218 Mr. D. Don’s Descriptions of new Genera and Species 
cumference are clearly nothing more than the scales composing 
the inner series of the involucrum. The plumose pappus com- 
pared with that of the inner floret of the partial capitula of 
Polyachyrus, a genus hereafter to be described, the form and 
structure of their corolla, the outer lamina of which is tra- 
versed in both by four distant slender nerves, and the habit of 
the plants themselves, show that there is a considerable degree 
of affinity between these two genera. 
PrirvRvs. 
Flosculi equales. Pappi radiis plumosis, duplici serie dispositis. 
~ Involucrum subsequale. 
Involucrum duplici ordine poly-(18—20)phyllum, subzequale : 
foliolis ovato-lanceolatis, trinerviis, apice membranaceo 
 acuminato radiatis. Receptaculum nudum. Flosculi omnes 
hermaphroditi, tubulosi, bilabiati, equales; labio exteriore 
 ligulato, 4-nervio, obtuse tridenticulato ; interiore bipartito, 
demüm revoluto: segmentis linearibus, obtusis, binerviis. 
Anthere coalitæ, basi longè bisetosz: setis simplicibus : 
appendiculá lineari-lanceolatá, acuta. Stigma bipartitum : 
laciniis semicylindricis, recurvis, apice dilatato-truncatis, 
 pruinosis. Achenia elliptico-oblonga, compressa, densé pa- 
| pilloso-g andulosa, apice angustata, disco parvo. Pappi 
radiis crassiusculis, eleganter plur osis, mollissimis, Eici 
ordine digestis, basi dilatata imbricatis! deciduis. - 
Herba perennis, humilis, cespitosa, facie Dauci v. Efüünante, 
. setulis erectis, glanduliferis, copiosissimé instructa. Radix 
fusiformis, ramosa. Caulis erectus, teres, subramosus, tri- 
- uncialis, vix calami scriptori crassitie. Folia supradecom- 
posita, dense ‘glandulosa, pollicaria v. sesquipollicaria : seg- 
mentis linearibus, obtusis, sesquilineam longis. Petioli foliis 
longiores, maxim dilatato-membranacei ; inferiorum foliorum 
latiores 
