Purshia tridentata

(Pursh) de Candolle

Trans. Linn. Soc. London 12: 158. 1818.

Common names: Bitterbrush
Illustrated
Basionym: Tigarea tridentata Pursh Fl. Amer. Sept. 1: 333, plate 15. 1813
Treatment appears in FNA Volume 9. Treatment on page 340. Mentioned on page 339, 341.

Shrubs, evergreen or partially summer–winter-deciduous, 2–25 (–40) dm. Stems: young-stem internodes 4–12 mm, sparsely to densely arachnoid-villous, ± hirtellous, or glabrous, stipitate-glandular or not; short-shoot spurs simple or branched, 5–20 (–60) × 1.5–2 mm. Leaves: blade of 1 or 2 types: (1) persistent, dark green adaxially, obovate to spatulate, 4–9 × (1–) 3–6 mm, irregularly lobed in distal 1/3, lobes 3 (–5), lobes entire, ± terete, central lobe deflexed, often apiculate, 2 lateral ascending, margins strongly revolute, abaxial surface arachnoid-villous, midvein glabrous, glabrate, or hirtellous, adaxial glabrous, sometimes arachnoid-villous or hirtellous, often glandular-punctate along margins; (2) winter deciduous, green-gray adaxially, flabelliform, 6–15+ × 3–7+ mm, margins weakly revolute, usually 3-toothed, sometimes 3-lobed, distally, abaxial surface arachnoid-villous to arachnoid-tomentose, veins ± glabrate, adaxial hirtellous and ± arachnoid villous, sometimes sessile or stipitate-glandular along margins. Pedicels 0.2–2.5 mm. Flowers: hypanthium obconic, 2.5–5 × 1.5–3 mm, 3.5–6 mm diam. in fruit, pubescent-sericeous, sessile or stipitate-glandular; petals usually lemon to cream-yellow, sometimes nearly white, obovate-spatulate, 4–7+ mm; stamens 17–35; carpels 1 or 2. Achenes broadly obovoid-fusiform (circular in cross-section or flattened on common side when paired), 7–12 × 3.5–5.2 mm, 15–22-veined, persistent style 5–7 (–10) mm, densely hirtellous.

Distribution

V9 557-distribution-map.jpg

B.C., Ariz., Calif., Colo., Idaho, Mont., N.Mex., Nebr., Nev., Oreg., Utah, Wash., Wyo., nw Mexico

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Leaves dimorphic, blades flabelliform, thin, margins weakly revolute, usually 3-toothed, sometimes 3-lobed, apically, adaxial surfaces persistently arachnoid-villous and hirtellous, margins rarely with sessile or stipitate glands, these not strongly resinous, (at least proximalmost short-shoot leaves, smaller, thick, 3-lobed distally, margins with or without resinous glands); stems: young long shoots arachnoid-villous to pubescent, stipitate-glandular or not. Purshia tridentata var. tridentata
1 Leaves monomorphic, blades obovate, coriaceous-thickened, 3(–5)-lobed, lobes oblong-linear, central lobes deflexed, 2 lateral ascending, margins strongly revolute, adaxial surfaces glabrous, sometimes weakly arachnoid-villous or hirtellous, margins often with large, resiniferous, punctate glands; stems: young long shoots glabrous or sparsely hirtellous, often stipitate-glandular. Purshia tridentata var. glandulosa
... more about "Purshia tridentata"
arachnoid-villous +  and arachnoid-tomentose +
0.7 cm7 mm <br />0.007 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
obovoid-fusiform +
3.5mm +  and 5.2mm +
stipitate-glandular +, villous +, arachnoid +, hirtellous +, arachnoid-villous +  and glabrous +
James Henrickson +
(Pursh) de Candolle +
gray +  and cinnamon brown +
weathering +
compound +  and simple +
opposite +  and alternate +
cuneate +  and clawed +
Tigarea tridentata +
1.5 cm15 mm <br />0.015 m <br /> (1.9 cm19 mm <br />0.019 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
persistent +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
lobed +, obovate +  and spatulate +
0.3 cm3 mm <br />0.003 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
3mm +  and 6mm +
free +  and distinct +
ascending +  and deflexed +
Bitterbrush +
B.C. +, Ariz. +, Calif. +, Colo. +, Idaho +, Mont. +, N.Mex. +, Nebr. +, Nev. +, Oreg. +, Utah +, Wash. +, Wyo. +  and nw Mexico +
not +  and aggregated +
nectariferous +
glabrous +, not +, stipitate-glandular +  and villous +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
oblanceoloid +  and obovoid-fusiform +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
stipitate-glandular +  and pubescent-sericeous +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
crassinucellate +
green-gray +
deciduous +
6mm +  and 15mm +
immature +  and abscising +
flabelliform +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
3-lobed +  and 3-toothed +
hirtellous +, glabrate +  and glabrous +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0 (?) +  and 4 (?) +
free +  and distinct +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
adnate +, free +, connate +  and distinct +
Trans. Linn. Soc. London +
not arillate +
persistent +
free +  and distinct +
spreading-reflexing +  and spreading-reflexed +
ovate +  and oblong-ovate +
branched +  and simple +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Illustrated +
free +  and distinct +
3 +  and 20 +
adnate +  and free +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
persistent +
distinct +
basal +, lateral +, subterminal +  and terminal +
elongate +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Cowania +
Purshia tridentata +
species +
inconspicuous +
hemispheric +
summer-winter-deciduous +  and evergreen +
not +, stipitate-glandular +, glabrous +, hirtellous +  and arachnoid-villous +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +