Centaurea.] composite. 275 



**** " Pappus in many rows of different lengths, inner row longest, surrounded hy 

 a margin." — Bab. Man. 



XXV. Serkatula, Linn. Saw-wort. 



" Achenes obovate, compressed, glabrous. Pappus persistent, 

 pilose, hairs filiform in several rows, of which the interior is the 

 longest. Receptacle chaify, the scales split into linear bristles. 

 Involucre oblong, imbricated with straight unarmed scales. Fila- 

 ments papillose ; anthers with a short blunt appendage, ecaudate 

 at the base."^fir. Fl. 



1. S. tinctoria, L. Common Saw-wort. " Dioecious, leaves 

 entire or pinnatifid, involucral scales glabrous or slightly con- 

 nected with a cobweb-like down, outer ones ovate appressed, 

 inner linea coloured." — Br. Fl. p. 220. E. B. t. 38. 



/3. Flijvvers white, scales of the involucre not coloured. 



In woods, thickets and dry, heathy, bushy places ; common. Fl. July, August. 

 Fr. September, October. 2^. 



E.Med. — In Quarr copse, Shore copse, Stroud wood, Firestone copse, and 

 elsewhere about Byde, in plenty. Woods at Wootton and Cowes. 



W. Med. — Common in woods about Yarmouth, Newtown, Swainston, How- 

 ledge, &c. 



p. On a bank close to Whitwell. 



Achenia brown, linear-oblong, slightly curved, compressed and angular, with 

 several very slender ribs, glabrous. Pappus brownish white, sessile, rough with 

 sharp erect denticulalions, shorter than the florets, in several rows, the inner ot 

 which are longest. 



The flowers and general aspect of the Saw-wort remind one of some species of 

 Centaurea, for which it is sometimes mistaken by young botanists. 



***** " Pappus in many rows of different lengths : second row longest, placed 

 within the margin which surrounds the ejngynous dish, rarely 0." — Bab. 

 Man. 



XXVI. Centaueea, Linn. Knapweed. 



" Achenes compressed. Pappus pilose or scaly or none, rarely 

 exceeding the achene in length. Receptacle bristly. Involucre 

 imbricated. Florets of the disk perfect; of the circumference 

 narrow, funnel-shaped, irregular, without stamens or pistil (neu- 

 ter), longer those of the disk, and resembling a ray (sometimes 

 wanting)." — Br. Fl. 



f Scales of the involucre withhout spines. 



1. C. nigra, L. Black Knapweed. " Involucral appendages 

 ovate closely and deeply fringed with spreading capillary teeth, 

 lower leaves a,ngulato- dentate sublyrate, upper ones lanceolate, 

 pappus of short linear unequal scales. 



" a. Heads discoid. 



"/3. Heads rayed." — .Br. H. 225. C. nigrescens, Willd. Curt. Br. Entom. 

 V. t. 241. 



