IvA. COMPOSlTiE. 287 



§ 1. Involucre several-flowered, coivposed of 3-5 distinct and nearly 1-seriate, 

 or partly united scales. 



1. /. ciliata (Willd.) : annual, hirsute or hispid, branched; leaves oppo- 

 site, on slender hispid or ciliate petioles, ovate, acuminate, coarsely and ir- 

 regularly serrate-toothed, scabrous above, softly pubescent or slightly canes- 

 cent beneath; the upper ones ovate-lanceolate; spikes dense, elongated, 

 paniculate; the conspicuous lanceolate or ovate-lanceolate bracts, and the 

 (3-4, distinct) roundish unequal scales of the involucre, hispidly ciliate ; fer- 

 tile flowers mostly 3; chaff of the receptacle linear-filiform. — Willd. spec. 3. 

 p. 2386 ; Piirsk, fl. 2. p. 580 ; DC. I. c. I. annua, Mickv. ! fl. 2. p. 184, 

 not of Linn. Ambrosia (vel Iva) Pitcheri, Ton. ! mss. {in herb. Hook.) ; 

 Hook, compan. to hot. mag. 1. p. 99. 



/?. bracts linear and much elongated, ciliate only near the base. — Ambro- 

 sia Pitcheri /3., Hook. I. c. 



Swamps and moist places, Illinois ! and Missouri ! to Louisiana ! Arkan- 

 sas ! and Texas ! common. Aug.-Oct. — Plant 2-6 feet high, coarse and 

 weed-like in appearance, with much the habit of an Ambrosia. Leaves 3-4 

 inches long. Spikes 3-6 inches long, numerous; the bracts longer (in ,5. 

 many times longer) than the deflexed almost sessile heads. Scales of the 

 involucre 3, rarely 4 or 5, very obtuse, unec|ual. Fertile flowers sometimes 

 4 or 5, inconspicuous when young ; the corolla slender, truncate. Achenia 

 obovate, lenticular. Sterile flowers 10-15, greenish ; the style penicillate at 

 the apex. 



2. I. frutescens (Linn.) : shrubby, nearly glabrous, much branched ; leaves 

 opposite or the upper ones alternate, a little fleshy, oval or lanceolate, some- 

 what scabrous, coarsely and sharply serrate ; the uppermost, or bracts, line- 

 ar-lanceolate, entire ; heads depressed-globose, somewhat pedicellate, solitary 

 or in pairs in the axils of the bracteal leaves, forming foliaceous paniculate 

 racemes ; scales of the involucre 5, orbicular, glabrous, distinct; fertile flow- 

 ers 5; chaflTof the receptacle linear-filiform. — Linn.! ammi. acad. 3. p. 25, 

 ^- sjjec. 2. p. 989 ; Wcdt. ! Car. p. 232 ; Lam. ill. t. 166. /. 2 ; Michx. ! fl. 

 2. p. 184 ,• Willd. I. c. ; Pursh! fl. 2. p. 580 ; Ell. sk. 2. p. 475 ; Bigel. fl. 

 Bost. ed. 2. p. 317; DC! I. c. 



Sea-coast, and muddy shores of large rivers near the ocean, Massachu- 

 setts ! to Florida ! and Louisiana ; common. July-Sept. — Shrub 3-8 feet 

 high ; the stems annually dying down to near the ground in the Northern 

 States. Leaves of a greyish hue, sometimes ternate. Heads recurved, 

 greenish. Corolla of the fertile flowers very small, 2-3-toothed. Achenia 

 when young sprinkled with resinous dots as in most other species. — Marsh 

 Elder. 



3. /. axillaris (Pursh) : much branched from the somewhat ligneous base, 

 low, covered with minute appressed hairs or nearly glabrous ; leaves alter- 

 nate or the lower opposite, fleshy, lanceolate-linear, oblanceolate, or spatu- 

 late-oblong, entire, obscurely 1-3-nerved, narrowed at the base, sessile ; 

 heads solitary in the axils of the leaves, on short recurved pedicels; scales 

 of the campanulate involucre 4-5, distinct, or united to the middle ; fertile 

 flowers 4-5; chafT of the receptacle filiform-linear. — Pursh! fl. {suppl.) 2. 

 p. 743 ; Nutt. ! gen. 2. p. 185 ; Hook. ! fl. Bor.-Am. 1. p. 309, t. 106. L 

 axillaris & L foliolosa, Nutt.! in trans. Amer. phil. soc. {n. ser.) 7. ]). 346. 

 Dry sandy and saline soil. Upper Missouri, Bradbury! Nuttall! Mr. 

 Nicollet ! Saskatcliawan, Drtmimond ! &c. and on the Oregon from the 

 Rocky Mountains to the Grand Rapids, Douglas ! May-July. — Root an- 

 nual according to Pursh and Hooker, 'perennial & herbaceous,' Nuttall, 

 certainly perennial or even ligneous in the fine specimens collected by Mr. 

 Nicollet. Stems ascending, a span to a foot high ; the plant with much the 



