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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Family Name Distinguishing Characteristics Pteridaceae Cheilanthes covillei leaf margin recurved; leaf surface beady on top, scaly on bottom Pteridaceae Cheilanthes parryi leaf margin recurved; leaf grayish on top, woolly on bottom Pteridaceae Cheilanthes viscida leaf margin recurved; leaf sticky on top Pteridaceae Notholaena californica leaf margin recurved; leaf bottom with white exudate Pteridaceae Pentagramma triangularis ssp. maxonii leaf margin flat; leaf bottom with white exudate; leaf top with yellow stalked glands Pteridaceae Pentagramma triangularis ssp. triangularis leaf margin flat; leaf bottom with yellow exudate; leaf top glabrous Selaginellaceae Selaginella eremophila distinguished from moss by presence of roots Ephedraceae Ephedra aspera 2 leaves / node; seed 1 / cone, surface smooth Ephedraceae Ephedra californica 3 leaves / node, twigs not spiny Ephedraceae Ephedra fasciculata var. clokeyi 2 leaves / node; seed 1 / cone, surface furrowed Ephedraceae Ephedra nevadensis 2 leaves / node; seeds 2 / cone; cone stalked 1-5 mm Ephedraceae Ephedra trifurca 3 leaves / node, twigs spiny Ephedraceae Ephedra viridis 2 leaves / node; seeds 2 / cone; cone sessile or stalked 1-5 mm Acanthaceae Carlowrightia arizonica Similar to Ditaxis lanceolata in gestalt, but leaves opposite Asclepiadaceae Asclepias albicans few-stemmed; 6-12 feet high; lvs 2-3 / node; hoods < anther head Asclepiadaceae Asclepias subulata many-stemmed; 3-6 feet high; lvs 2 / node; hoods >> anther head Asclepiadaceae Matelea parvifolia filament column appendages fused into low structure around anther head Asclepiadaceae Sarcostemma cynanchoides ssp. hartwegii pl sparsely hairy; corolla gen purple; filament column appendages free from ring of tissues at corolla base Asclepiadaceae Sarcostemma hirtellum pl densely hairy; corolla gen greenish white; filament column appendages fused to ring of tissues at corolla base Asteraceae Adenophyllum porophylloides somewhat similar to Porophyllum gracile, but lobed leaves with glands and often with sharp teeth Asteraceae Baccharis sergiloides Similar 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 Asteraceae Baileya multiradiata var. multiradiata rays 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 Asteraceae Baileya pauciradiata rays 4-8, pale yellow; invol gen 4-6 mm diam; heads 2-3 Asteraceae Baileya pleniradiata rays 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 Asteraceae Brickellia arguta var. arguta lvs sharply toothed Asteraceae Brickellia desertorum pl 8-15 dm; lvs ovate; heads 8-12 fl'd, 8-10 mm; minutely tomentose Asteraceae Brickellia frutescens pl 3-6 dm; lvs oblong to spoon-shaped; heads 20-30 fl'd, 13-15 mm, gen 1(3), terminal Asteraceae Calycoseris parryi ligules yellow; tack-shaped glands dark-colored Asteraceae Calycoseris wrightii ligules white; tack-shaped glands pale Asteraceae Chaenactis artemisiifolia lower 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 Asteraceae Chaenactis carphoclinia var. carphoclinia corolla 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 Asteraceae Chaenactis carphoclinia var. peirsonii corolla 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 Asteraceae Chaenactis fremontii corolla white; outer phyllaries sharp, becoming glabrous;lvs entire or 1-pinnately lobed, lobes 1-2(5) pairs, well-separated, longest lobe gen near middle Asteraceae Chaenactis glabriuscula var. glabriuscula corolla yellow Asteraceae Chaenactis stevioides corolla white; outer phyllaries gen blunt, persistently glandular-hairy or cobwebby; largest lf blades entire or 1-2 pinnately lobed, longest lobe gen near middle Asteraceae Chaenactis xantiana lower 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 Asteraceae Chrysothamnus paniculatus like Ericamera brachylepis, but phyllaries ~ 5 ranked in columns, midvein not prominently raised Asteraceae Chrysothamnus teretifolius herbage gland-dotted; corollas yellow; phyllaries strongly vertically ranked, tips swollen, green Asteraceae *Conyza bonariensis midvein of phyllary green to purple, not resin-filled; ligules ~ 0 mm Asteraceae Conyza canadensis midvein of phyllary brown, resin-filled; ligules 0-1 mm Asteraceae Encelia actoni heads solitary; rays present Asteraceae Encelia farinosa heads in panicles; dead heads nodding, minute Asteraceae Encelia frutescens heads solitary; rays absent Asteraceae Ericameria brachylepis lvs thread-like; heads in raceme-like or narrowly panicle-like clusters at ends of leafy branches Asteraceae Ericameria cuneata var. spathulata lvs obovate, 4-16 mm wide Asteraceae Ericameria linearifolia lvs linear; head 1 per stem Asteraceae Eriophyllum multicaule heads ~ sessile, peduncle < 5 mm; ray fls 5-7, ligules ~ 2 mm, yellow Asteraceae Eriophyllum wallacei peduncle 1-3 cm; ray fls 5-10, ligules 3-4 mm, yellow to cream-white Asteraceae Filago arizonica sts spreading, heads in groups of 4-10, restricted to forks and tips of branches; sts gen lfless between lower forks, ~glabrous, purplish to black Asteraceae Filago californica sts ~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 Asteraceae Filago depressa sts ~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 Asteraceae Geraea canescens lvs wing-petioled below, invol 7-12 mm; phyllaries narrowly lanceolate, acute, green ciliate; ray fls 10-21, ligules 1-2 cm Asteraceae Helianthus niveus ssp. canescens central chaff scales tipped with stiff white hairs Asteraceae Helianthus niveus ssp. tephrodes sand dunes; central chaff scales glabrous or very finely appressed-hairy Asteraceae Isocoma acradenia var. acradenia lvs narrowly lanceolate, entire; invols 4-5 mm Asteraceae Isocoma acradenia var. eremophila lvs narrowly obovate, with long-tapering base, to oboate, with 4-6 teeth per side; invols 5-7 mm Asteraceae Malacothrix californica st scapose; lvs gen long-hairy near base Asteraceae Malacothrix glabrata sts leafy, ~branched; basal lvs not long-hairy at base Asteraceae Pectis papposa var. papposa herbage 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 Asteraceae Porophyllum gracile Somewhat similar to Adenophyllum porophylloides, but lvs entire, linear, glaucous Asteraceae Rafinesquia californica ligules 5-8 mm, 3-5 mm beyond phyllaries Asteraceae Rafinesquia neomexicana ligules 15-20 mm, 10+mm beyond phyllaries Asteraceae *Sonchus asper ssp. asper basal lobes of lvs rounded Asteraceae *Sonchus oleraceus basal lobes of lvs acute Asteraceae Stephanomeria exigua ssp. deanei peduncles and invols strongly glandular; frs 2-2.5 mm Asteraceae Stephanomeria exigua ssp. exigua peduncles and invols glabrous to sparsely glandular; frs 2.6-3.2 mm Asteraceae Stylocline gnaphaloides lvs gen obtuse, uppermost < 13 mm, ~elliptic to obovate Asteraceae Stylocline micropoides lvs acute, uppermost gen 11-15 mm, awl-like to lanceolate Asteraceae Trichoptilium incisum gen 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 Asteraceae Viguiera parishii pappus of 2 fringed scales (each 0.5-1.5 mm) and 2-3 lanceolate scales (each 2-3 mm) Boraginaceae Amsinckia menziesii var. intermedia calyx lobes 5; corolla tube 10 veined near base; nutlet surface tubercled, sometimes ridged; corolla 7-11 mm, 4-10 mm wide at top Boraginaceae Amsinckia menziesii var. menziesii calyx lobes 5; corolla tube 10 veined near base; nutlet surface tubercled, sometimes ridged; corolla 4-7 mm, 2-3 mm wide at top Boraginaceae Amsinckia tessellata var. tessellata calyx 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 Boraginaceae Cryptantha angustifolia corolla width 1-5 mm; calyx 1-3.6 mm in fl, 2.5-4 mm in fr; nutlets 4 Boraginaceae Cryptantha barbigera corolla width 1-8 mm; calyx 4-6 mm in fl, 5-10 mm in fr; nutlets 1-4 Boraginaceae Cryptantha costata nutlets 4, sharp-angled; calyx in fl 3-4 mm Boraginaceae Cryptantha decipiens like 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 Boraginaceae Cryptantha ganderi corolla width 1-2 mm; calyx 3-4 mm in fl, 6-10 mm in fr; nutlets 1-2 Boraginaceae Cryptantha holoptera like C. decipiens, but with numerous short ascending branches; nutlets winged < 0.5 mm, wings not lobed Boraginaceae Cryptantha intermedia corolla width 2-8 mm; calyx 2-3.2 mm in fl, 3.5-6 mm in fr; nutlets 1-4 Boraginaceae Cryptantha maritima corolla width 0.5-1.5 mm; calyx 1-2 mm in fl, 2-3.1 mm in fr; nutlets 1-2 Boraginaceae Cryptantha micrantha Plant gen wider than tall; flowers in dense bracted heads; calyx not circumscissile; root purplish Boraginaceae Cryptantha muricata corolla width 1-8 mm; calyx 1-2 mm in fl, 2-4.2 mm in fr; nutlets 4(2-4) Boraginaceae Cryptantha nevadensis corolla width 1-2 mm; calyx 1.8-4 mm in fl, 4-10 mm in fr; nutlets 4 Boraginaceae Cryptantha pterocarya nutlets winged 0.5-1.0 mm, wings lobed Boraginaceae Cryptantha pterocarya var. cycloptera Plant tall, upright; flower appears to float out of a honking calyx, due to the wings on the nutlets Boraginaceae Cryptantha racemosa perennial Chenopodiaceae Atriplex canescens ssp. canescens shrub; fruit 4 winged, 4-25 mm Chenopodiaceae Atriplex lentiformis ssp. lentiformis shrub; fr unwinged, 2-6 mm; lvs entire, ovate to deltate, gen 10-50 mm wide Chenopodiaceae Atriplex polycarpa shrub; fr unwinged, 2-3 mm; lvs entire, oblong, 2-4 mm wide Fabaceae Amorpha fruticosa no glands on leaf rachis Fabaceae Astragalus crotalariae leaves green Hydrophyllaceae Phacelia crenulata var. ambigua like P. pedicellata, but with gray / yellow pollen, and pedicels shorter than calyx Hydrophyllaceae Phacelia crenulata var. minutiflora like P. pedicellata, but with gray / yellow pollen, and pedicels shorter than calyx Hydrophyllaceae Phacelia pedicellata like P. crenulata, but with blue/purple pollen and pedicels at least as long as calyx Krameriaceae Krameria erecta spines barbed along shaft or smooth; flag petals fused at base Krameriaceae Krameria grayi spines barbed only at tip; flag petals free Loasaceae Mentzelia affinis fruit 1 rowed above mid-ovary; seeds prism-like, 3 angled Loasaceae Mentzelia albicaulis fruit 2-3 rowed above mid-ovary; seeds grain-like Rhamnaceae Ziziphus parryi var. parryi Similar in habit to Prunus fremontii, but leaf elliptic to obovate, margin ~entire; fr glabrous; petals yellow Rosaceae Prunus fremontii Similar in habit to Ziziphus parryi, but leaf ovate to round, crenulate to serrate (you "prunus with a saw"), fruit puberulent; petals white Typhaceae Typha domingensis pistillate stalks peg-like, not hair-like
Copyright © 2009 by Tom Chester.
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Updated 20 November 2009.