Plant Species of the Borrego Desert: Distinguishing Characteristics of Similar Species

This is a start of a list giving tips on how to distinguish species that are similar. Significantly more species need to be added.

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FamilyNameDistinguishing Characteristics
PteridaceaeCheilanthes covilleileaf margin recurved; leaf surface beady on top, scaly on bottom
PteridaceaeCheilanthes parryileaf margin recurved; leaf grayish on top, woolly on bottom
PteridaceaeCheilanthes viscidaleaf margin recurved; leaf sticky on top
PteridaceaeNotholaena californicaleaf margin recurved; leaf bottom with white exudate
PteridaceaePentagramma triangularis ssp. maxoniileaf margin flat; leaf bottom with white exudate; leaf top with yellow stalked glands
PteridaceaePentagramma triangularis ssp. triangularisleaf margin flat; leaf bottom with yellow exudate; leaf top glabrous
SelaginellaceaeSelaginella eremophiladistinguished from moss by presence of roots
EphedraceaeEphedra aspera2 leaves / node; seed 1 / cone, surface smooth
EphedraceaeEphedra californica3 leaves / node, twigs not spiny
EphedraceaeEphedra fasciculata var. clokeyi2 leaves / node; seed 1 / cone, surface furrowed
EphedraceaeEphedra nevadensis2 leaves / node; seeds 2 / cone; cone stalked 1-5 mm
EphedraceaeEphedra trifurca3 leaves / node, twigs spiny
EphedraceaeEphedra viridis2 leaves / node; seeds 2 / cone; cone sessile or stalked 1-5 mm
AcanthaceaeCarlowrightia arizonicaSimilar to Ditaxis lanceolata in gestalt, but leaves opposite
AsclepiadaceaeAsclepias albicansfew-stemmed; 6-12 feet high; lvs 2-3 / node; hoods < anther head
AsclepiadaceaeAsclepias subulatamany-stemmed; 3-6 feet high; lvs 2 / node; hoods >> anther head
AsclepiadaceaeMatelea parvifoliafilament column appendages fused into low structure around anther head
AsclepiadaceaeSarcostemma cynanchoides ssp. hartwegiipl sparsely hairy; corolla gen purple; filament column appendages free from ring of tissues at corolla base
AsclepiadaceaeSarcostemma hirtellumpl densely hairy; corolla gen greenish white; filament column appendages fused to ring of tissues at corolla base
AsteraceaeAdenophyllum porophylloidessomewhat similar to Porophyllum gracile, but lobed leaves with glands and often with sharp teeth
AsteraceaeBaccharis sergiloidesSimilar to B. sarothroides, but pistillate pappus very short, 1-3 mm in fr; and larger lvs obovate. B. sarothroides has pappus 7-11 mm, and larger lvs linear
AsteraceaeBaileya multiradiata var. multiradiatarays 15-many, bright yellow; invol 10+ mm diam; heads 1; ligules 10-20 mm, widely linear or oblong, prominently 3-lobed; peduncles gen 10-20+ cm, ~scape-like
AsteraceaeBaileya pauciradiatarays 4-8, pale yellow; invol gen 4-6 mm diam; heads 2-3
AsteraceaeBaileya pleniradiatarays 15-many, bright yellow; invol 10+ mm diam; heads 1; ligules 6-10 mm, widely elliptic to obovate, shallowly 3-lobed to truncate; peduncles gen 3-10 cm, gen leafy-bracted
AsteraceaeBrickellia arguta var. argutalvs sharply toothed
AsteraceaeBrickellia desertorumpl 8-15 dm; lvs ovate; heads 8-12 fl'd, 8-10 mm; minutely tomentose
AsteraceaeBrickellia frutescenspl 3-6 dm; lvs oblong to spoon-shaped; heads 20-30 fl'd, 13-15 mm, gen 1(3), terminal
AsteraceaeCalycoseris parryiligules yellow; tack-shaped glands dark-colored
AsteraceaeCalycoseris wrightiiligules white; tack-shaped glands pale
AsteraceaeChaenactis artemisiifolialower sts and lvs whitish granular-puberulent; largest lf blades (2)3-4 pinnately lobed, longest lobe near base; tips of longest phyllaries sharp but not acuminate, ~flat, green; lf tips flat; pappus 0
AsteraceaeChaenactis carphoclinia var. carphocliniacorolla white; tips of longest phyllaries acuminate, needle-like, cylindric, gen reddish;largest lf blades (2)3-4 pinnately lobed, longest lobe near base, bases of petioles not strongly enlarged; lvs basal and cauline, < 7 cm; bases of petioles not strongly enlarged
AsteraceaeChaenactis carphoclinia var. peirsoniicorolla white; tips of longest phyllaries acuminate, needle-like, cylindric, gen reddish;largest lf blades (2)3-4 pinnately lobed, longest lobe near base, bases of petioles not strongly enlarged; lvs gen basal, longest 7-10 cm; bases of petioles strongly enlarged; RARE, east base of SnRsMtns
AsteraceaeChaenactis fremontiicorolla white; outer phyllaries sharp, becoming glabrous;lvs entire or 1-pinnately lobed, lobes 1-2(5) pairs, well-separated, longest lobe gen near middle
AsteraceaeChaenactis glabriuscula var. glabriusculacorolla yellow
AsteraceaeChaenactis stevioidescorolla white; outer phyllaries gen blunt, persistently glandular-hairy or cobwebby; largest lf blades entire or 1-2 pinnately lobed, longest lobe gen near middle
AsteraceaeChaenactis xantianalower sts and lvs glabrous or +-cobwebby; largest lf blades entire or 1-2 pinnately lobed, longest lobe gen near middle; corolla white, longest phyllaries 10-18 mm, bases glabrous, tips densely puberulent; corollas radial; peduncles not glandular
AsteraceaeChrysothamnus paniculatuslike Ericamera brachylepis, but phyllaries ~ 5 ranked in columns, midvein not prominently raised
AsteraceaeChrysothamnus teretifoliusherbage gland-dotted; corollas yellow; phyllaries strongly vertically ranked, tips swollen, green
Asteraceae*Conyza bonariensismidvein of phyllary green to purple, not resin-filled; ligules ~ 0 mm
AsteraceaeConyza canadensismidvein of phyllary brown, resin-filled; ligules 0-1 mm
AsteraceaeEncelia actoniheads solitary; rays present
AsteraceaeEncelia farinosaheads in panicles; dead heads nodding, minute
AsteraceaeEncelia frutescensheads solitary; rays absent
AsteraceaeEricameria brachylepislvs thread-like; heads in raceme-like or narrowly panicle-like clusters at ends of leafy branches
AsteraceaeEricameria cuneata var. spathulatalvs obovate, 4-16 mm wide
AsteraceaeEricameria linearifolialvs linear; head 1 per stem
AsteraceaeEriophyllum multicauleheads ~ sessile, peduncle < 5 mm; ray fls 5-7, ligules ~ 2 mm, yellow
AsteraceaeEriophyllum wallaceipeduncle 1-3 cm; ray fls 5-10, ligules 3-4 mm, yellow to cream-white
AsteraceaeFilago arizonicasts spreading, heads in groups of 4-10, restricted to forks and tips of branches; sts gen lfless between lower forks, ~glabrous, purplish to black
AsteraceaeFilago californicasts ~erect, not forked, central axis dominant; heads in groups of 1-4, not restricted to forks and branch tips; sts ~evenly leafy between lower forks, cobwebby, grayish to greenish; lvs gen oblanceolate, acute
AsteraceaeFilago depressasts ~spreading, forked, central axis not dominant; heads in groups of 1-4, not restricted to forks and branch tips; sts ~evenly leafy between lower forks, cobwebby, grayish to greenish; lvs gen elliptic to obovate, obtuse
AsteraceaeGeraea canescenslvs wing-petioled below, invol 7-12 mm; phyllaries narrowly lanceolate, acute, green ciliate; ray fls 10-21, ligules 1-2 cm
AsteraceaeHelianthus niveus ssp. canescenscentral chaff scales tipped with stiff white hairs
AsteraceaeHelianthus niveus ssp. tephrodessand dunes; central chaff scales glabrous or very finely appressed-hairy
AsteraceaeIsocoma acradenia var. acradenialvs narrowly lanceolate, entire; invols 4-5 mm
AsteraceaeIsocoma acradenia var. eremophilalvs narrowly obovate, with long-tapering base, to oboate, with 4-6 teeth per side; invols 5-7 mm
AsteraceaeMalacothrix californicast scapose; lvs gen long-hairy near base
AsteraceaeMalacothrix glabratasts leafy, ~branched; basal lvs not long-hairy at base
AsteraceaePectis papposa var. papposaherbage spicy-scented; mound-shaped; lvs narrowly linear, gland-dotted on margins; phyllaries 8, linear, each with subterminal gland and several smaller submarginal glands; rays 8; corollas 3-6 mm
AsteraceaePorophyllum gracileSomewhat similar to Adenophyllum porophylloides, but lvs entire, linear, glaucous
AsteraceaeRafinesquia californicaligules 5-8 mm, 3-5 mm beyond phyllaries
AsteraceaeRafinesquia neomexicanaligules 15-20 mm, 10+mm beyond phyllaries
Asteraceae*Sonchus asper ssp. asperbasal lobes of lvs rounded
Asteraceae*Sonchus oleraceusbasal lobes of lvs acute
AsteraceaeStephanomeria exigua ssp. deaneipeduncles and invols strongly glandular; frs 2-2.5 mm
AsteraceaeStephanomeria exigua ssp. exiguapeduncles and invols glabrous to sparsely glandular; frs 2.6-3.2 mm
AsteraceaeStylocline gnaphaloideslvs gen obtuse, uppermost < 13 mm, ~elliptic to obovate
AsteraceaeStylocline micropoideslvs acute, uppermost gen 11-15 mm, awl-like to lanceolate
AsteraceaeTrichoptilium incisumgen tomentose or white-woolly; lvs mostly clustered in lower half, 1-3 cm; heads discoid, solitary; phyllaries in 2 ~equal series, free, 5-7 mm; pappus of 5 scales, each 5-7 mm, dissected into many bristles
AsteraceaeViguiera parishiipappus of 2 fringed scales (each 0.5-1.5 mm) and 2-3 lanceolate scales (each 2-3 mm)
BoraginaceaeAmsinckia menziesii var. intermediacalyx lobes 5; corolla tube 10 veined near base; nutlet surface tubercled, sometimes ridged; corolla 7-11 mm, 4-10 mm wide at top
BoraginaceaeAmsinckia menziesii var. menziesiicalyx lobes 5; corolla tube 10 veined near base; nutlet surface tubercled, sometimes ridged; corolla 4-7 mm, 2-3 mm wide at top
BoraginaceaeAmsinckia tessellata var. tessellatacalyx lobes 2-4; corolla tube 20 veined near base; nutlet surface cobblestone-like or round-tubercled, ridged or not; corolla 8-12 mm, 2-6 mm wide at top
BoraginaceaeCryptantha angustifoliacorolla width 1-5 mm; calyx 1-3.6 mm in fl, 2.5-4 mm in fr; nutlets 4
BoraginaceaeCryptantha barbigeracorolla width 1-8 mm; calyx 4-6 mm in fl, 5-10 mm in fr; nutlets 1-4
BoraginaceaeCryptantha costatanutlets 4, sharp-angled; calyx in fl 3-4 mm
BoraginaceaeCryptantha decipienslike C. holoptera, but with spikes mostly in 2's; corolla width 1-5 mm; calyx 1.5-2.5 mm in fl, 2-4 mm in fr; nutlets 1-2
BoraginaceaeCryptantha gandericorolla width 1-2 mm; calyx 3-4 mm in fl, 6-10 mm in fr; nutlets 1-2
BoraginaceaeCryptantha holopteralike C. decipiens, but with numerous short ascending branches; nutlets winged < 0.5 mm, wings not lobed
BoraginaceaeCryptantha intermediacorolla width 2-8 mm; calyx 2-3.2 mm in fl, 3.5-6 mm in fr; nutlets 1-4
BoraginaceaeCryptantha maritimacorolla width 0.5-1.5 mm; calyx 1-2 mm in fl, 2-3.1 mm in fr; nutlets 1-2
BoraginaceaeCryptantha micranthaPlant gen wider than tall; flowers in dense bracted heads; calyx not circumscissile; root purplish
BoraginaceaeCryptantha muricatacorolla width 1-8 mm; calyx 1-2 mm in fl, 2-4.2 mm in fr; nutlets 4(2-4)
BoraginaceaeCryptantha nevadensiscorolla width 1-2 mm; calyx 1.8-4 mm in fl, 4-10 mm in fr; nutlets 4
BoraginaceaeCryptantha pterocaryanutlets winged 0.5-1.0 mm, wings lobed
BoraginaceaeCryptantha pterocarya var. cyclopteraPlant tall, upright; flower appears to float out of a honking calyx, due to the wings on the nutlets
BoraginaceaeCryptantha racemosaperennial
ChenopodiaceaeAtriplex canescens ssp. canescensshrub; fruit 4 winged, 4-25 mm
ChenopodiaceaeAtriplex lentiformis ssp. lentiformisshrub; fr unwinged, 2-6 mm; lvs entire, ovate to deltate, gen 10-50 mm wide
ChenopodiaceaeAtriplex polycarpashrub; fr unwinged, 2-3 mm; lvs entire, oblong, 2-4 mm wide
FabaceaeAmorpha fruticosano glands on leaf rachis
FabaceaeAstragalus crotalariaeleaves green
HydrophyllaceaePhacelia crenulata var. ambigualike P. pedicellata, but with gray / yellow pollen, and pedicels shorter than calyx
HydrophyllaceaePhacelia crenulata var. minutifloralike P. pedicellata, but with gray / yellow pollen, and pedicels shorter than calyx
HydrophyllaceaePhacelia pedicellatalike P. crenulata, but with blue/purple pollen and pedicels at least as long as calyx
KrameriaceaeKrameria erectaspines barbed along shaft or smooth; flag petals fused at base
KrameriaceaeKrameria grayispines barbed only at tip; flag petals free
LoasaceaeMentzelia affinisfruit 1 rowed above mid-ovary; seeds prism-like, 3 angled
LoasaceaeMentzelia albicaulisfruit 2-3 rowed above mid-ovary; seeds grain-like
RhamnaceaeZiziphus parryi var. parryiSimilar in habit to Prunus fremontii, but leaf elliptic to obovate, margin ~entire; fr glabrous; petals yellow
RosaceaePrunus fremontiiSimilar in habit to Ziziphus parryi, but leaf ovate to round, crenulate to serrate (you "prunus with a saw"), fruit puberulent; petals white
TyphaceaeTypha domingensispistillate stalks peg-like, not hair-like


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Copyright © 2009 by Tom Chester.
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Comments and feedback: Tom Chester
Updated 20 November 2009.