486 P e t r a k , Die nordamerikanischen Arten der Gattung Cirsium. 
56. Cirsium Howellii. 
Caulis erectus, ut videtur ad 1 m altus, sulcato-striatus, 
crassus, albo-tomentosus, subremote foliosus, apice 
tantum breviter ramosus, ramis plus mi- 
nusve abbreviatis subnudis, mono- vel tri- 
c e p h a 1 i s. Folia radicalia et caulina inferiora mihi ignota; 
caulina media basi late semiamplexicauli profunde spinoso-dentata 
sessilia, non vel brevissime decurrentia, utrin- 
que dense arachnoideo-tomentosa, albida, 
ambitu lanceolata vel 1 a n c e o 1 a t o - o b 1 o n g a; 
ad medium circiter remote sinuato-pinna- 
tifida, laciniis inaequaliter bi- vel trifidis, 
lobis t r i a n g u 1 a r i b u s vel triangulari-line- 
aribus acuminatis vel subobtusis, margine 
plus minusve revolutis, spinuloso-ciliatis, s p i n i s 
subvalidis stramineis ad 5 mm longis termi- 
natis; caulina superiora et suprema gradatim minora, ambitu 
lineari-lanceolata, magis remote sinuato-pinnatifida spinis parum 
longioribus validioribusque armata, ceterum ut folia caulina 
media. 
Capitula in apice caulis et ramorum plerumque 2 — 3 
plus minusve aggregata, subsessilia vel bre- 
viter pedunculata raro solitaria, bracteis 
1 — 3 linearibus, valde remote sinuato-den- 
tatis plus minusve longioribus, subaequi- 
longis vel brevioribus suffulta, ovata vel 
ovato-globosa, basi plus minusve dilatata et excavata, 
cum flosculis 2 x / 2 — 3 cm longa, 2 cm lata. Involucri p ä r c e 
arachnoidei foliola exteriora et media e basi late 
ovata lanceolata, dorso viscido-carinata, 
a b r u p t i u s c u 1 e acuminata, spinulis flaves- 
centibus 1 — 2 mm longis subvalidis termi- 
nata; interiora et intima longiora, lineari-lanceolata paullatim 
attenuata et acuminata, apice plus minusve undulato-curvata, 
subscariosa. Corollae probabiliter ochroleucae vel albidae 
limbus vix ad medium inaequaliter quinquefidus, a tubo non vel 
vix distinctus eoque subduplo fere longior. Filamenta omnino 
dense longiuscule crispule papilloso-pilosa. Pappus sordide albus, 
setis plumosis, apice saepe tantum scabridis, parum vel non 
clavellatis. Achaenia matura oblonga vel ovato-oblonga, com- 
pressa, brunnea, 6 — 6 x / 2 mm longa, 2 x / 2 — 3 mm lata, nitida. Bienne ? 
Floret Julio — August o. 
Synonyma: 
? Carduus undulatus var. Douglasn Greene in Proc. Acad. 
Nat. Sei. Philad. 1892, p. 360 (1893) excl. syn. Cirsium Douglasii 
DC. Prodr. VI, p. 643 (1837). 
Cirsium Brewer ssp. Howellii Petrak in schedis 1914. 
Distributio: Species, ut videtur, endemica, adhuc 
tantum in saxosis lapidosis apricis loco infra indicato in civitate 
