Prenanthes racemosa
Prenanthes carrii
glaucous rattlesnakeroot, glaucous white lettuce, prenanthe à grappe, purple rattlesnake-root
Carr's rattlesnakeroot
erect, green or light purple, simple, (stout), glabrous and glaucous proximally, setose or hispid distally.
erect, simple, glabrous or strigose proximally, tomentose distally.
proximal usually present at flowering;
petioles broadly winged, (1–15 cm);
blades broadly oblanceolate to spatulate, 4–25 × 1–8 cm, coriaceous, bases attenuate, clasping, margins entire or weakly denticulate, apices obtuse or rounded, faces glabrous;
mid cauline sessile, clasping;
distal sessile and reduced.
proximal usually present at flowering; petiolate (petioles 2.2–3 cm);
blades (light green) sagittate to ovate, 13–25 × 7–12 cm, thin, bases attenuate, margins coarsely and irregularly dentate, apices acute to rounded, faces glabrous or lightly setose along veins;
distal reduced to bracts.
campanulate, 11–12 × 4–7 mm.
cylindric to campanulate, 4–9 × 2–3 mm.
9–29;
corollas usually pinkish, sometimes white or lavender, 7–13 mm.
9–11;
corollas white to creamy, 11.5–13.5 mm.
7–14, green to purple, lanceolate to linear, 10–12 mm, margins scarious, sparsely to densely setose.
8, green to rose, linear-subulate to lanceolate, 9–11 mm, (apices minutely ciliate) faces glabrate (midribs sparingly hispid).
of 8, dark green to purple, narrowly triangular-subulate bractlets 2–4 mm, coarsely setose.
of 5–12, linear-subulate to narrowly lanceolate bractlets 2–4 mm, hispid.
(ascending) in (elongate) narrowly racemiform or paniculiform arrays.
in paniculiform arrays.
golden brown, sub-cylindric, subterete, 5–6 mm, indistinctly 8–12-ribbed;
pappi pale yellow, 6–7 mm.
golden yellow to tan, subcylindric, angled to terete, 6–7 mm, prominently 12–15-ribbed;
pappi white to tan or yellow, 7–8 mm.
= 16.
Prenanthes racemosa
Prenanthes carrii
Prenanthes racemosa is recognized by its erect, stout, simple habit, glaucous stems, spatulate proximal leaves with broadly winged petioles and rounded to obtuse apices, heads borne in narrow racemiform arrays, purple and hairy phyllaries, and usually pinkish corollas. It is most similar to P. aspera, which differs in its generally smaller stature, more hirsute stems, leaves that are hispid abaxially, proximal leaves usually withered by flowering, and creamy white or yellow corollas. Hybrids between P. racemosa and P. trifoliolata, known as P. ×mainensis, occur in the northeastern United States and southeastern Canada (see discussion under P. trifoliolata).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Prenanthes carrii is recognized primarily by its relatively tall size and long-petiolate, sagittate proximal and mid-cauline leaves, which are similar to those of P. alata and P. sagittata, species found far to the north. It is known only from the southwestern Edwards Plateau. It is thought to be closely related to P. barbata (J. R. Singhurst et al. 2004).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
Flora NW
IL Wildflowers
MI Flora
MN Wildflowers
MO Plants
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
