Sacssurea. COiMPOSlT^. 453 



Serratula alpina, Linn. ; Engl. hot. t. 599. Circium montanum humile, 

 &c., Dill. Elth. t.lO.f. 81. 



(3. densa (Hook.! 1. c.) : stem somewhat decumbent; leaves nearly gla- 

 brous, dense, nearly all narrowly lanceolate ; corymb glomerate [inner scales 

 of the involucre very acute]. — S. alpina /?. subacaulis, Ledeb. ic. Alt. t. 73? 



y. viridis (DC. 1. c.) : leaves somewhat glabrous on both sides, elongated 

 lanceolate [or Unear], acuminate at both ends, denticulate, shorter than the 

 stem [inner scales of the involucre very acute]. — S. alpina, Hook. Sf Am. 

 hot. Beechey,p. 126. S. alpina y. remotifolia. Hook..' fl. Bor.-Am. 1. p. 

 303. S. monticola [printed S. multiflora in 1st ed.], Richards, appx. 

 Frankl. journ. ed. 2. p. 29. S. angustifolia, DC. I.e.? {Gmel. fl. Sibir. 

 2. p. 78. t. 33.?) 



Arctic America ; y. from Kotzebue's Sound ! and the coast between the 

 Mackenzie and Coppermine Rivers, nearly to the Saskatchawan, Richard- 

 son! (3. Higher Rocky Mountains, Drummond .' — The American seem 

 nearly to correspond with the two Siberian varieties as described by De 

 CandoUe. The salient teeth of the leaves in Hooker's var. (3. are some- 

 times retrorse. 



Subtribe 2. Centaurieje, DC. — Heads discoid, many-flowered; the 

 marginal flowers usually neutral, with the corolla irregular, and much larger 

 than the disk-flowers. Scales of the involucre imbricated, variously ap- 

 pendiculate. Achenia with a more or less lateral basilar areola. Pappus 

 pilose, setose, or chaffy, never plumose, sometimes wanting. 



169. CENTAUREA. Linn. (excl. spec.) ; Less. ; DC. prodr. 6. p. 565. 



Heads many-flowered ; the ray-flowers mostly large and sterile, sometimes 

 wanting. Involucre imbricated, various. Receptacle setose. Achenia com- 

 pressed. Pappus occasionally wanting or nearly so, but usually composed 

 of scabrous filiform bristles, in one or more series, the inner often smaller 

 and somewhat connivent. — Herbs of varied aspect (chiefly natives of the 

 Mediterranean region and of Middle Asia) ; with alternate leaves, and 

 solitary heads. 



§ 1. Involucre nearly globose or depressed ; the exterior scales with a coriaceo- 

 scarious pectinate-fringed appendage ; the inner longer and scarious : rays 

 much longer than the disk : pappus of rigid nearly homogeneous scabrous 

 bristles, somewhat in a single series, caducous : achenia with a nearly ter- 

 minal areola (natives of America !). — Plectocephalus, Don. 



1. C. Americana (Nutt.) : stem erect, striate-grooved, sparingly branched, 

 thickened under the heads; leaves sessile, glabrous, often scabrous; the lower 

 oblong-ovate, repand-toothed; the upper lanceolate, acute; head (very large) 

 not bracteate ; scales of the involucre all with pectinate appendages ; rays 

 elongated ; the segments very long and slender. — Nutt. ! in jour. acad. 

 Philad. 2. p. 117 ; Bart. fl. Amer.-Sept. t. 50 ; Colla, hort. Ripul. 1. p. 

 119, t. 6 ; DC! prodr. 6. p. 575. C. Nuttallii, Spreng. syst. 4 {suppl.) p. 

 298. C. Mexicana, DC. I. c.1 Plectocephalus Americanus, Don, in Brit, 

 fl. gard. ser. 2. t. 51. 



Western Arkansas, Louisiana, &c. Nuttall ! Dr. James! Dr. Pitcher ! 

 Dr. Leavenworth! Texas, Drummond! Common in cultivation. — (T) 

 Plant 2-3 feet high, with very large showy heads. Flowers pale purple. 



