Plant Guide to Waterfall Trail, Eaton Canyon, San Gabriel Mountains

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
Plant Communities and Floristics
Fieldwork Dates and Summary of List Changes With Time
The Plant Guide
Comments On Specific Species


Directions to the trailhead:
From I-210 East:
Take the Altadena Drive Exit, and go north on Altadena Drive.
From I-210 West: Take the San Gabriel Boulevard Exit (signed for Eaton Canyon Nature Center), continue past Sierra Madre to Altadena Drive, and turn right (north) on Altadena Drive.

Take Altadena Drive north about 2.5 miles to Crescent Drive and turn right. Turn right at the next block, Pinecrest Drive. The trailhead for the Mt. Wilson Toll Road is at the gate as Pinecrest Drive curves left. Take the Toll Road 0.16 miles to the end of the Bridge. Take the Eaton Canyon Park Main Road right to the streambed, then go right on the trail which will take you under the bridge.

Parking on Pinecrest Drive is limited to 2 hours on the weekdays and not at all on the weekends, thanks to the selfish neighbors there (see 26-1 Eaton Canyon Nature Center to Henninger Flats). So if you'll be there more than 2 hours, simply park one block away.

See also Eaton Canyon and Flora of Lower Eaton Canyon.

Highlights of This Trail

This trail is primarily riparian. You cross the stream many times, and never stray far from it.

Our list contains 70 taxa, of which 64 have so far been identified, in about 0.76 miles of trail. Of these 64 taxa, 15 (23%) are non-native. These numbers are all roughly average for trails at this elevation.

Compared to the rest of our trails, this trail is low in the number of native taxa. This quite likely could be due to the incompleteness of the guide. However, it could also be due to the high number of invasive non-native species here, especially eupatory, which has displaced many native species.

The botanical highlights of this trail are:

Plant Communities and Floristics

Number of Unique Taxa On This Trail

The following histogram gives the number of trails in our database that contain each taxon on this trail. We had 73 trails in our database when this histogram was made; 3 of those trails, including this one, are in Eaton Canyon. A number of "1" means the taxon has only been found on this trail among the trails in our database; numbers of "3" or smaller may indicate taxa found only in this area.

We have two additional trails about six miles to the west / northwest.

Number of Trails
Containing A Taxon
Number Of Taxa
On This Trail
% of Taxa
On This Trail
Total Taxa64100%

We found 6 additional species not in the above table, since they have not been 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 almost unique, to this trail or area, out of our 73 trails on 29 January 2004, are:

#allLatin NameCommon NameDistribution in Southern California / Distribution in Trail Guides
2common beggar-ticksBidens pilosa var. pilosaSW; also found on the Brown Mountain Fire Road ~six miles west.
2golden currantRibes aureum var. gracillimumSW; also found on the lower Arroyo Seco trail ~six miles west.
2round-leaved boykiniaBoykinia rotundifoliaUNCOMMON; TR, PR; also found on the Sturtevant Trail ~six miles east.
3Jerusalem oakChenopodium botrysMost of CA; also found on the Mt. Wilson Toll Road Loop and a single plant on the Manzanita Trail.

This is the only trail on which we have seen Venus-hair fern, Adiantum capillus-veneris, but it is not reachable from the trail. One sees quite a lot of it at the waterfall, but it is out of reach. Free samples sometimes can be found floating in the water below the plants.

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"

The Plant Guide

Version for printing, without lines and other text on this page (4 pages)

Miles#id?Common NameLatin Name#here#all
0.00   Begin guide in the bed of the wash, directly under the middle of the Toll Road Bridge, on the west (left) side of the stream, elevation 1200 feet.
0.00l1 mule fatBaccharis salicifolia5 / 528
0.00r2 *smilo grassPiptatherum miliaceum50 / 916
0.00b3 *common beggar-ticksBidens pilosa var. pilosa99 / 92
0.00l4 *redstem filareeErodium cicutarium10 / 232
0.00r5 *eupatoryAgeratina adenophora99 / 96
0.00r6 white alderAlnus rhombifolia20 / 99
0.00r7 Hooker's evening-primroseOenothera elata ssp. hirsutissima20 / 54
0.00r8 mugwortArtemisia douglasiana20 / 523
0.00l9 *greater periwinkleVinca major1 / 16
0.00r10 *shortpod mustardHirschfeldia incana20 / 938
0.00r11 *giant reedArundo donax20 / 37
0.00r12 arroyo willowSalix lasiolepis4 / 226
0.00b  Check for a different willow.
0.00l13 narrowleaf bedstrawGalium angustifolium ssp. angustifolium10 / 939
0.00r14 giant needlegrassAchnatherum coronatum20 / 918
0.01l15 California-asterLessingia filaginifolia var. filaginifolia30 / 538
0.01l16 California buckwheatEriogonum fasciculatum var. foliolosum20 / 538
0.01l17 branching phaceliaPhacelia ramosissima var. latifolia30 / 923
0.01l18 long-stemmed buckwheatEriogonum elongatum var. elongatum5 / 217
0.01l19 California brickellbushBrickellia californica10 / 523
0.01l20sspdeerweedLotus scoparius var. scoparius10 / 919
0.01l  Old metal structure - support for a gatepost?
0.01l  (sweet alyssum, Lobularia maritima)
0.02r21 *tree tobaccoNicotiana glauca10 / 915
0.02l22 coast live oakQuercus agrifolia var. agrifolia10 / 931
0.03l23 *sow thistleSonchus oleraceus1 / 121
0.03l  Vandalized old building; cross stream to right side
0.04r24 canyon live oakQuercus chrysolepis10 / 919
0.04l  (California blackberry, Rubus ursinus)
0.07   Trail turns left 90° and crosses stream to left side
0.09l25 short-leaved cliff-asterMalacothrix saxatilis var. tenuifolia20 / 99
0.12r26 laurel sumacMalosma laurina5 / 229
0.13l27 golden yarrowEriophyllum confertiflorum var. confertiflorum10 / 540
0.13l28 coffee fernPellaea andromedifolia5 / 217
0.13l29 common bedstrawGalium aparine20 / 520
0.13l  (fountain grass, Pennisetum setaceum)
0.14r  (ladder brake, Pteris vittata)
0.14   (sugar bush, Rhus ovata)
0.15l30 California coffeeberryRhamnus californica ssp. californica2 / 212
0.15l31 chicory-leaved stephanomeriaStephanomeria cichoriacea5 / 15
0.15   Cross stream to right side
0.16r32 California bayUmbellularia californica2 / 19
0.17r33 bigleaf mapleAcer macrophyllum1 / 16
0.17l  (common fig, Ficus carica)
0.17r34 poison oakToxicodendron diversilobum10 / 329
0.17l35 *common chickweedStellaria media99 / 916
0.18r36 *horehoundMarrubium vulgare1 / 120
0.19r37?small-flowered melica?Melica imperfecta?10 / 3 
0.20l38?unk thistle?3 / 3 
0.20l39 horseweedConyza canadensis5 / 124
0.21   Cross stream to left side
0.22l40 *Spanish broomSpartium junceum1 / 17
0.24l41~wild sweetpeaLathyrus vestitus var. vestitus1 / 17
0.26r42 white nightshadeSolanum douglasii5 / 512
0.26l  Jct. high alternate path.
0.27l43 southern miner's lettuceClaytonia perfoliata ssp. mexicana20 / 314
0.27l44 golden currantRibes aureum var. gracillimum1 / 12
0.28l45 white everlastingGnaphalium canescens ssp. microcephalum5 / 530
0.28l46 bush monkeyflowerMimulus aurantiacus2 / 231
0.29r  Jct. short trail to right side of stream; continue straight.
0.29l47 black sageSalvia mellifera1 / 129
0.31l  Jct. other end of high alternate path.
0.31r48 birch-leaf mountain-mahoganyCercocarpus betuloides var. betuloides1 / 114
0.33l49 California blackberryRubus ursinus5 / 112
0.33   Cross stream to right side
0.37r50~eucryptaEucrypta chrysanthemifolia var. chrysanthemifolia10 / 115
0.38l  Jct. path
0.39r51 lemonade berryRhus integrifolia1 / 111
0.39r52 California lace fernAspidotis californica3 / 14
0.40r53 hillside gooseberryRibes californicum var. hesperium1 / 14
0.41l54 *Jerusalem oakChenopodium botrys10 / 13
0.42r  Large entranched side canyon.
0.46r55spCanterbury bells?Phacelia minor?10 / 1 
0.46r56 California suncupCamissonia californica10 / 113
0.46r57 *red bromeBromus madritensis ssp. rubens10 / 135
0.46r58 chiaSalvia columbariae10 / 117
0.46r59sppopcorn flowerCryptantha sp.3 / 1 
0.46r  Check for a different annual phacelia.
0.46r60 *windmill pinkSilene gallica10 / 121
0.47r61 collar lupineLupinus truncatus3 / 116
0.47r62 threadstemPterostegia drymarioides1 / 114
0.48r63spbittercressCardamine sp.3 / 1 
0.51   Cross stream to left side
0.52   Y-jct; go left, up.
0.53r64 creek senecioSenecio flaccidus var. douglasii1 / 19
0.53l65~Vasey's prickly pearOpuntia Xvaseyi1 / 115
0.54b66 chaparral yuccaYucca whipplei3 / 120
0.55l67~hollyleaf redberryRhamnus ilicifolia1 / 131
0.59   Y-jct; stay left (right branch crosses the stream)
0.60   Cross stream to right side
0.62   Cross stream to left side
0.67r68?smooth cat's ear?Hypochaeris glabra?10 / 1 
0.67r69~arched elegant rock-cressArabis sparsiflora var. arcuata5 / 36
0.70   Cross stream to right side
0.73   Cross stream to left side
0.76r70~round-leaved boykiniaBoykinia rotundifolia2 / 12
0.76r  (Venus-hair fern, Adiantum capillus-veneris)
0.76   End guide at waterfall, elevation ~1340 feet.

Comments On Specific Species

Hordeum murinum. These are perfect ssp. leporinum in Munz, with 4.7 spikelets per cm of rachis, male lateral spikelets, and an inflorescence that is partially sheathed. However, they key to ssp. glaucum in JM, with the central floret slightly < lateral florets and the anthers of lateral florets ~2x anthers of central floret! The central lemma awn is slightly longer than the lateral lemma awns, not shorter, per the JM description.

Hence we have chosen to not give a subspecies here, and will accumulate further data from other locations to see how common this situation is.

Lotus scoparius var. brevialatus. The subspecies was determined from plants later on the trail; thus it is possible that this specimen is var. scoparius, since both varieties are found in the vicinity.

Dichelostemma capitatum ssp. capitatum. Only leaves were seen at this location, hence the ~ in the id? column. This taxon was found later on the trail.

Cupressus sp., Pinus sp., Quercus lobata, Robinia pseudoacacia, and Casuarina equisetifolia. The Sierra Club hikers who use this trail, in a well-intentioned by uninformed action, planted these species along the south side of the trail to eventually provide shade for hikers and bikers along this very unshaded route.

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Copyright © 2003-2004 by Jane Strong and Tom Chester.
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: Jane Strong | Tom Chester
Updated 11 May 2004.