Petrak, Die nordamerikanischen Arten der Gattung Cirsium. 271 
ad duas tertias circiter subregulariter quinquefidus 
eoque duplo vel fere triplo longior. 
3. Megacephala. 
Capitula mediocria vel magna, subebrac- 
teata, ovato-oblonga vel ovata. Involucri parce 
arachnoidei vel fere glabrescentis foliola exteriora et media e basi 
ovato-oblonga lanceolata, ad duas tertias fere hori- 
zontaliter vel erecto-patentia, margine an- 
gustissime stramineo-marginata ibique b r e - 
viter spinuloso-ciliata, paullatim acuminata, ri- 
gida, spinis subvalidis sed brevibus terminata, interiora et intima 
multo longioria linearia, recta, elongato-acuminata, plus minusve 
purpurascentia. Corollae limbus vix ad medium 
aequaliter quinquefidus, a tubo non vel vix 
distinctus eoque subduplo vel fere triplo 
longior. 
ö 
1. Cirsium Andersonii. Caulis elatus ramosus, ramis plus 
minusve elongatis subnudis plerumque monocephalis. Folia non 
decurrentia. 
2. Subsect. Conspicua. 
Capitula magna vel maxima, ebracteata 
velsubebracteata, o v.a to-oblonga vel ovata, 
raro ovato-globosa vel globosa. Involucri parce 
arachnoidei foliola exteriora et media e basi late ovato-oblonga 
lanceolata, paullatim vel abruptiuscule acuminata, a medio 
circiter vel ad duas tertias fere erect.o- vel 
plus minusve r e c u r v o - p a t e n t i a , margine 
vulgo pectinato-spinosa, spinis subvalidis termi- 
nata, interiora et intima multo longiora, linearia vel lineari-lan- 
ceolata, apicem versus plus minusve scarioso- 
marginata ibique saepe eroso-fimbriata 
plus minusve purpurascentia vel f lavescen- 
tia, flosculis plus minusve longioribus vel 
subaequilongis. 
A. Corollae limbus ad basin fere aequaliter 
quinquefidus. Involucri foliola interiora et intima plus 
minusve flavescentia. 
1. Cirsium subcoriaceum. Caulis elatus ramosus, ramis sub- 
elongatis monocephalis vel quasi racemoso-polycephalis. Folia 
caulina inferiora sinuato-pinnatifida, laciniis oblongo-lanceolatis 
vel lanceolatis, inaequaliter dentatis. 
B. Corollae limbus ad duas tertias vel ad me- 
dium tantum aequaliter quinquefidus. In- 
volucri foliola interiora et intima plus minusve purpuras- 
centia. 
a) Involucri foliola exteriora margine dense pectinato- 
spinulosa, spinulis ad 3 mm longis. 
