Prenanthes boottii

(de Candolle) D. Dietrich

Syn. Pl. 4: 1309. 1847.

Common names: Boot’s rattlesnakeroot
EndemicConservation concern
Basionym: Nabalus bootii de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 241. 1838
Treatment appears in FNA Volume 19. Treatment on page 268. Mentioned on page 264, 265.

Plants 5–25 cm; taproots short, thick, tuberous. Stems decumbent to erect, mottled purple, simple, glabrous proximally, tomentulose distally. Leaves: proximal present at flowering; petiolate (petioles 2–8 cm, not winged); blades ovate to deltate, 2–8 × 0.5–3 cm, bases hastate or sagittate, margins entire or weakly dentate, faces glabrous; distal reduced, elliptic to lanceolate. Heads (10–20) in narrow, racemiform to thyrsiform arrays (nodding). Calyculi of 4–5, dark green to blackish, subulate bractlets 2–5 mm, glabrous. Involucres cylindro-campanulate, 10–11 × 5–6 mm. Phyllaries 8–11, dark green to almost black, lanceolate to subulate, 8–12 mm, faces glabrous. Florets 9–20; corollas white, 7–13 mm. Cypselae light tan to yellow, subcylindric, subterete to angled, 5–6 mm, indistinctly 7–10-ribbed; pappi pale-yellow, 6–8 mm. 2n = 32.


Phenology: Flowering Jul–Aug.
Habitat: Alpine areas above treeline, mountains
Elevation: 1500–2000 m

Discussion

Of conservation concern.

Prenanthes bootii is recognized by its relatively short, decumbent habit, deltate to hastate proximal leaves, entire or weakly dentate margins, glabrous and blackish green phyllaries, white corollas, and alpine habitat.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Prenanthes boottii"
not beaked +  and truncate +
scarious +
ovate +  and lanceolate +
racemiform +  and thyrsiform +
indeterminate +  and determinate +
David J. Bogler +
(de Candolle) D. Dietrich +
sagittate +  and hastate +
Nabalus bootii +
compound +  and simple +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
ovate;deltate +
0.5 cm5 mm <br />0.005 m <br /> (3 cm30 mm <br />0.03 m <br />) +
tuberculate +, rugose +, muricate +  and smooth +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
filiform +
Boot’s rattlesnakeroot +
zygomorphic +, actinomorphic +  and (3-)5-merous +
0.7 cm7 mm <br />0.007 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
light tan +  and yellow +
subterete +  and angled +
elliptic +  and lanceolate +
Maine +, N.H. +, N.Y. +  and Vt. +
1500–2000 m +
winged +  and beaked +
dispersed +
Alpine areas above treeline, mountains +
indeterminate +
each +  and sessile +
0.2 cm2 mm <br />0.002 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
1 cm10 mm <br />0.01 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
cylindro-campanulate +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
cauline +  and basal +
dentate +  and entire +
2-carpellate +
pale-yellow +
persistent +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
Flowering Jul–Aug. +
connate +  and distinct +
8 +  and 11 +
subequal +  and unequal +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
exalbuminous +
Endemic +  and Conservation concern +
mottled purple +
decumbent +  and erect +
tomentulose +  and glabrous +
1 +  and 5 +
appendaged +  and truncate +
papillate +
Undefined tribe Lactuceae +
Prenanthes boottii +
Prenanthes +
species +
dentate +, serrate +  and entire +
5 cm50 mm <br />0.05 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +