Purshia tridentata var. glandulosa

(Curran) M. E. Jones

Proc. Calif. Acad. Sci., ser. 2, 5: 680. 1895.

Common names: Desert bitterbrush
Basionym: Purshia glandulosa Curran Bull. Calif. Acad. Sci. 1: 153. 1885
Treatment appears in FNA Volume 9. Treatment on page 341. Mentioned on page 340.

Stems: young long-shoots glabrous or sparsely hirtellous, often stipitate-glandular. Leaves monomorphic, both long and short-shoot leaves winter persistent; blade obovate to spatulate (when small), coriaceous-thickened, 3 (–5) -lobed, lobes oblong-linear, narrow, central lobe deflexed, 2 lateral ascending, margins strongly revolute, often with large, resiniferous, punctate glands, abaxial surface arachnoid-villous, midvein glabrous, glabrate, or hirtellous, adaxial glabrous, sometimes weakly arachnoid-villous (this often obscured by broad, glabrous midvein in dried leaves) or hirtellous. 2n = 18.


Phenology: Flowering Apr–May.
Habitat: Juniper-pinyon, Joshua tree woodlands, desert blackbrush scrub, chaparral at desert margins
Elevation: (600–)800–1500 m

Distribution

V9 559-distribution-map.jpg

Ariz., Calif., Nev., Utah, Mexico (Baja California)

Discussion

Variety glandulosa is a derivative of var. tridentata. Some sterile specimens of var. glandulosa cannot be distinguished from Purshia stansburyana; both taxa sometimes have similar leaves, and hirtellous, more or less stipitate-glandular young stems.

G. L. Stebbins (1959) and H. C. Stutz and L. K. Thomas (1963) hypothesized that var. glandulosa is a product of hybridization and introgression between Purshia tridentata and P. stansburyana. Although introgression would explain certain similarities, P. tridentata stands as a distinct species strongly differentiated by ovary-fruit characteristics and dimorphic leaves, which allow it to adapt to a wide range of habitats. Hybrids with P. stansburyana are discussed under the latter species.

Selected References

None.

Lower Taxa

None.
arachnoid-villous +
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 +
hirtellous +, arachnoid-villous +  and glabrous +
James Henrickson +
(Curran) M. E. Jones +
gray +  and cinnamon brown +
weathering +
compound +  and simple +
opposite +  and alternate +
cuneate +  and clawed +
Purshia glandulosa +
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 />) +
3(-5)-lobed +, obovate +  and spatulate +
coriaceous-thickened +
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 +
Desert bitterbrush +
Ariz. +, Calif. +, Nev. +, Utah +  and Mexico (Baja California) +
not +  and aggregated +
(600–)800–1500 m +
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 />) +
resiniferous +
Juniper-pinyon, Joshua tree woodlands, desert blackbrush scrub, chaparral at desert margins +
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 +
monomorphic +
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 />) +
Flowering Apr–May. +
adnate +, free +, connate +  and distinct +
Proc. Calif. Acad. Sci., ser. +
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 var. glandulosa +
Purshia tridentata +
variety +
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 />) +