Xylorhiza tortifolia var. imberbis

(Cronquist) T. J. Watson

Brittonia 29: 211. 1977.

Common names: Smooth Mojave woody-aster
Endemic
Basionym: Machaeranthera tortifolia var. imberbis Cronquist Leafl. W. Bot. 10: 12. 1963
Treatment appears in FNA Volume 20. Treatment on page 409. Mentioned on page 408.

Stems, leaves, and involucres glabrous, stipitate-glandular. Leaf margins sparsely piloso-villous to puberulent. 2n = 12.


Phenology: Flowering Apr–May(–Jun).
Habitat: Sandy or gravelly slopes and flats, in pinyon-juniper, sagebrush, and blackbrush zones
Elevation: 600–1900 m

Discussion

The geographic distribution of var. imberbis usually follows the canyons of the Colorado River of Utah and adjacent Arizona at least to Toroweap Point; it also occurs in Clark and Nye counties, Nevada, where it intergrades with var. tortifolia (A. Cronquist 1994).

Selected References

None.

Lower Taxa

None.
stipitate-glandular +, sparsely tomentose +  and villous +
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
spiciform +, racemiform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
Guy L. Nesom +
(Cronquist) T. J. Watson +
subclasping +
attenuate +
Machaeranthera tortifolia var. imberbis +
linear;lanceolate or oblanceolate oblong or narrowly elliptic +
rugulose +  and muricate +
Smooth Mojave woody-aster +
not 2-lipped +  and actinomorphic +
fusiform +  and linear or ovoid more or less compressed +
fertile +  and bisexual +
fertile +  and bisexual +
Ariz. +, Nev. +  and Utah. +
600–1900 m +
stipitate-glandular +, glabrous +  and villous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Sandy or gravelly slopes and flats, in pinyon-juniper, sagebrush, and blackbrush zones +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1.2 cm12 mm <br />0.012 m <br /> (2 cm20 mm <br />0.02 m <br />) +
stipitate-glandular +  and glabrous +
campanulate;hemispheric +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
lanceolate;elliptic-oblong or oblanceolate +
subpetiolate +  and sessile +
stipitate-glandular +  and glabrous +
triangular +
dentate-spinulose +  and entire +
spinulose-toothed +
2-carpellate +
persistent +
5 cm50 mm <br />0.05 m <br /> (25 cm250 mm <br />0.25 m <br />) +
Flowering Apr–May(–Jun). +
lanceolate +
bearing subulate enations +, hairy +  and bristly +
concave;usually flat;conic +
exalbuminous +
stipitate-glandular +  and glabrous +
appendaged +  and truncate +
papillate +  and smooth +
Machaeranthera tortifolia +
Xylorhiza tortifolia var. imberbis +
Xylorhiza tortifolia +
variety +
shorter to longer +
60 cm600 mm <br />0.6 m <br /> (80 cm800 mm <br />0.8 m <br />) +