Flora of S2 Mile Marker 0 to 4.6, San Diego County

This section of road is in the upper part of the Lake Henshaw basin, just above Buena Vista Creek following the north base of the Volcan Mountains, about midway between the spillway of Lake Henshaw and Ranchita, at elevations of 2836 to 3300 feet. Some sections are very similar to the Lake Henshaw grassland, and some sections are shrublands.

Mile Marker 0.0 for San Diego County Road S2 is at the junction with SR79 east of Lake Henshaw and south of Warner Springs, elevation 2836 feet. The road steadily increases in elevation to 3300 feet at Mile Marker 4.6 is at the junction with S22, Montezuma Valley Road.

We often stop along this section of S2 on our way to the Borrego Desert, and finally decided we might as well compile a list of some of the species we incidentally observed on our stops. To make the list more complete, we also added species from vouchers, which may or may not be present along the roadside.

Perhaps the most interesting taxon in the list before is the Warner Springs Lessingia, Lessingia glandulifera var. tomentosa, which only lives in the Lake Henshaw immediate drainage area, but which is abundant in this stretch of the road. At mile 0.4, it is intermixed with var. glandulifera, but then the roadside is solid var. tomentosa up to mile 4.55, where it is again mixed with var. glandulifera. We've stopped here numerous times to show fellow botanists var. tomentosa.

Three species, and probably a fourth, appear to be planted here. On the south side of S2, immediately west of the junction with S22, there is a line of Fraxinus velutina trees as well as at least one Pinus jeffreyi and one Hesperocyparis stephensonii. The last two species are considerably out of range in this area, and the habitat here doesn't look like typical Fraxinus velutina habitat. The Pinus coulteri have probably been planted along the roadside as well, but it is native to this general area.

The checklist was compiled from a search of the Consortium of California Herbaria on 15 August 2014, as well as from scattered stops along the road in 2005, 2013, 2014 and 2015. We specifically botanized the road at eight stops on 8 April 2015, when the area was in peak bloom, in order to make the flora more complete. See Photos from Fred Melgert from that survey.

We've made many more stops along here in other years, and we may gradually add observations from those stops as we come across those data.

One of the first times we stopped along this road was in October 2005, when we observed An April Bloom In October! here.

The vouchers came from a geographic search for georeferenced vouchers between 33.22 and 33.25° latitude, and -116.68 to -116.60° longitude. The localities of the vouchers were reviewed, and ones not clearly from the vicinity of S2 were tossed. A Parish voucher for Geraea viscida from the year 1880 was tossed, even though the locality says At Warner's Ranch and other elevated places in San Diego Co. since all other San Diego County vouchers are from southeast County.

The checklist as of 11 April 2015 contains 115 taxa from our observations, and an additional 105 taxa from vouchers from this area. Those voucher taxa may or may not be present along the road.

An asterisk before the common name indicates a taxon not-native to California.

See Information about the order in which the species are presented, the source for the Scientific Names, and the links from the Scientific Name and Common Name.

The column #V gives the number of vouchers for each species. Note that some of these vouchers might not have been taken from the immediate vicinity of S2.

The column Mile gives the mile marker for the first location at which we observed a given taxon. If the column contains an x, we have observed that taxon somewhere in this section, but do not have a precise location. If the column contains a V followed by a mile marker, it was vouchered at that mile marker.

You can easily locate a given mile marker by starting at the junction with SR79 and resetting your trip odometer to zero. Your trip odometer will then correspond to the mile markers.

Version for printing, without lines and other text on this page: html (6 pages) or pdf Clickbook booklet (2 double-sided pages). (See printing instructions for an explanation of these options)

#FamScientific Name(*)Common Name#VMile
1PtePellaea mucronata var. mucronatabird's-foot fern1 
2PtePentagramma triangularis ssp. triangularisgoldback fern1 
3CupHesperocyparis stephensoniiCuyamaca cypress14.5
4PinPinus coulteriCoulter pine 0.4
5PinPinus jeffreyiJeffrey pine 4.5
6AdoSambucus nigra ssp. caeruleablue elderberry20.4
7AmaAmaranthus albus*tumble pigweed 0.4
8AmaAmaranthus fimbriatusfringed amaranth 4.6
9AmaAmaranthus hybridus*slim amaranth 2.0
10AmaAmaranthus palmeriPalmer's amaranth 4.3
11ApiBowlesia incanahoary bowlesia1 
12ApiSanicula bipinnatifidapurple sanicle1 
13ApiTauschia argutasouthern tauschia1 
14ApiTauschia parishiiParish's tauschia1 
15ApoAsclepias eriocarpaIndian milkweed1 
16AstAchillea millefoliumyarrow1 
17AstAgoseris heterophyllaannual agoseris1 
18AstAgoseris retrorsaspear-leaved mountain dandelion 0.4
19AstAmbrosia acanthicarpabur-ragweed 0.4
20AstAnisocoma acaulisscale-bud2 
21AstArtemisia dracunculuswild tarragon 0.6
22AstArtemisia tridentatabig sagebrush 0.3
23AstBaccharis salicifolia ssp. salicifoliamule fat12.8
24AstCentaurea benedicta*blessed thistle 0.6
25AstChaenactis artemisiifoliameally white pincushion 2.0
26AstChaenactis glabriuscula var. glabriusculayellow pincushion1 
27AstChaenactis glabriuscula var. lanosawoolly yellow chaenactis10.4
28AstCirsium scariosumelk thistle3 
29AstCorethrogyne filaginifoliaCalifornia-aster10.4
30AstCotula coronopifolia*brass-buttons1 
31AstEncelia actoniActon encelia2 
32AstEricameria pinifoliapine goldenbush1 
33AstErigeron canadensishorseweed 2.0
34AstErigeron foliosus var. foliosusleafy daisy 1.0
35AstEriophyllum confertiflorum var. confertiflorumgolden yarrow1 
36AstEriophyllum wallaceiWallace's woolly daisy1 
37AstGutierrezia californicaCalifornia matchweed10.4
38AstGutierrezia sarothraematchweed1 
39AstHeterotheca grandifloratelegraph weed 0.4
40AstIsocoma acradenia var. eremophilasolitary-leaved alkali goldenbush1 
41AstLagophylla ramosissimacommon hareleaf 2.0
42AstLasthenia gracilisgoldfields20.3
43AstLayia glandulosawhite tidy-tips2 
44AstLeptosyne californicaCalifornia coreopsis 0.4
45AstLessingia glandulifera var. glanduliferasticky lessingia 0.4
46AstLessingia glandulifera var. tomentosaWarner Springs lessingia70.4
47AstLogfia depressadwarf filago1 
48AstLogfia gallica*narrowleaf filago1 
49AstMalacothrix californicaCalifornia dandelion40.4
50AstMalacothrix clevelandiiannual malacothrix1 
51AstMatricaria discoidea*pineapple weed10.3
52AstMicropus californicus var. californicusslender cottonweed3 
53AstPseudognaphalium beneolensfragrant everlasting 2.0
54AstPseudognaphalium californicumCalifornia everlasting1 
55AstPseudognaphalium luteoalbum*common cudweed1 
56AstSenecio californicusCalifornia groundsel10.6
57AstSenecio flaccidus var. monoensisMono ragwort1 
58AstSolidago velutina ssp. californicagoldenrod 1.0
59AstSonchus asper ssp. asper*prickly sow thistle 2.0
60AstStephanomeria exigua ssp. deaneislender wreathplant 0.4
61AstStylocline gnaphaloideseverlasting nest-straw1 
62AstUropappus lindleyisilver puffs20.4
63AstWyethia ovatasouthern mule's ears1 
64BigChilopsis linearis ssp. arcuatadesert-willow1 
65BorAmsinckia intermediacommon fiddleneck 0.3
66BorAmsinckia retrorsasmall-flowered fiddleneck20.4
67BorCryptantha intermedia var. intermediapopcorn flower30.4
68BorCryptantha micrantha var. lepidamountain red-root cryptantha1 
69BorEmmenanthe penduliflora var. penduliflorawhispering bells11.0
70BorEriodictyon trichocalyxsmoothleaf yerba santa1 
71BorNemophila menziesiibaby blue eyes50.4
72BorNemophila menziesii var. integrifoliababy blue eyes1 
73BorNemophila menziesii var. menziesiibaby blue eyes1 
74BorPectocarya linearis ssp. feroculaslender combseed 0.3
75BorPectocarya penicillatacombseed20.6
76BorPhacelia brachylobashort-lobed phacelia1 
77BorPhacelia cicutaria var. hispidacaterpillar phacelia 2.0
78BorPhacelia distanscommon phacelia22.4
79BorPhacelia imbricata ssp. patulaimbricate phacelia 1.4
80BorPhacelia minorwild canterbury bells21.0
81BorPhacelia ramosissimabranching phacelia1 
82BorPlagiobothrys arizonicusArizona popcorn flower40.3
83BorPlagiobothrys canescens var. canescensgrey popcorn flower2 
84BorPlagiobothrys tenellusslender popcorn flower10.4
85BraBoechera californicaCalifornia elegant rock-cress1 
86BraCaulanthus heterophyllus var. heterophyllusSan Diego jewelflower1 
87BraCaulanthus simulansPayson's wild cabbage1 
88BraDescurainia pinnatawestern tansy-mustard1 
89BraDescurainia sophia*herb sophia1V1.0
90BraErysimum capitatum var. capitatumwestern wallflower2 
91BraHirschfeldia incana*shortpod mustard 0.3
92BraLepidium lasiocarpum ssp. lasiocarpumhairy-podded pepper-grass1 
93BraLepidium nitidumshining peppergrass1 
94BraNasturtium officinalewater cress2 
95BraSisymbrium altissimum*tumble-mustard10.4
96BraSisymbrium orientale*Oriental mustard 1.0
97BraThysanocarpus laciniatuslace-pod1 
98CacCylindropuntia californica var. parkericane cholla 2.8
99CacOpuntia phaeacanthadesert prickly-pear1 
100CarCerastium glomeratum*mouse-ear chickweed1 
101CarSpergularia bocconi*sand spurrey 0.3
102CheAtriplex canescens var. canescens (s.l.)four-wing saltbush 0.4
103CheChenopodium californicumCalifornia goosefoot1 
104CheSalsola tragus*Russian thistle 0.4
105CucCucurbita foetidissimastinking gourd 1.3
106CucMarah macrocarpawild-cucumber1 
107EriArctostaphylos glaucabigberry manzanita2 
108EupChamaesyce albomarginatarattlesnake weed10.4
109EupChamaesyce serpyllifolia ssp. serpyllifoliathyme-leafed spurge 4.3
110EupCroton setigerusdove weed 1.2
111FabAcmispon strigosusstrigose lotus51.1
112FabLathyrus vestitus var. alefeldiiSan Diego pea2 
113FabLupinus bicolordwarf lupine50.3
114FabLupinus concinnusbajada lupine2 
115FabLupinus concinnus ssp. optatusbajada lupine11.0
116FabLupinus excubitus var. austromontanusmountain grape-soda lupine1 
117FabLupinus formosuswestern lupine11.1
118FabTrifolium albopurpureumIndian clover30.3
119FabTrifolium gracilentumpin-point clover30.4
120FabTrifolium variegatumvariegated clover1 
121FagQuercus agrifolia var. agrifoliacoast live oak 0.4
122FagQuercus agrifolia var. oxyadeniasouthern coast live oak2V2.5
123GerErodium botrys*long-beaked filaree 0.4
124GerErodium cicutarium*redstem filaree20.3
125GroRibes quercetorumoak gooseberry2 
126LamMarrubium vulgare*horehound1 
127LamMonardella nanalittle monardella1 
128LamSalvia columbariaechia22.0
129LytLythrum californicumCalifornia loosestrife1 
130MalSidalcea sparsifoliacheckerbloom1 
131MonCalandrinia ciliatared maids30.3
132MonCalyptridium monandrumsand cress30.4
133MonClaytonia parviflora ssp. parvifloranarrow-leaved miner's lettuce21.0
134MonClaytonia perfoliata ssp. mexicanasouthern miner's lettuce1 
135NycBoerhavia coccineascarlet spiderling2 
136NycMirabilis multiflora var. pubescensgiant four o'clock3 
137OleFraxinus velutinavelvet ash 4.5
138OnaCamissonia strigulosastrigose suncup50.4
139OnaCamissoniopsis bistortasouthern suncup1 
140OnaCamissoniopsis confusaSan Bernardino suncup12.4
141OnaCamissoniopsis hirtellafield suncup1 
142OnaCamissoniopsis pallida ssp. pallidapale suncup10.4
143OnaClarkia purpurea ssp. quadrivulnerapurple clarkia1 
144OnaEpilobium brachycarpumautumn willowweed 0.4
145OnaOenothera californica ssp. californicaCalifornia evening-primrose30.6
146OroCastilleja exserta ssp. exsertapurple owl's-clover20.6
147PapEschscholzia californicaCalifornia poppy41.4
148PapPlatystemon californicuscream cups2 
149PlaAntirrhinum coulterianumCoulter's snapdragon1 
150PlaCollinsia concolorsouthern Chinese houses3 
151PlaPenstemon centranthifoliusscarlet bugler11.0
152PlaPenstemon spectabilis var. spectabilisshowy penstemon1 
153PlaPlantago patagonicaPatagonia plantain20.4
154PlaVeronica anagallis-aquatica*water speedwell1 
155PolEriastrum sapphirinum ssp. sapphirinumsapphire woolly-star10.4
156PolGilia angelensisangel's gilia10.4
157PolGilia capitata ssp. abrotanifoliaglobe gilia5 
158PolGilia diegensiscoastal gilia10.4
159PolLeptosiphon liniflorusflax-flowered linanthus22.0
160PolLeptosiphon parvifloruscommon linanthus21.0
161PolLinanthus bigeloviiBigelow's linanthus 0.6
162PolLinanthus dianthiflorusground pink4 
163PolMicrosteris gracilisannual phlox2 
164PolEriogonum davidsoniiDavidson's buckwheat3 
165PolEriogonum elongatum var. elongatumlong-stemmed buckwheat3 
166PolEriogonum fasciculatum var. polifoliumCalifornia buckwheat 0.3
167PolEriogonum gracile var. gracileslender buckwheat11.2
168PolEriogonum gracile var. incultumslender buckwheat20.4
169PolEriogonum wrightii var. membranaceumWright's buckwheat10.4
170PolPolygonum aviculare ssp. depressum*knotweed 0.3
171PolPterostegia drymarioidesthreadstem1 
172PorPortulaca oleracea*common purslane 0.4
173RanRanunculus californicusCalifornia buttercup1 
174RanRanunculus cymbalariaRocky Mountain buttercup2 
175RhaCeanothus cuneatus var. cuneatusbuck brush1 
176RhaCeanothus leucodermischaparral whitethorn11.0
177RhaCeanothus perplexanscupped-leaf ceanothus1 
178RhaFrangula californica ssp. tomentellahoary coffeeberry31.0
179RhaRhamnus ilicifoliahollyleaf redberry11.0
180RosAdenostoma sparsifoliumred shanks4 
181RosCercocarpus betuloides var. betuloidesbirch-leaf mountain-mahogany 1.0
182RosPrunus ilicifolia ssp. ilicifoliahollyleaf cherry 1.0
183RosRubus ursinusCalifornia blackberry1 
184RubGalium andrewsii ssp. andrewsiiphlox-leaved bedstraw2 
185RubGalium aparinecommon bedstraw1 
186SalPopulus fremontii ssp. fremontiiFremont cottonwood 0.4
187SalSalix laevigatared willow 0.4
188ScrScrophularia californicaCalifornia bee plant21.0
189SolDatura wrightiisacred datura 0.3
190SolSolanum umbelliferumblue-witch nightshade1 
191SolSolanum xantipurple nightshade1 
192UrtUrtica dioica ssp. holosericeastinging nettle 0.4
193VisPhoradendron serotinum ssp. tomentosumoak mistletoe1 
194ZygTribulus terrestris*puncture-vine10.4
195AllAllium lacunosumpitted onion1 
196CypCarex praegracilisclustered field sedge1 
197CypEleocharis macrostachyacommon spikerush1 
198CypEleocharis parishiiParish's spikerush1 
199CypScirpus microcarpuspanicled bulrush1 
200JunJuncus macrophylluslong-leaved rush1 
201JunJuncus mexicanusMexican rush1 
202LilCalochortus splendenssplendid mariposa lily1 
203MelToxicoscordion venenosum var. venenosumdeath-camas1 
204PoaAristida purpureapurple three-awn x
205PoaAvena barbata*slender wild oats10.4
206PoaAvena fatua*wild oats 1.0
207PoaBouteloua barbata var. barbatasix-weeks grama 0.4
208PoaBromus diandrus*ripgut brome10.3
209PoaBromus hordeaceus*soft chess1 
210PoaBromus madritensis ssp. rubens*red brome30.3
211PoaBromus tectorum*downy brome20.4
212PoaCynodon dactylon*Bermuda grass 0.4
213PoaEragrostis cilianensis*stinkgrass 0.4
214PoaFestuca microstachysPacific fescue3 
215PoaFestuca myuros*rattail fescue2 
216PoaHordeum marinum ssp. gussoneanum*Mediterranean barley1 
217PoaHordeum murinum*foxtail barley30.4
218PoaPoa secunda ssp. secundaone-sided bluegrass1 
219PoaSchismus barbatus*Mediterranean schismus11.0
220PoaStipa cernuanodding needlegrass1 

Voucher data provided by the participants of the Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/).

Go to:

Copyright © 2014-2015 by Tom Chester, James Dillane, Kate Harper, Adrienne Ballwey, Carla Hoegen, Fred Melgert, Keir Morse, Jim Roberts, and Nancy Accola
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
Last update: 11 April 2015