceae*Aegilops cylindrica Hostjointed goatgrass X  
Poaceae*Agropyron elongatum (Host) Beauv.tall wheatgrass X  
PoaceaeBromus anomalus Fourn.nodding brome   X
Poaceae*Ehrharta longiflora Sm.annual veldt grass  X 
PoaceaeElymus X macounii VaseyMacoun's ryegrass X  
Poaceae*Elytrigia repens (L.) Nevskiquackgrass X  
Poaceae*Hainardia cylindrica (Willd.) Greuterbarbgrass X  
Poaceae*Hordeum murinum L. ssp. murinumwall barley   X
PoaceaeLeymus Xmultiflorus (Gould) Barkworth & D.R. Deweyhybrid wild-ryeXX X
Poaceae*Poa infirma Kunth.weak blue grass X  
PoaceaePoa secunda J.S. Presl ssp. juncifolia (Scribner) R. Sorengrush blue grassX   
Poaceae*Polypogon viridis (Gouan) Breistr.    X
TyphaceaeTypha angustifolia L.narrow-leaf cattailXX   

Notes for some of the above taxa:

The following table gives taxa that might be present in Riverside County. I couldn't definitively tell if the taxa were inside or outside the county from the flora itself.

FamilyScientific NameCommon NameAgua TibiaSRPSMERSan Mateo
ApiaceaeOsmorhiza chilensis Hook. & Arn.mountain sweet-cicelyX   
AsteraceaeHulsea californica Torrey & A. GraySan Diego sunflowerX   
AsteraceaeStephanomeria cichoriacea A. Graychicory-leaved stephanomeria   X
Boraginaceae*Echium plantagineum L.salvation echium X  
CrassulaceaeSedum spathulifolium Hook.yellow stonecropX   
HydrophyllaceaePhacelia imbricata E. Greene ssp. imbricataimbricate phacelia   X
PlantaginaceaePlantago patagonica Jacq.Patagonia plantainX   
Solanaceae*Petunia violacea Lindl. X   
CyperaceaeCarex athrostachya Olneyslender-beak sedge   X
PoaceaeElymus trachycaulus (Link) Shinn. ssp. trachycaulusslender wheatgrassX   

Taxa In Nearby Areas Not In the WRC Flora

The following 94 taxa are not listed in the WRC Annotated Checklist, but are found just outside Riverside County. Future surveys might reveal that some of them are in fact present in Riverside County.

FamilyScientific NameCommon NameAgua TibiaSRPSMERSan Mateo
Amaranthaceae*Amaranthus arenicola I.M. Johnstonsandhill amaranthX   
Amaranthaceae*Amaranthus rudis J.D. Sauer X   
ApiaceaeHydrocotyle verticillata Thunb.whorled marsh-pennywortX   
ApocynaceaeApocynum androsaemifolium L.spreading dogbaneX   
AsteraceaeBaccharis vanessae Beauch.Encinitas baccharis   X
AsteraceaeHesperevax acaulis (Kellogg) E. Greene var. ambusticola Morefieldfire evaxX   
AsteraceaeHieracium albiflorum Hook.white hawkweedX   
AsteraceaeHulsea vestita A. Gray ssp. callicarpha (H.M. Hall) Wilkenbeautiful hulseaX   
AsteraceaeMachaeranthera juncea (E. Greene) Shinn.rush-like bristleweedX   
AsteraceaeMadia madioides (Nutt.) E. Greeneforest madiaX   
AsteraceaeMicroseris elegans A. Grayelegant silverpuffs   X
AsteraceaeSenecio astephanus E. GreeneSan Gabriel ragwortX   
AsteraceaeStephanomeria virgata Benth. ssp. pleurocarpa (Greene) Gottliebtwiggy wreath plantX   
BerberidaceaeBerberis pinnata Lagasca ssp. pinnatashiny-leaf barberryX   
BrassicaceaeArabis glabra (L.) Bernh.tower mustardX   
BrassicaceaeErysimum capitatum (Douglas) E. Greene ssp. capitatumwestern wallflowerX   
BrassicaceaeLepidium ramosissimum Nelson var. bourgeauanum (Thell.) Rollinsbranched pepper-grassX   
Cactaceae*Opuntia ficus-indica (L.) Millermission cactus  XX
CampanulaceaeGithopsis specularioides Nutt.common bluecupX   
CaprifoliaceaeLonicera hispidula Douglas var. vacillans A. Grayhairy honeysuckleX   
CaprifoliaceaeSymphoricarpos albus (L.) S.F. Blake var. laevigatus (Fern.) S.F. Blakesnowberry   X
CaryophyllaceaeCardionema ramosissimum (J.A. Weinm.) Nelson & J.F. Macbr.sandmatX   
Caryophyllaceae*Scleranthus annuus L. ssp. annuusknawelX   
ChenopodiaceaeChenopodium atrovirens Rydb.forest goosefootX   
Cucurbitaceae*Cucurbita pepo L. X   
EricaceaeArctostaphylos pringlei C. Parry ssp. drupacea (C. Parry) P. Wellspink-bracted manzanitaX   
EricaceaeChimaphila menziesii (D. Don) Sprengellittle prince's pineX   
EricaceaePterospora andromedea Nutt.pinedropsX   
EricaceaePyrola picta Smithwhite-veined wintergreenX   
EricaceaeRhododendron occidentale (Torrey & A. Gray) A. Graywestern azaleaXX  
Fabaceae*Gleditsia triacanthos L. X   
FabaceaeLotus nevadensis (S. Watson) E. Greene var. nevadensisSierra Nevada lotusX   
Fabaceae*Sutherlandia frutescens (L.) R. Br. X   
FagaceaeQuercus agrifolia Nee var. oxyadenia (Torr.) J.T. Howell X Quercus wislizeni A. DC.var. frutescens Engelm.hybrid oakX   
FagaceaeQuercus kelloggii Newb.California black oakX   
GrossulariaceaeRibes nevadense Kelloggmountain pink currantX   
HypericaceaeHypericum anagalloides Cham. & Schldl.tinker's penny X X
LamiaceaeSalvia apiana Jeps. X S. clevelandii (A. Gray) Greenegray sageX   
LamiaceaeSalvia sonomensis E. GreeneSonoma sageX   
LamiaceaeTrichostema austromontanum Harlan Lewis ssp. austromontanumsouthern bluecurls   X
OnagraceaeCamissonia robusta Ravenrobust sun-cupX X 
OnagraceaeClarkia delicata (Abrams) Nelson & J.F. Macbr.delicate clarkiaX   
OnagraceaeGayophytum diffusum Torrey & A. Gray ssp. parviflorum Harlan Lewis & J. SzweykowskigroundsmokeX   
PolemoniaceaeLinanthus ciliatus (Benth.) A. Greenewhisker-brushX   
PolemoniaceaeLinanthus orcuttii (C. Parry & A. Gray) JepsonOrcutt's linanthusX   
Polygonaceae*Polygonum prolificum (Small) Robinsonbushy knotweedX   
PortulacaceaeClaytonia exigua Torrey & A. Gray ssp. exigualittle spring beautyX   
RanunculaceaeAquilegia formosa Fischerwestern columbineX   
Resedaceae*Reseda alba L.white mignonetteX   
RhamnaceaeCeanothus crassifolius Torr. X C. greggii A. Gray var. perplexans (Trel.) Jeps.hybrid ceanothusX   
RhamnaceaeCeanothus leucodermis E. Greenehairy whitethornX   
RosaceaeHorkelia truncata Rydb.Ramona horkelia   X
Rosaceae*Malus sylvestris Millerdomestic apple   X
Rosaceae*Prunus persica BatschpeachX  X
RosaceaePrunus virginiana L. var. demissa (Nutt.) Torreywestern choke-cherryX   
Rosaceae*Pyrus sp.pear   X
RosaceaeRosa gymnocarpa Nutt.wood roseX   
RosaceaeRubus leucodermis Torrey & A. Graywhite-bark raspberryX   
RosaceaeRubus parviflorus Nutt.thimbleberryX   
RutaceaeCneoridium dumosum (Nutt.) BaillonbushrueX   
ScrophulariaceaeCastilleja applegatei Fernald ssp. martinii (Abrams) T.I. Chuang & Heckard X C. foliolosa Hook. & Arn.hybrid paintbrushX   
Scrophulariaceae*Digitalis purpurea L.purple foxglove   X
ScrophulariaceaeKeckiella ternata (Torrey) Straw var. ternatawhorledleaf penstemonX   
ScrophulariaceaePenstemon Xparishii A. GrayParish's penstemonX   
Solanaceae*Solanum marginatum L. f.white-margined nightshadeX   
Ulmaceae*Ulmus minor Millersmooth-leaved elm, English elmX   
VerbenaceaeVerbena lasiostachys Link var. scabrida Mold.western vervainX   
ViolaceaeViola purpurea Kellogg ssp. purpureagoosefoot violetX   
ViscaceaeArceuthobium campylopodum Engelm.pine dwarf-mistletoeX   
CupressaceaeCalocedrus decurrens (Torrey) Florinincense-cedarX   
PinaceaeAbies concolor (Gordon & Glend.) Lindleywhite firX   
PinaceaePinus jeffreyi Grev. & Balf.Jeffrey pineX   
PinaceaePinus torreyana CarriereTorrey pineX   
CyperaceaeCarex multicaulis L. Baileyforest sedgeX   
Cyperaceae*Scirpus tuberosus Desf.tubered bulrushX   
Iridaceae*Iris Xgermanica L.iris   X
JuncaceaeJuncus dubius Engelm.Mariposa rushX   
JuncaceaeJuncus patens E. Meyercommon rush   X
Liliaceae*Allium ampeloprasum L.    X
Liliaceae*Aloe arborescens Milleraloe   X
Liliaceae*Aloe chabaudii Schonl.aloe   X
LiliaceaeBrodiaea filifolia S. Watson X B. orcuttii (E. Greene) Bakerhybrid brodiaea   X
Liliaceae*Callicore rosea Linkamaryllis belladonna?   X
LiliaceaeNolina cismontana Dice X   
OrchidaceaeCorallorhiza maculata Raf.spotted coralrootX   
Poaceae*Agropyron desertorum (Fischer) Schultesdesert crested wheatgrassX   
Poaceae*Cortaderia selloana (Schultes) Asch. & Graebnerpampas grassX   
Poaceae*Dactyloctenium aegyptium (L.) Willd.crows-foot grassX   
PoaceaeElymus stebbinsii GouldStebbins' wildryeX   
PoaceaeFestuca californica Vasey var. parishii (Piper) A. Hithc.California fescueX   
Poaceae*Lolium perenne L.English rye-grassXXX 
DryopteridaceaePolystichum munitum (Kaulf.) C. Preslwestern sword fernX   
IsoetaceaeIsoetes nuttallii Engelm.Nuttall's quillwortX   
PteridaceaePentagramma triangularis (Kaulf.) G. Yatskievych, Windham & Wollenweber ssp. viscosa (D.Eaton) G. Yatsk., Windham & Wollenwebersilverback fernX   

Notes for some of the above taxa:

Deletions and Changed Identifications to the WRC Annotated Checklist

The following text gives deletions, possible deletions and changed identifications to the WRC Annotated Checklist:

Comments on Individual Species in the WRC Annotated Checklist

Page No.TaxonComment
24Daucus pusillusAlso widespread in grassland at the Santa Rosa Plateau.
24*Foeniculum vulgareFound in riparian areas at the Santa Rosa Plateau and Santa Margarita Ecological Reserve.
26*Vincetoxicum nigrum (Cynanchum louiseae Kartesz & Gandhi)The Jepson Interchange says this weed has been extirpated.
26*Acroptilon repensThere is also a 50 feet x 30 feet patch along Fault Road at the Santa Rosa Plateau Ecological Reserve that survived the 2001-2002 drought.
28Aster defoliatus (Aster bernardinus)I discovered a patch of this species at the Santa Rosa Plateau Ecological Reserve on 23 September 2005.
28Aster lanceolatus ssp. hesperiusThis occurs in at least three locations at the Santa Rosa Plateau Ecological Reserve, with two of the populations quite extensive.
30*Calyptocarpus vialisThe description, introduced from Texas or SE U.S., implies that is where this species is native. Some online sources also state that, but others, such as the USDA says this is introduced to the U.S. The Global Compendium of Weeds says it is native to Central America.
32*Cotula australisThis is actually a fairly common weed in natural habitats. The Agua Tibia Flora states: common in disturbed sites and drainages". The San Mateo Flora states: Uncommon but widespread in the wilderness.
32*Cynara cardunculusUnfortunately, this is also present at the Santa Rosa Plateau Ecological Reserve, and has proved difficult to eliminate there. It is occasional at San Mateo.
36*Gazania linearisAll floras report this as the Gazania species, yet all plants I have observed in wildlands have been the "bunching" hybrid that people have in their yards, with some leaves linear and some leaves compound, not the "trailing" kind with just linear leaves. The Sunset Western Garden Book says these are complex hybrids between a number of species. Compare this pix of Gazania linearis with this typical picture or this one of the garden plants.
37Gnaphalium californicumMy experience is that the flowers smell like maple syrup. The leaves have their own distinct odor, but it is not that of maple syrup.
37Gnaphalium canescens ssp. beneolensThis taxon is quite common at the Santa Rosa Plateau Ecological Reserve, and was misidentified by Lathrop and Thorne as Gnaphalium canescens ssp. microcephalum. See next entry.
37Gnaphalium canescens ssp. microcephalumThis taxon is actually quite scarce at the Santa Rosa Plateau Ecological Reserve. See previous entry.
37Gutierrezia sarothraeThe plants at the Santa Rosa Plateau Ecological Reserve are closer to G. sarothrae than to the G. californica determination of Lathrop and Thorne. See Plants of Southern California: Analysis Pages: Matchweed (Gutierrezia)
38*Hedypnois creticaThis is an extremely common species at the Santa Rosa Plateau Ecological Reserve, densely lining all the roads in the eastern part. It is so common that it is hard to believe it wasn't present in the 1985 Lathrop and Thorne flora. If it truly was absent in 1985, it has expanded rapidly across the Santa Rosa Plateau Ecological Reserve.
42Pluchea sericeaAlso present just over the county line at Santa Margarita Ecological Reserve along Stone Creek as it ends at the Santa Margarita River, and probably present upstream in Riverside County along similar drainages.
43Solidago californicaThis species has a different habitat at the Santa Rosa Plateau Ecological Reserve than described in the WRC Annotated Checklist. It is never found at seeps and canyon bottoms there; its SRPER habitat is up on the top of stream banks somewhat away from streams, as well as in moist shady areas with no obvious drainage nearby. Lathrop and Thorne say: frequent perennial of grassy clearings of oak woodland and chaparral-clad slopes. The San Mateo Flora says: common and widespread, especially in oak woodland understory, but also occurring in scrub, riparian and grassland habitats.
43Stephanomeria diegensisThis is a coastal species, but as far as I know, it is the only one of the S. diegensis / S. virgata pair in the Santa Ana Mountains, at least in their southernmost portion (although there is a report of S. virgata being locally common in Lucas Canyon in the San Mateo Flora that I need to check). The report of S. virgata in the Santa Rosa Plateau is incorrect; all those specimens are S. diegensis. See Plants of Southern California: Stephanomeria Geographic Distribution and links therein.
44Stephanomeria virgata ssp. virgataSee above entry.
49Plagiobothrys arizonicusThis was also reported as an infrequent annual in grasslands in the Santa Rosa Plateau Flora, although I've never seen it there.
49Plagiobothrys undulatusThis is locally common in the vernal pools at the Santa Rosa Plateau, not scarce. This taxon forms white rings around the Main Pool at times.
50Cardamine californica var. integrifoliaThere is something funny going on with the two varieties of this species, and perhaps neither variety is truly a distinct taxon. The history of variety integrifolia in Southern California is interesting.

Back in the days of Munz, only var. californica was said to occur in Southern California, with var. integrifolia being w. of main coast ranges, Monterey Co. to Humboldt Co. and having cauline lflets mostly oblanceolate and entire.

In 1993, Rollins apparently redefined integrifolia in Harvard Pap. Bot. 4: 44. 1993, and put the same in the JM. The main change was that integrifolia now was said to have lflets or lobes of cauline lvs gen oblong to linear, gen entire or teeth small, few or only 1 at tip. Quite a change from oblanceolate leaflets to oblong to linear leaflets!

The WRC Annotated Checklist is the only one in my database that reports var. integrifolia, although it was recently added to the San Diego County Flora. This may be just due to the fairly recent change in the circumscription of var. integrifolia.

I have surveyed the plants in the field at the Santa Rosa Plateau Ecological Reserve in two separate locations, and they clearly fit var. californica. The 20-30 plants at each location have almost entirely ovate, toothed cauline leaves, with only a single plant or two having its uppermost cauline leaves oblong and entire. This is why I put var. californica in the list of additions given above.

However, a similar survey at Torrey Pines State Reserve in San Diego County revealed a complete mix of the two varieties. For example, at one location I found 23 oblong, ~entire to 2-toothed leaflets; and 26 ovate, mostly toothed leaflets. In many cases, an individual plant had both kinds of leaves on it. Typically, the lowermost 1-2 cauline leaves would be ovate and toothed; the uppermost 1-2 cauline leaves would be oblong and ~entire, usually only with a terminal tooth.

Bottom line: the WRC Annotated Checklist should either list both varieties, or none at all.

53*Raphanus sativusThe WRC Annotated Checklist says apparently totally unsuccessful at establishment in the absence of soil disturbance, such as that generated by "weed control" programs. While it may be true that this is not an aggressive weed, it certainly establishes itself in some other places, primarily riparian. There are two patches at the Santa Rosa Plateau: one in a moist area along a trail, alongside Cirsium vulgare, and another in an undisturbed (but weedy) area between a trail and a road. It is also in an undisturbed canyon in the Laguna Mountains.
57Isomeris arboreaZach Principe discovered a plant at the corner of Cleveland National Forest Dr. and Tenaja Rd. at the Santa Rosa Plateau.
65Convolvulus simulansAlso discovered at the Santa Rosa Plateau Ecological Reserve, at Clay Hill, by Zach Principe.
66Cuscuta californica var. papillosaI discovered several populations at the Santa Rosa Plateau Ecological Reserve in 2005.
73Lupinus agardhianusAlso in the Santa Rosa Plateau flora, according to Lathrop and Thorne.
75Lupinus microcarpus var. microcarpusFairly common at the Santa Rosa Plateau.
80Erodium texanumZach Principe observed 3-10 individuals in 2001 just east of I-15 in Lake Elsinore
81*Geranium dissectumThis species is extremely common at the Santa Rosa Plateau, being present on all 16 plant trail guides in abundance. It is more abundant than Galium aparine, which is present on only 13 plant trail guides.
83Phacelia cryptanthaI have a late-season specimen from Borrego Palm Canyon that is a perfect P. cryptantha, but every plant in the main season at that location is Phacelia cicutaria var. hispida. If the single voucher specimen for the WRC Annotated Checklist is also a late-season plant, I'd be very suspicious of this determination.
90*Lythrum hyssopifoliumLythrum hyssopifolia (note spelling change) is extremely common at the Santa Rosa Plateau Ecological Reserve, being present on 13 of the 16 plant trail guides in extreme abundance, often lining the trails for some distance and dominant in some drainages.
99Plantago elongataI discovered a population of this at the Santa Rosa Plateau Ecological Reserve in 2005 in one location.
105Eriogonum fasciculatum vars. foliolosum and polifoliumThe Annotated Checklist says: The two subspecies sometimes occur together, yet never appearing to hybridize, and thus behaving as distinct biological species.

Oddly, this is almost the exact opposite of my experience! In many locations for my plant trail guides, I sometimes have a hard time declaring which specimen is "good enough" to be the first example of each taxon. For example, on the Dripping Springs Trail at Agua Tibia Mountain, I note at mile 1.64 the Beginning of transition region from var. foliolosum to var. polifolium, with the transition region ending at about mile 2.06. In this transition region, the plants take every form between the two varieties. Some day I plan to take leaf samples all along this trail, and take pictures of the transition from one variety to the other.

The Dripping Springs Trail is actually one of the cleanest transitions I've seen. At Daley Ranch in San Diego County, the plants appear mixed together with gradations between the two. Along the North Gate to Temecula Gorge trail at the Santa Margarita Ecological Reserve, it is often hard to call a specimen. In fact, this was a topic of discussion on a tour I led for the CNPS Riverside Chapter on that route. I have also found intermediate specimens in the foothills of the San Gabriel Mountains.

If there weren't large areas where only one of these varieties occur, I'd be suspicious that they were separate taxa.

105Eriogonum gracile vars. gracile and incultumI have only found var. gracile, with very clear tomentose inflorescence stems, at the Santa Rosa Plateau Ecological Reserve.
106*Polygonum lapathifoliumThe WRC Annotated Checklist gives this as non-native. This may be a typo, since every source I could find gives this as a native taxon. But since the range of this species extends to eastern North America, perhaps the authors of the WRC Annotated Checklist feel otherwise.

This taxon certainly behaves like a native taxon, since I have seen only a few specimens of this species.

108Claytonia perfoliata ssp. mexicanaThis is also common at the Santa Rosa Plateau.
108*Ranunculus sceleratusThis taxon has recently been found in San Diego County (see the September 2005 San Diego County Plant Atlas Newsletter, which is online but apparently can't be linked). Given the distribution of vouchers, it does not seem unreasonable that this is in fact native to Southern California.
113Rhamnus croceaDespite this species being said to be mostly absent from the Santa Ana Mountains, it is common at the Santa Rosa Plateau Ecological Reserve.
115*Galium muraleI found this in two separate locations at the Santa Rosa Plateau Ecological Reserve in 2005, which apparently triples the number of known locations in Southern California.
115*Galium parisienseThis has now turned up in a number of places in Southern California, including the Santa Rosa Plateau Ecological Reserve (in undisturbed coastal sage scrub), at Palomar Mountain, and at Daley Ranch. I have it on 7 plant trail guides, and in 8 floras in Southern California.
121Mimulus fremontiiAlso common in the Agua Tibia Flora
124Solanum parishiiThe plants in the Santa Rosa Plateau Flora called S. xanti are all actually clear specimens of Solanum parishii. The plants at Santa Margarita Ecological Reserve are also this taxon.
125Solanum xantiSee previous note.
133Cyperus esculentusAlso reported by Lathrop and Thorne at the Santa Rosa Plateau along De Luz Creek, but it isn't clear whether they vouchered specimens from Riverside County or San Diego County.
134Eleocharis acicularis var. acicularisThis taxon is a perennial, not an annual. The annual form is Eleocharis acicularis var. bella, in the list of additions to the WRC Annotated Checklist above.
136Chlorogalum pomeridianum var. pomeridianumCommon in grassland as well, at the Santa Rosa Plateau.
137Juncus phaeocephalus vars. phaeocephalus and paniculatus, J. oxymerisLathrop and Thorne reported J. oxymeris from the Santa Rosa Plateau, but their two vouchers were redetermined as J. phaeocephalus var. paniculatus, as reported in Boyd (2001). To further complicate this matter, I discovered only clear J. phaeocephalus var. phaeocephalus, with 5-7 heads per inflorescence, at the Santa Rosa Plateau Ecological Reserve in 2005.

The Flora of North America further speculates that Juncus phaeocephalus var. paniculatus, with more than 10 heads per inflorescence, perhaps should actually be classified as J. macrandus.

From all of the above, it seems likely that there is trouble in J. phaeocephalus / J. oxymeris land, with further study needed to straighten the species out.

143Aristida ternipes var. hamulosaZach Principe discovered this taxon at the Santa Rosa Plateau Ecological Reserve in 2002.
143*Brachypodium distachyonThere are two populations at the Santa Rosa Plateau Ecological Reserve, one of which is in a fairly surprising location: along the Vernal Pool Trail in the middle of the chaparral section, discovered in 2003.
146Elymus elymoidesI found a clear ssp. californicus at the Santa Rosa Plateau Ecological Reserve in 2005.
148*Hordeum marinum ssp. gussoneanumThere are a number of populations at the Santa Rosa Plateau Ecological Reserve, all in seasonally-moist drainages or seasonally-wet depressions in grassland.
149*Lolium perenneSee discussion above
150*Lolium temulentumUnfortunately, this species is well established and locally abundant at the Santa Rosa Plateau.
151Paspalum distichumThis species has now mostly taken over the Main Vernal Pool on the Mesa de Colorado at the Santa Rosa Plateau, and hence is now also found in vernal pools. It was not recorded to be present in any vernal pool by Lathrop and Thorne. It apparently came into the Pool after the water level was lowered in 1984 in order to restore it to the presumed level in the mid-19th century before the ranchers dammed the outlet.
155Brodiaea jolonensisThis taxon is only found in northern California, and should be deleted from the WRC Annotated Checklist; see discussion above
160Nemophila menziesii var. integrifoliaSee discussion above.

Typos in the WRC Annotated Checklist

Page No.TypoCorrection
525 meters (410 feet)125 meters (410 feet)
6the historical alluvial plains of the tributaries from the San Gabriel Mountainsthe historical alluvial plains of the tributaries from the easternmost San Gabriel Mountains
7Figure at top of page apparently labels the entire white area connected to the Banning Pass with that nameI suspect that portion should be labeled San Timeteo Canyon. Answer from Fred Roberts: the name does indeed apply to the entire white area, so the label should be moved to extend across the dotted line to make that clear.
10Total Pteridophytes: 1Total Pteridophytes: 31
11well labeled collectionswell-labeled collections
16Cystoperis fragilis and Cyrtomium falcatumout of alphabetical order
31Chaenactis artemisaefoliaChaenactis artemisiifolia
56under O. engelmannii in Appendix IIIunder O. engelmannii in Appendix I (note: there are three occurrences of this typo on this page)
60Spergularia macrotheca var. luecanthaSpergularia macrotheca var. leucantha
65Calystegia occidentalis ssp. fulcrataOut of alphabetical order.
77so it's statusso its status
78Quercus wislizeniiQuercus wislizeni (in two locations on the page)
85Leonotis nepetifolia (L.) R. Br.Leonotis nepetifolia (L.) W. T. Aiton.?? See the Jepson Interchange discussion for Leonotis leonurus.
88Lennoaceaeaout of alphabetical order
90Lythrum hyssopifoliumLythrum hyssopifolia
91Sidalcea malvaeflora ssp. sparsifoliaSidalcea malviflora ssp. sparsifolia
107californicusRechcalifornicus Rech
110Ranunculus californicaRanunculus californicus
115Populus fremontii ssp. fremontii X P. balsamifera ssp. trichocarpaPopulus balsamifera ssp. trichocarpa X P. fremontii ssp. fremontii
118Castilleja densiflorusCastilleja densiflora
125Fremontodendron californicum var. californicumFremontodendron californicum ssp. californicum. IPNI lists no valid names using variety.
125Tamarix aralensisout of alphabetical order
141Aristida pupurea var. nealleyiAristida purpurea var. nealleyi
152Secale ceraleSecale cereale
192Fred has hasFred has
192in addition to be involvedin addition to being involved
192California,RiversideCalifornia, Riverside


Banks, Darin L. 1999. A Vascular Flora of the Agua Tibia Mountains, Southern California. Rancho Santa Ana Botanic Garden Occasional Publications, No. 4. Rancho Santa Ana Botanic Garden, Claremont, California.

Boyd, S., Ross, Timothy S., Mistretta, Orlando and Bramlet, David. 1995. Vascular Flora of the San Mateo Canyon Wilderness Area, Cleveland National Forest, California. Aliso 14:109-139.

Chester, Thomas J. 2003. Santa Margarita Ecological Reserve: Preliminary Plant List by Trail,, 26 December 2003. (This is an older list; the current version of the list in my database was used for this paper.)

Chester, Thomas J. 2005. Flora of the Greater Santa Rosa Plateau Region,, 9 June 2005. (This is an older list; the current version of the list in my database was used for this paper.)

Chester, Thomas J. 2005. Flora of the Trails of the Santa Rosa Plateau Ecological Reserve,, 9 June 2005. (This is an older list; the current version of the list in my database was used for this paper.)

Lathrop, Earl W. and Thorne, Robert F. 1985. A Flora of the Santa Rosa Plateau, Southern California. Southern California Botanists, Special Publication No. 1.

Roberts, Fred M., Jr., White, Scott D., Sanders, Andrew C., Bramlet, David E. and Boyd, Steve. 2004. The Vascular Plants of Western Riverside County, California: An Annotated Checklist, F.M. Roberts Publications, San Luis Rey, California.

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Copyright © 2005-2006 by Tom Chester
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Last update: 8 February 2006