P e t r a k , Die nordamerikanischen Arten der Gattung Cirsium. 50 1 
interdum fere 5-plo longior, raro subaequilongus, ad duas tertias 
vel ad basin fere, raro ad medium tantum regulariter, raro sub- 
regulariter quinquefidus. 
Subsect. Subcoriacea. Capitula mediocria vel majuscula, 
ovato-oblonga vel fere cylindrica, raro ovata subebracteata vel 
parum bracteata. 
Arizonica. Capitula ovata vel ovato-oblonga. Involucri plus 
minusve arachnoidei foliola exteriora dorso apicem versus saepe 
parum viscido-carinata. Corollae limbus vel ad duas tertias, vel 
ad basin fere aequaliter quinquefidus a tubo vix distinctus eoque 
parum longior. 
58. Cirsium arizonicum. 
Radix obliqua sublignosa. Caulis erectus, certe ad 1 m altus 
sulcato-striatus albo-tomentosus, remote vel subdense 
foliosus, apicem versus plus minusve ramo- 
sus, ramis subelongatis vel abbreviatis, 
subremote breviterque foliosis. Folia radicalia 
supra subdense vel parce arachnoidea canes- 
centia, subtus dense albo-tomentosa, in petio- 
lum anguste alatum remote sinuato-dentatum paullatim attenuata, 
ambitu lanceolata, ad medium circiter sub- 
remote s i n u a t o - p i n n a t i f i d a , laciniis late 
ovatis vel triangulari-ovatis, inaequaliter 
bi- vel tridentatis, dentibus triangularibus 
abruptiuscule acuminatis spinuloso-ciliatis 
spinis stramineis subvalidis 2 — 5 mm longis 
terminatis; caulina inferiora basi profunde spinoso-dentata 
semiauriculato-semiamplexicauli sessilia, non vel brevis- 
sime decurrentia, e basi late ovata vel raro 
parum angustata ambitu oblonga vel lan- 
ceolata, remote sinuato-dentata, dentibus late 
triangularibus vel ovato-triangularibus acuminatis, spinis strami- 
neis subvalidis 3 — 7 mm longis terminatis; caulina superiora 
gradatim minora, inferioribus simillima. 
Capitula in apice caulis et ramorum solitaria, ebrac- 
teata vel bracteis 1 — 2 multo brevioribus 
1 i n e a r i - 1 a n c e o 1 a t i s margine pectinato-spi- 
nulosis suffulta, basi vix dilatata, parum excavata, 
ovata v e 1 ovato-oblonga, cum flosculis 4 — 5 cm 
longa, 2 — 2 1 / 2 cm lata. Involucri plus minusve arach- 
noidei foliola exteriora et media e basi ovato-oblonga 
vel ovata a medio circiter abruptiuscule 
attenuata, dorso plus minusve viscido-cari- 
nata, erecto- vel subrecurvato-patentia, 
rigida, in spinas subvalidas 3 — 5 mm longas 
stramineas excurrentia, interiora et intima subito 
multo longiora, lineari-lanceolata elongato-acuminata, 
dorso plus minusve purpurascentia, recta, 
