P e t r a k , Die nordamerikanischen Arten der Gattung Cirsium. 
457 
spinnwebig wolligen Hüllschuppen entweder sehr klein und 
schwächlich oder ziemlich lang, nadelartig, aufrecht abstehend 
und kräftiger. 
48. Cirsium hydrophilum. 
* Caulis erectus, certe ad 2 m altus, parce arachnoideus vel 
fere glabrescens sulcato-striatus, remote foliosus, a 
medio circiter vel apice tantum ramosus, 
rainis nunc abbreviatis, nunc plus minusve 
elongatis remote foliosis 1 — 3-cephalis. Folia 
radicalia supra parce breviterque crispule p i - 
losa, ceterum glabrescentia vel parcissime 
arachnoidea, -subtus plus minusve, vulgo 
parce arachnoideo-tomentosa, in petiolum elon- 
gatum angustissime alatum, remote spinuloso-ciliatum vel fere 
integerrimuin paullatim attenuata, ambitu elongato- 
oblonga vel lanceolato-oblonga, ad medium 
circiter remote s i n u a t o - p i n n a t i f i d a , laci- 
niis ambitu late ovatis vel triangulari- 
ovatis, ad unam tertiam circiter inaequa- 
liter bi- vel tridentatis, dentibus triangu- 
lär ibus vel lanceolato-triangularibus, ab- 
rupt i u s c u 1 e acuminatis vel subobtusis, mar- 
gine spinuloso-ciliatis, spinulis infirm i s 1 — 3 mm 
longis stramineis terminatis; folia caulina in- 
feriora et media supra glabrescentia, subtus arachnoideo-canes- 
centia vel fere glabrescentia, basi angustata semiamplexicauli 
sessilia, breviter — x / 2 — 3 cm — decurrentia, alis 
latis, remote spinuloso-dentatis, dentibus 
saepe fere omnino ad spinas reductis, ambitu 
anguste lanceolata, ad medium circiter remote sinuato-pinnatifida, 
laciniis ambitu late ovatis vel triangulari-ovatis, ad medium 
circiter inaequaliter bi- vel tridentatis, dentibus triangularibus 
acuminatis, spinis stramineis subvalidis 3 — 7 mm longis terminatis; 
caulina superiora gradätim minora, inferioribus simillima, suprema 
bracteiformia, e basi late ovato-oblonga profunde spinoso-dentata 
ambitu anguste lanceolata, breviter decurrentia, remote sinuato- 
dentata, dentibus fere omnino ad spinas reductis. 
Capitula in apice caulis et ramorurri solitär i a vel 
saepe 2 — 3 s u b a g g r e g a t a , racemose dispo- 
sita, breviter pedu neu lata vel raro fere 
subsessilia, bracteis 1 — 3 multo brevioribus 
lineari-lanceolatis, imprimis basin versus 
spinoso-dentatis, dentibus omnino fere ad 
spinas reductis suffulta, globosa vel ovato- 
globosa, cum flosc.ulis 2 l j 2 — 3 cm longa, l l / 2 — 2 cm lata, 
basi parum dilatata et excavata. Involucri glabrescentis 
vel basi tantum parcissime arachnoidei foliola 
exteriora et media e basi ovato-oblonga paullatim 
acuminata, dorso plus minusve, plerumque 
