COMPOSITE FAMIIA'. 221 



or neutral, always witliout stamens ; or with strap-shaped 

 corollas entirely wanting. Plants destitute of milky or colored 

 juice. (Series II., p. 228.) 



A. Ko strap-shaped corollas or true rays ; i.e. the head discoid. (B, p. 224.) 



* Branches of the stijle fiUform-sithulatc and rough all over with mimite bristles; 



receptacle not chaffi/ ; jlowers not yellow (* » and * * * this page). 



1. VEltNONIA. Heads coryuibed, with an involucre of many imbricated scales, and 15 to 



30 or more rose-purple flowers. Lobes of the corolla slender. Akenes cylindrical, 

 several-ribbed ; pappus of copious hair-like bristles, surrounded at base by an outer 

 set of very short and iine scales or scale-like bristles. Leaves alternate. 



* * Branches of the style long and slender or mostly rather club-shaped, obtuse, 



usually very minutely puher a lent under a lens, the stigmatic surface below the 

 middle ; receptacle not chaffy ; flowers not yelloio. 

 ■t- Pappus ; leaves opposite. 



2. PIQUEELV. Heads very small, of 3-5 whitish flowers, and involucre of 4 or 5 imbri- 



cated scales. Akene 4-.5-anffled. 



-i- -i- Pappus stiff, mostly scale-like ; leaves whorled or opposite. 



3. SCLEROLEPIS. Heads many-flowered, flesh-colored, the scales of the involucre 



equal. Corolla 5-toothed. Akenes 5-angled. Pappus a single row of 5 hard, oval, 

 obtuse scales. Leaves whorled. 



4. AGERATUM. Heads small and few-flowered, blue (in ours ; in others rose-colored), 



with a cup-shaped involucre of imbricated narrow bracts ; receptacle flattish ; the 

 pappus of a few chafl'y scales, mostly tapering into a slender stitf rough bristle. 

 Leaves opposite. 



■i- -i- -I- Pappus of slender bristles ; leaves various. 



++ Stem twining ; involucral scales 4. 



5. MIKANLV. Heads of 4 flesh-colored flowers. Corolla 5-toothed. Akenes 5-angIed ; 



pappus a ro\y of hair-like, naked (barely roughish) bristles. Leaves opposite. 

 ■M- ++ Stem erect ; involucral scales more than 4. 



6. EUPATORIITM. Heads of 3 or more flowers, and an involucre of several or many scales. 



Corolla 5-toothed. Receptacle flat or merely convex. Akenes 5-angled ; pappus a row 

 of hair-like naked (rarely rough) bristles. Leaves alternate, opposite, or whorled. 



7. KUHNL\. Heads small, of 10-25 dull cream-colored flowers, surrounded by a few lanceo- 



late scales of the involucre. Corolla slender, barely 5-toothed. Akenes cylindrical, 

 many -striate ; pappus a row of white plumose bristles. Leaves mostly alternate. 



8. LIATRIS. Heads of sever.il or many rose-purple flowers, surrounded by a more or 



less imbricated involucre. Lobes of the corolla rather long. Akenes slender, about 

 10-ribbed ; pajipus of many long and slender bristles, which are plumose or else 

 beset with a short beard or roughness for their whole length. Heads spicate or 

 racemose. Leaves alternate, entire, often resinous-dotted. 

 • » « Branches of the style mostly short, often united, with obtuse or truncate tips, 

 naked or sometimes hairy appendaged (or eventcith a minute hairy tip), the 

 stigmatic surface either extending to the tip or to an appendage ; receptacle 

 either naked or chaffy ; flowers of many colors. 



+- Thistles or Tlii.^tle-like, the heads with very many flowers, all alike and mo.itly perfect. 

 Branches of the style short or united, even to the tip. Scales of the involucre 

 many-ranked, these or the leaves commonly tipped with prickly or bri.^tly points. 



+*• Pappus of many long plumed bristles ; receptacle with bristles betwem the flowers. 



(65) CXICr.S. Scales of the involucre not fleshy-thickened, prickly-tipped or else merely 

 pointed. Akenes flatti.sli, not ribbed. Filaments of the stamen.-; sej.arate. 



