Cirsium scariosum var. thorneae

S. L. Welsh

Great Basin Naturalist 42: 201. 1982.

Common names: Thorne’s thistle
Endemic
Treatment appears in FNA Volume 19. Treatment on page 157. Mentioned on page 154, 155, 156, 158.

Plants erect, caulescent (rarely nearly acaulescent), 20–130 cm. Stems distally short-branched to openly much-branched throughout, leafy, glabrous or villous with septate trichomes. Leaves: blades oblong, oblanceolate, or narrowly elliptic, usually pinnately lobed more than halfway to midveins, abaxial faces glabrous or gray-tomentose, adaxial glabrous; distal usually deeply divided, fiercely armed with stout spines, the longer 1–3 cm. Heads 1–10+, sessile or pedunculate, solitary or crowded near tip of main-stem or branches, usually subtended and ± overtopped by distal leaves. Involucres (broadly ovoid to hemispheric) 2.5–3.5 cm. Phyllaries: outer and mid lanceolate to narrowly ovate, spines slender to stout, 2–8 mm; apices of inner usually abruptly expanded into scarious, erose-toothed appendages. Corollas white to dull purple, 29–34 mm, tubes 14–18 mm, throats 6.5–9 mm, lobes 7–8.5 mm; style tips 5–6.5 mm. Cypselae 4.5–5 mm; pappi 20–27 mm.


Phenology: Flowering summer (Jun–Sep).
Habitat: Meadows, streamsides, valley bottoms, often in saline soils
Elevation: 1500–2200 m

Discussion

Variety thorneae grows mostly in the Basin and Range province of Utah with populations in eastern Nevada, southern Idaho, and western Colorado.

Selected References

None.

Lower Taxa

None.

"fine" is not a number."narrower" is not a number.

gray-tomentose +  and glabrous +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
expanded +
scarious +
erose-toothed +
subcapitate +, racemiform +  and spiciform +
indeterminate +  and determinate +
David J. Keil +
S. L. Welsh +
winged-petiolate +  and sessile +
decurrent +
Asteraceae tribe Cynareae +
compound +  and simple +
linear to elliptic +
5 cm50 mm <br />0.05 m <br /> (20 cm200 mm <br />0.2 m <br />) +
lobed;elliptic;oblanceolate;elliptic;oblanceolate;oblong +
3cm;7cm +
10-nerved or 20-nerved +  and rugose +
tawny +  and white +
Thorne’s thistle +
actinomorphic +
white +  and dull purple +
2.9 cm29 mm <br />0.029 m <br /> (3.4 cm34 mm <br />0.034 m <br />) +
light +  and dark-brown +
compressed +  and ovoid +
fertile +  and bisexual +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Colo. +, Idaho +, Nev. +  and Utah. +
1500–2200 m +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Meadows, streamsides, valley bottoms, often in saline soils +
pedunculate +  and sessile +
crowded +  and solitary +
indeterminate +
each +  and sessile +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
glabrate +  and arachnoid +
ovoid;hemispheric +
2.5 cm25 mm <br />0.025 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (6 cm60 mm <br />0.06 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
lobed +, spinose-dentate +, linear-lanceolate +  and broadly triangular +
0.2 cm2 mm <br />0.002 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
entire +  and dentate +
scarious-fringed +  and entire +
rounded +
2-carpellate +
white +  and tan +
persistent +
2 cm20 mm <br />0.02 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
0 cm0 mm <br />0 m <br /> (10 cm100 mm <br />0.1 m <br />) +
Flowering summer (Jun–Sep). +
middle +  and outer +
weakly to strongly +
short-caulescent +  and acaulescent +
papillate +  and smooth +
Great Basin Naturalist +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
erect +  and spreading +
flattened +
Slender (?) +  and Stout (?) +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
leafy +, distally short-branched +  and openly much-branched +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.5 cm5 mm <br />0.005 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
Cirsium hookerianum var. scariosum +
Cirsium scariosum var. thorneae +
Cirsium scariosum +
variety +
cylindric +
expanded +
0.65 cm6.5 mm <br />0.0065 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
tipped +  and spineless +
scabro-denticulate +  and narrowed +
expanded +
bristly-dentate to coarsely +
slender +
1.4 cm14 mm <br />0.014 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
taprooted +, caulescent +  and acaulescent +
perennial +  and biennial +
0 cm0 mm <br />0 m <br /> (200 cm2,000 mm <br />2 m <br />) +