COMPOSITE. 17) 



pressed. Pappus double ; inner of long rough capillary bris- 

 tles ; outer very short, subulate. 



1. D. linariifolius Hook.: stem erect or somewhat decumbent; leaves 

 linear, rigid, spreading or recurved, rough on the margin ; scales of the 

 turbinate involucre rigid, 1-nerved ; the outer short and acute, inner usually 

 obtuse. D. linariifolius and rigidus Lind. in D. C. Chrysopsis linariifolia 

 Nutt. Aster linariifolius and rigidus Linn. 



Hills and rocky places. Can. to Car. Aug. Oct. 1J-. Stems 9 18 inches 

 high, often several from the same root, or branched from near the base. Leaves 

 about an inch long and one or two lines wide. Heads middle-sized, solitary and 

 terminal on the branches, forming an umbellate corymb ; rays pale violet ; disk 

 yellow. Narrow-leaved Diplopappus. 



2. D. umbellatus Torr. <$ G?: : stem striate, fastigiate-corymbose at the 

 summit; leaves elongated, lanceolate, attenuate-acuminate, tapering at 

 base usually into a short petiole, a little rough on the margin ; scales of the 

 short involucre obtusish, rather closely imbricate. D. amygdalinus and 

 umbellatus Hook. Diplostephium umbellatum D. C. Aster amygdalinus 

 Mich. A. umbellatus Ait. 



Low grounds. Can. to Car. Aug., Sept. 1|_. Stem 2 5 feet high, branched 

 at the summit. Leaves somewhat rough above, smooth beneath. Heads nume- 

 rous, in a level-topped corymb ; rays about 12, white or yellowish-white ; disk 

 yellowish. Umbetted Diplopappus. 



3. D. cornifolius Darlingt. : stem slender, somewhat pubescent, sparingly 

 and dichotomously corymbose-paniculate at the summit ; leaves elliptic, 

 acuminate, subcuneate at base, subsessile, entire, ciliate-hirsute on the 

 margin, hairy on the veins beneath ; scales of the involucre oblong-lan- 

 ceolate, rather obtuse, ciliate. Diplostephium cornifolium D. C. Aster 

 humilis Pursh. A. cornifolius WiUd. A. infirmus Mich. 



Woods. Can. to Car. Aug., Sept. 1}.. Stem 1 2 feet high, often flexuous, 

 smooth or sparingly pubescent. Heads usually few, on rather rigid peduncles; 

 rays white or yellowish ; disk yellowish. Cornus-leaved Diplopappus. 



4. D. paludosus Lind. : .stem slightly pubescent, somewhat corymbose at 

 the summit ; leaves linear, sessile or clasping, somewhat concave, subulate, 

 smooth, rough on the margin ; scales of the involucre somewhat squarrose. 

 Heleastrum paludosum D. C. Aster palludosus Ait. 



Borders of swamps. N. J. to Flor. Null. Aug. Nov. %.. Stem 12 feet 

 high, smooth nearly to the top. Heads 3 5, large and beautiful ; rays nume- 

 rous, bright blue. Torrey and Gray suggest that Aster paludosus of Nuttall is 

 a form of their A. elodes ; if so, this is probably not a northern species. 



Marsh Diplopappus. 

 15. ERIGERON. Linn. Fleabane. 



(From the Greek ept, early, and yepor, an old man; in allusion to the bald 

 heads of the receptacles after the flowers and fruit have fallen. Hook. Br. Fl.) 



Heads many-flowered ; the ray flowers numerous, very nar- 

 row, usually in more than one series, pistillate; those of the 

 disk tubular, perfect. Receptacle naked, flat, punctate or scro- 

 biculate. Involucre imbricate, with numerous linear scales. 

 Pappus mostly simple. 



