COMPOSITE FAMILY. 221 



or neutral, always without stamens ; or with strap-shaped 

 corollas entirely wanting. Plants destitute of milky or colored 

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



A. No strap-shaped corollas or true rays; i.e. the head discoid. (B, p. 224.) 



* Branches of the style filiform-subulate and rough all over with minute bristles ; 



receptacle not chaffy ; flowers not yellow (* * and * * * this page). 



1. VERNONIA. Heads corymbed, 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 fine scales or scale-like bristles. Leaves alternate. 



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



usually very minutely puberulent under a lens, the stigmatic surface below the 

 middle ; receptacle not chaffy ; flowers not yellow. 



+- Pappus ; leaves opposite. 



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



cated scales. Akene 4-5-angled. 



+- -- 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 chaffy scales, mostly tapering into a slender stiff rough bristle. 

 Leaves opposite. 



- -t- -t- Pappus of slender bristles ; leaves various. 

 M- Stem twining ; involucral scales 4. 



5. MIKANIA. Heads of 4 flesh-colored flowers. Corolla 5-toothed. Akenes 5-angled ; 



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



-w- -H- Stem erect ; involucral scales more than 4. 



6. EUPATORIUM. 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. KUHNIA. 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 several or many rose-purple flowers, surrounded by a more or 



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

 10-ribbed ; pappus 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 even with 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 Thistle-like, the heads with very many flowers, all alike and mostly 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 bristly points. 



H- Pappus of many long plumed bristles ; receptacle with bristles between the flowers. 



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

 pointed. Akenes flattish, not ribbed. Filaments of the stamens separate. 



