392 Petrak, Die nordamerikanischen Arten der Gattung Cirsium. 
I 
30. Cirsium muticum. 
Radix sublignosa fusoidea. Caulis erectus, certc ad 2 m 
altus sulcato-striatus, imprimis apicem versus parce arachnoideus, j 
subdense vel remote foliosus a medio cir-J 
citer valde ramosus, ramis elongatis mono - ] 
vel tricephalis, remote foliosis vel subnu- 
d i s. Folia radicalia mihi ignota; caulina inferiora basi angustata, 
saepe quasi in petiolum attenuata sessilia supra glabrescentia vel 
parcissime arachnoideo-pilosa, subtus arachnoideo-tomentosa, 
canescentia, ambitu late oblonga vel oblongo-1 
clliptica alte subremote sinuato-pinnati- 
fida, laciniis irreg ulariter bi- vel trifidis, 
lobis anguste lineari-lanceolatis vel line- 
aribus, paullatim acuminatis, margine spinuloso- 
ciliatis, spinis infirmis stramineis 1 — 2 mm longis terminatis; 
caulina media et superiora gradatim minora, basi angustata semi- 
amplexicauli profunde spinoso-dentata sessilia, non decur- 
r e n t i a , ambitu lanceolato-oblonga, alte et remote sinuato- - 
pinnatifida, laciniis angustis lineari-lanceo- I 
latis, basin versus plus minusve curvatis, J 
irreg ulariter bi- vel tridentatis, dentibus tri- 
angulär i bus acuminatis, spinulis infirmis 1 — 3 mm longis termi- 
natis, margine spinuloso-ciliatis. 
Capitula in apice caulis et ramorum solitaria vel plus 
minusve aggregata, breviter pedunculata 
vel subsessilia, in axillis foliorum supre- 
morum saepe capitula 1 — 3 abortiva, brac- 
t e i s 1 — 2 lineari-lanceolatis vel linearibus ' 
remote spinuloso-dentatis, dentibus ad spi- 
nulas fere omnino reductis, capitulis multo 
brevioribus suffulta, ovata vel ovato-glo- 
b o s a , basi parum dilatata, vix excavata, saepe in 
pedunculum abruptiuscule contracta, 
2 1 / 2 — 37 2 cm longa, 2 — 3 cm lata. Involucri plus minusve 
appresse arachnoidei foliola exteriora et media 
e basi ovato-oblonga lanceolata, omnino 
appressa, apicem versus paullatim sed pa- 
rum attenuata, subobtusa nec spinulosa, 
dorso plus minusve viscido-carinata; interiora 
et intima gradatim longiora lineari-lanceolata, apice plus 
minusve purpurascentia, undulato-curvata, 
subscariosa acuminata, margine brevissime fimbriato-ciliata. Co- 
rollae purpureae raro albidae limbus ad medium circiter inaequaliter 
quinquefidus, laciniis angustissimis linearibus subobtusis, a tubo vix 
vel satisdistinctuseoque parum longior vel subaequilongus.Filamenta 
glabrescentia vel imprimis basin versus tantum parce longiuscule 
papilloso-pilosa. Pappus sordide albus flosculis parum brevior, setis 
plumosis apice saepe tantum scabridis, vix incrassatis. Achaenia ma- 
tura oblonga, compressa, vix nitida, fusca vel brunneo-canescentia, 
3V 2 — ■ f 1 /2 mm l° n g a »l 1 /a — 2mmlata. Bienne. Floret Julio-Augüsto. 
