028 COMPOSITE. 



sciirc'ly denlk'uljitc near tlie apex, tlie otiicrs mucli smaller, the upper ones 

 iy or less long) i)assin<,' into ilie oblong-liut.ar obtuse bracts of the widely 

 spreading Hat j)ani<:le ; iiivoluerc ovoid, i.j - 20 flowered, tlie oblong scales 

 obtuse; rays few, notched; pappus coarse, shorter than the flowers; ovary 

 smooth. — I{ocky barrens of Tennessee (Dr. Galiiiifjer). 



S. rupestris, liaf. Smooth throughout; stem slender (2°-3° high); 

 leaves linear-lanceolate, entire, or tlie lowest ones slightly serrulate ; i)anicle 

 narrow, often simple; heads small with very short rays; achcnia pubescent. 

 — Kocky banks, Tennessee. 



LINDHEIMERIA, G/ay & Engclm. 



Kay -flowers 4-5. Scales of the involucre in two rows, the outer ones 

 linear, the inner ones oblong, adherent to the base of the fertile achenia, 

 and 10 tlie adjacent scales of the rece|)tacle. Achenium oval, flat, the nar- 

 row wind's jirolonged into a 2toothed pappus. Otherwise like Eerlandiera. 



L. Texana, Gray & Engelm. — Alabama (Mohr), and westward. — An- 

 nual, hirsute, erect, 1° - 2° high. Leaves oblong, dentate. Heads in a dichot- 

 oinous panicle, nodding. Flowers ytUow. 



IV A, L-. 



I. ciliata, Willd. Annual, hispid; stem brandling; leaves ovate, acu- 

 minate, coarsely serrate ; spikes dense, the bracts elongated ; scales of the 

 involucre 3-4, roundish, ciliate ; fertile flowers mostl}' 3. — Mississippi 

 (Carpenter), and westward. September. — Stem 2° -3° high. Leaves 3' -4' 

 long. 



AMBROSIA, Tourn. 



* * * Heads of sterile flowers densely ::piked, the lop-shaped involucre produced on 

 Oiie side into a long recurued appendcge. Fertile heads axillary, ^-anyltd. 



A. bidentata, Michx. Annual, liirsuto. very leafy ; leaves mostly alter- 

 nate, lanceolate, sessile or clasping, entire or with 2 short basal lobes ; fruit 

 acute, with 4 short spines. — Northern Missi.^sippi, and westward. — Stem 

 10-2° high. 



ACANTH03PEIIMUM, Schrank. 



Heads monoecious, radiate, many-flowered; the rays pistillate, in a single 

 row ; disk-flowers staminate, tubular, 5-toothed. Involucre of 5 elliptical 

 scales. Receptacle flat. Achenia compressed, armed on the back with rigid 

 hooked prickles, and enclosed in the outer scales of the chaffy receptacle. — 

 Diffusely branching herbs, with opposite leaves, and solitary heads of yellow 

 flowers. 



A. xanthioides, DC. Trostvate, pubescent ; leaves petioled, oval or 

 ohovate, toothed or entire ; chaff" of the receptacle which encloses the ache- 

 nium unarmed. — Introduced from South America several years ago, and 

 now widely disseminated. 



