Prenanthes roanensis

(Chickering) Chickering

Bot. Gaz. 6: 191. 1881.

Common names: Roan Mountain rattlesnakeroot
EndemicConservation concern
Basionym: Nabalus roanensis Chickering Bot. Gaz. 5: 155. 1880
Synonyms: Prenanthes cylindrica (Small) E. L. Braun
Treatment appears in FNA Volume 19. Treatment on page 270. Mentioned on page 265.

Plants 18–150 cm; taproots slender or short and thickened, tuberous. Stems erect, green or purple, simple, glabrous proximally, crisply tomentulose distally. Leaves: proximal present at flowering; petiolate (petioles not winged or distal narrowly winged); blades ovate, 3–22 × 2–15 cm, coriaceous, bases cordate to truncate or rounded, margins often deeply 3–5-palmately lobed or compound, lobes and sinuses angular, ultimate margins irregularly dentate, apices acute, faces usually finely tomentulose on veins; mid cauline short-petiolate or sessile; distal short-petiolate or sessile, reduced, lanceolate. Heads in narrowly paniculiform or thyrsiform arrays (nodding). Involucres cylindric to narrowly campanulate, 12–14 × 2.5–3 mm. Calyculi of 4–6, blackish green, triangular to lanceolate bractlets 1–3 mm, densely setose. Phyllaries 5–9, green or dark green, apices blackish, linear to oblanceolate, 9–11 mm, sparsely and coarsely setose. Florets 5–7 (–13); corollas greenish yellow, 8–10 mm. Cypselae tan to yellow, fusiform, subterete or angled, 4–5 mm, indistinctly 8–12-ribbed; pappi yellow to whitish, 5–6 mm. 2n = 16.


Phenology: Flowering Aug–Sep.
Habitat: Spruce-hardwood forests, wooded slopes, open grassy summits
Elevation: 1600–1700 m

Discussion

Of conservation concern.

Prenanthes roanensis is recognized by its 5–7 florets and dark setae on the phyllaries. It is found at mid to high elevations in the Blue Ridge Province of the Appalachian Mountains. It is rather variable and often confused with other species. It is considered rare or threatened throughout its range.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Prenanthes roanensis"
not beaked +  and truncate +
linear;oblanceolate +
0.9 cm9 mm <br />0.009 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
scarious +
ovate +  and lanceolate +
thyrsiform +  and paniculiform +
indeterminate +  and determinate +
David J. Bogler +
(Chickering) Chickering +
cordate +  and truncate or rounded +
Nabalus roanensis +
compound +  and simple +
3 cm30 mm <br />0.03 m <br /> (22 cm220 mm <br />0.22 m <br />) +
coriaceous +
2 cm20 mm <br />0.02 m <br /> (15 cm150 mm <br />0.15 m <br />) +
tuberculate +, rugose +, muricate +  and smooth +
triangular;linear-lanceolate or subulate +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
filiform +
Roan Mountain rattlesnakeroot +
zygomorphic +, actinomorphic +  and (3-)5-merous +
greenish yellow +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
tan +  and yellow +
angled +, subterete +  and fusiform +
sessile +  and short-petiolate +
N.C. +, Tenn. +  and Va. +
1600–1700 m +
tomentulose +
winged +  and beaked +
dispersed +
Spruce-hardwood forests, wooded slopes, open grassy summits +
indeterminate +
each +  and sessile +
0.2 cm2 mm <br />0.002 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
1.2 cm12 mm <br />0.012 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
cylindric;narrowly campanulate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
sessile +, short-petiolate +  and petiolate +
cauline +  and mid +
2-carpellate +
yellow +  and whitish +
persistent +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Flowering Aug–Sep. +
connate +  and distinct +
subequal +  and unequal +
exalbuminous +
Endemic +  and Conservation concern +
purple +  and green +
tomentulose +  and glabrous +
1 +  and 5 +
appendaged +  and truncate +
papillate +
Prenanthes cylindrica +
short;slender +
Prenanthes roanensis +
Prenanthes +
species +
5 cm50 mm <br />0.05 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +