Plant Guide to Mt. Wilson Trail

This is a working list, about which we make no guarantees at all until we officially release it. Use at your own risk!

Introduction and Explanation of Plant Trail Guides

Highlights of This Trail
Fieldwork Dates and Summary of List Changes With Time
Botanical Trip Reports
The Plant Guide
Comments On Specific Species


The trailhead is at Mira Monte and Mt. Wilson Trail, in Sierra Madre (just north of Arcadia). See map.

Highlights of This Trail

The botanical highlights of this trail are:

Number of Unique Taxa On This Trail

The following histogram gives the number of trails in my database that contain each taxon on this trail. We had 89 trails in our database when this histogram was made; 7 trails, including this one, are in this south foothill area of the San Gabriel Mountains. A number of "1" means the taxon has only been found on this trail among the trails in our database; numbers of "7" or smaller may indicate taxa found only in this area.

Number of Trails
Containing A Taxon
Number Of Taxa
On This Trail
% of Taxa
On This Trail
Total Taxa126100%

We found 23 additional species not in the above table, since they have not been fully identified yet. The unidentified ones are marked with ? or sp in the id? column in the guide, and have no entries in the #all column.

The taxa that are unique, or nearly so, to this trail are:

#allLatin Name
1~Acacia baileyana
1~Rupertia physodes
1Lantana montevidensis
1Hedera helix
1Cosmos bipinnatus
2Chasmanthe floribunda
2Ceanothus oliganthus var. sorediatus
2~Phoenix canariensis
2~Phacelia imbricata ssp. imbricata
3~Acacia longifolia
3~Quercus berberidifolia X Q. engelmannii
3Crassula ovata
3Nerium oleander
4~Pinus halapensis
4Quercus durata var. gabrielensis X Q. engelmannii
4Brickellia nevinii
4Bidens pilosa var. pilosa
4~Clarkia unguiculata

Taxa with "~" before their name have not been definitely identified yet.

Fieldwork Dates and Summary of List Changes With Time

The following table gives the dates the trail was walked and taxa recorded. After each visit, the table gives the total number of taxa on the list and the breakdown of the taxa without positive identification. See Explanation of Plant Trail Guides to understand the symbols below.

Visit DateVisit ## taxa# "?"# "sp"# "~"# "ssp"

In addition, Michael Charters found the cosmos on a hiking trip on 2/4/05.

We thank Jane Strong for considerable assistance in helping us with miles 0.00-0.28.

Botanical Trip Reports

14 December 2004
15 January 2005

The Plant Guide

Version for printing, without lines and other text on this page (6 pages)

The mileages have been rectified to a GPS recording of the trail on 1/27/05, and should be accurate to within a few hundredths.

Miles#id?Common NameLatin Name#here#all
0.00r  Begin guide at trail sign-in post; elevation 1000 feet (305 m). Check for german ivy, Senecio mikanioides, offtrail to left.
0.00l1 *Bermuda buttercupOxalis pes-caprae99 / 97
0.00r2 *sow thistleSonchus oleraceus20 / 928
0.00b3 *smilo grassPiptatherum miliaceum99 / 920
0.00b4~*Cootamundra wattleAcacia baileyana2 / 21
0.00l5 wild-cucumberMarah macrocarpus var. macrocarpus20 / 942
0.00b6 coast live oakQuercus agrifolia var. agrifolia / 43
0.00l7 poison oakToxicodendron diversilobum50 / 943
0.00l  (American agave, Agave americana)
0.00r9 *common chickweedStellaria media99 / 922
0.02l  (chasmanthe, Chasmanthe floribunda)
0.02l10~*golden wattleAcacia longifolia1 / 13
0.02r11 laurel sumacMalosma laurina10 / 940
0.02l12 San Gabriel Mtns. leather oakQuercus durata var. gabrielensis10 / 95
0.02l13?baby plant like cheeseweed, Malva parviflora
0.03r14 heartleaf penstemonKeckiella cordifolia30 / 926
0.04r15 hollyleaf redberryRhamnus ilicifolia10 / 942
0.04l16 toyonHeteromeles arbutifolia10 / 944
0.04r17 *greater periwinkleVinca major5 / 18
0.04l18spgooseberryRibes sp.2 / 2 
0.04l19 southern honeysuckleLonicera subspicata var. denudata10 / 940
0.04r20?unk young annual, rosette of lvs like an Asteraceae
0.04r21 *petty spurgeEuphorbia peplus10 / 19
0.04r22spphacelia or eucrypta
0.04r23 blue elderberrySambucus mexicana1 / 144
0.05r24spyoung 3 needle pinePinus sp.1 / 1 
0.06r25spannual grass
0.06b26~bittercressCardamine oligosperma30 / 96
0.07r27~*bur chervilAnthriscus caucalis30 / 58
0.07r28 black sageSalvia mellifera10 / 939
0.07r29 California sagebrushArtemisia californica10 / 944
0.08r  (unidentified planted tree)
0.08l30 Southern California black walnutJuglans californica var. californica1 / 16
0.09r31 short-leaved cliff-asterMalacothrix saxatilis var. tenuifolia20 / 912
0.10r32~scrub oak X Engelmann oakQuercus berberidifolia X Q. engelmannii+2 / 23
0.10r33 coffee fernPellaea andromedifolia5 / 522
0.10l34 hollyleaf cherryPrunus ilicifolia ssp. ilicifolia10 / 912
0.10l35 *shortpod mustardHirschfeldia incana30 / 951
0.10r36 *jade plantCrassula ovata1 / 13
0.12r37~common rupertiaRupertia physodes10 / 31
0.12r38 mule fatBaccharis salicifolia1 / 136
0.12r39 *sweet alyssumLobularia maritima99 / 95
0.12r40?unk lily-like per?2 / 2 
0.13r41 *trailing lantanaLantana montevidensis5 / 11
0.13r42 *Australian brass-buttonsCotula australis10 / 115
0.13l43 annual sunflowerHelianthus annuus3 / 310
0.14l44 birch-leaf mountain-mahoganyCercocarpus betuloides var. betuloides20 / 918
0.16r45~Aleppo pinePinus halapensis1 / 14
0.16r46spaoniumAonium sp.1 / 1 
0.17l47 *chasmantheChasmanthe floribunda5 / 12
0.17r48 California buckwheatEriogonum fasciculatum var. foliolosum20 / 948
0.18r49?unk small plant like beeplant, sans a bad smell?3 / 1 
0.18r50 aloeAloe sp. /  
0.19   Trail has steps up to road; turn left on road
0.20r51 half-hairy ceanothusCeanothus oliganthus var. sorediatus2 / 22
0.20l52?unk per / ss?1 / 1 
0.20l  Sign: "Mt. Wilson Trail: First Water 1.3 [mi]; Orchard Camp 3.3; Manzanita Ridge ?; Mt. Wilson 6.8"
0.20r53 *English ivyHedera helix5 / 11
0.20r54 *oleanderNerium oleander1 / 13
0.21r  Fire hydrant; open gate across road
0.22b55 *redstem filareeErodium cicutarium99 / 950
0.22l56 *soft chessBromus hordeaceus / 38
0.22l57 *Bermuda grassCynodon dactylon1 / 126
0.22l58 *white-stemmed filareeErodium moschatum50 / 518
0.22l59 *California burcloverMedicago polymorpha30 / 539
0.22l  *cheeseweedMalva parviflora+10 / 118
0.22r60 chaparral yuccaYucca whipplei3 / 329
0.22r61 *slender wild oatsAvena barbata10 / 126
0.22l62 *goldentopLamarckia aurea10 / 113
0.22l63 bur-ragweedAmbrosia acanthicarpa1 / 115
0.22r64 *horehoundMarrubium vulgare1 / 130
0.23l  Sign: "No Campfires"
0.23l65~*Canary Island date palmPhoenix canariensis1 / 12
0.24l66ssp*foxtail barleyHordeum murinum10 / 13
0.24l67 white nightshadeSolanum douglasii3 / 315
0.26l  Jct. use path; Trail rounds ridge to left
0.26   Road curves left 90°
0.26r68 *ripgut bromeBromus diandrus10 / 145
0.26r69 *narrowleaf filagoFilago gallica20 / 543
0.27l70?unk small plant like beeplant, sans a bad smell, different from previous one
0.27l71 Engelmann - leather oak hybridQuercus durata var. gabrielensis X Q. engelmannii2 / 24
0.27l  (mission cactus, Opuntia ficus-indica)
0.28r72 wild sweetpeaLathyrus vestitus var. vestitus10 / 910
0.28l73sspdeerweedLotus scoparius var. scoparius20 / 923
0.28l74~*tocaloteCentaurea melitensis10 / 143
0.28r75~California chicoryRafinesquia californica10 / 920
0.29l76 blue dicksDichelostemma capitatum ssp. capitatum10 / 242
0.31l77 golden yarrowEriophyllum confertiflorum var. confertiflorum10 / 952
0.32r78~acourtiaAcourtia microcephala1 / 113
0.32l79 California polypodyPolypodium californicum20 / 316
0.33l80 goldback fernPentagramma triangularis ssp. triangularis20 / 523
0.33l81~*scarlet pimpernelAnagallis arvensis30 / 525
0.33l82 branching phaceliaPhacelia ramosissima var. latifolia30 / 933
0.33l83?California lace fernAspidotis californica+30 / 99
0.33l84 narrowleaf bedstrawGalium angustifolium ssp. angustifolium10 / 943
0.34r85?unk young plants, ternate leaf
0.34r86spvirgin's bower?Clematis lasiantha?10 / 1 
0.34l87 bicolored everlastingGnaphalium bicolor30 / 929
0.35l88 leafy daisyErigeron foliosus var. foliosus / 35
0.35l89 common bedstrawGalium aparine50 / 539
0.36l90~coast-range melicMelica imperfecta10 / 939
0.38l91 bush monkeyflowerMimulus aurantiacus5 / 541
0.38l92?unk honking rosetteVerbascum?1 / 1 
0.39   Trail turns right 90°
0.39l93 California brickellbushBrickellia californica30 / 928
0.39r94 *castor beanRicinus communis10 / 315
0.40l95 collar lupineLupinus truncatus10 / 522
0.40l96 California suncupCamissonia californica50 / 918
0.40l97 stinging lupineLupinus hirsutissimus20 / 913
0.40l98 *tree tobaccoNicotiana glauca5 / 119
0.40l99 south coast morning-gloryCalystegia macrostegia ssp. intermedia1 / 116
0.41l100 Nevin's brickelliaBrickellia nevinii10 / 94
0.42l101 chamiseAdenostoma fasciculatum1 / 137
0.44l102 small-seeded spurgeChamaesyce polycarpa30 / 912
0.44l103 giant needlegrassAchnatherum coronatum10 / 923
0.47l104 climbing bedstrawGalium nuttallii ssp. nuttallii5 / 530
0.48l105 long-stemmed buckwheatEriogonum elongatum var. elongatum10 / 923
? 106 *garden cosmosCosmos bipinnatus1 / 11
0.50   Trail rounds ridge to left
0.50r107 *mission cactusOpuntia ficus-indica1 / 16
0.52l108~chiaSalvia columbariae50 / 920
0.54r109 chaparral whitethornCeanothus leucodermis3 / 214
0.54l110~showy penstemonPenstemon spectabilis var. spectabilis1 / 112
0.56b111 California four o'clockMirabilis californica50 / 919
0.59   Switchback left at ridge
0.62r112~California dodderCuscuta californica var. californica1 / 115
0.64l113sspwestern thistleCirsium occidentale1 / 17
0.64l114?southern Indian pink?Silene laciniata ssp. major?1 / 1 
0.64l115 threadstemPterostegia drymarioides30 / 522
0.64l116 Bigelow's spike-mossSelaginella bigelovii20 / 518
0.66l117 California fuchsiaEpilobium canum ssp. canum5 / 117
0.67l118 scarlet larkspurDelphinium cardinale30 / 96
0.70l119 saw-toothed goldenbushHazardia squarrosa var. grindelioides1 / 134
0.70   Trail curves right at drainage
0.73l120 *common beggar-ticksBidens pilosa var. pilosa10 / 14
0.73l121 sugar bushRhus ovata2 / 224
0.75b122 wild pepper-grassLepidium virginicum var. pubescens5 / 16
0.77l123 wild canterbury bellsPhacelia minor20 / 915
0.77l124 white sageSalvia apiana2 / 235
0.79l  Switchback left at ridge; Jct. step use path (ridge route to Jones Peak)
0.79l125~elegant clarkiaClarkia unguiculata10 / 14
0.79l126?calochortus or muilla31
0.79l127spcloverTrifolium sp.20 / 5 
0.81l  Beautiful "hanging garden" of polypody and spike-moss
0.84l128spdudleyaDudleya lanceolata or D. cymosa10 / 5 
0.84l129 bird's-foot fernPellaea mucronata var. mucronata2 / 229
0.88l  Check for different delphinium
0.88l130 prickly cryptanthaCryptantha muricata50 / 515
0.88l131 *common groundselSenecio vulgaris30 / 516
0.88r132 California buckwheatEriogonum fasciculatum var. polifolium / 16
0.90l133 lace-podThysanocarpus laciniatus10 / 15
0.91l  eucryptaEucrypta chrysanthemifolia var. chrysanthemifolia+10 / 123
0.91r134 canyon live oakQuercus chrysolepis1 / 121
0.96l135?woodland star?Lithophragma sp.?1 / 1 
1.01l136 miner's lettuceClaytonia perfoliata ssp. perfoliata+50 / 523
1.02l137?chicory-leaved stephanomeria?Stephanomeria cichoriacea?2 / 2 
1.02l  Check for different sp., small rosettes of thin pinnate leaf
1.05r138spdifferent Brassicaceae?101
1.10l  Check for different phacelia.
1.11   Switchback left at jct. with original trail, now long-washed out.
1.12r139spsuncupCamissonia sp.50 / 2 
1.12r140?rattail fescue?Vulpia myuros? /  
1.14   Switchback right.
1.15   Switchback left.
1.17   Jct. fenced-off trail bypassed in 2004; continue straight
1.18l141 California bayUmbellularia californica1 / 112
1.20l142 California wood fernDryopteris arguta1 / 116
1.20   Switchback right.
1.21l143 yarrowAchillea millefolium5 / 112
1.24l  Check for Agoseris sp.
1.28r144 white everlastingGnaphalium canescens ssp. microcephalum1 / 136
1.32r145 purple nightshadeSolanum xanti1 / 112
1.45r  miner's lettuce population with mixed sspp.
1.45l146~imbricate phaceliaPhacelia imbricata ssp. imbricata5 / 12
1.47l147 California everlastingGnaphalium californicum1 / 141
1.49   Jct. bypassed trail at drainage
1.49r148 mugwortArtemisia douglasiana10 / 127
1.49   View of nice population of wallflower, Erysimum capitatum ssp. capitatum.
1.49r149 southern miner's lettuceClaytonia perfoliata ssp. mexicana+20 / 222
1.51   Jct. trail to First Water; elevation ~2040 feet (620 m); end plant guide.

Comments On Specific Species

Quercus berberidifolia X Q. engelmannii. This specimen surprised us greatly, since the scrub oaks in the area are all Q. durata var. gabrielensis, and not Q. berberidifolia or Q. acutidens. Nonetheless, there is no doubt that it has the 0.1-0.2 mm diameter white trichomes (hairs) of Q. berberidifolia or Q. acutidens mixed in with ~0.4 mm trichomes of Q. engelmannii. The leaves are completely lacking the ~1.0 mm trichomes of Q. durata var. gabrielensis. This unquestionably makes this scrub oak a hybrid of Q. engelmannii with either Q. berberidifolia or Q. acutidens.

Because the density of the trichomes is low, and due to the proximity to the Q. berberidifolia in the Santa Monica Mountains, we have tentatively gone with Q. berberidifolia X Q. engelmannii, but we will be checking it again in the future to see if it could in fact be Q. acutidens X Q. engelmannii.

Of course, given all the non-native planted specimens in this area, this specimen could have been planted here.

Malva parviflora, Eucrypta chrysanthemifolia var. chrysanthemifolia. These taxa are not numbered, since a previous unidentified plant may be the same taxa.

Aspidotis californica. Our written notes are a bit confusing here. The first noted occurrence of this taxon may in fact be a goldback fern. A definite Aspidotis californica was noted on the trail a short distance later.

Claytonia perfoliata. The subspecies intergrade on this trail in spots. Other spots show a clear dominance of one subspecies, but not as clear as on other trails in Southern California.

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Copyright © 2005 by Tom Chester and Michael Charters.
Permission is freely granted to reproduce any or all of this page as long as credit is given to us at this source:
Comments and feedback: Tom Chester | Michael Charters
Updated 6 February 2005.