Vol. III.] 



RAGWEED FAMILY. 



293 



2. Iva axillaris Pursh. Small-flowered 

 Marsh Elder. (Fig. 3587.) 



Iva axillaris Pursh, Fl. Am. Sept. 743. 1814. 



Perennial by woody roots; stems herbaceous.ascend- 

 ing, glabrous or sparingly pubescent, simple or branch- 

 ed, i-2 high. Leaves sessile, entire or very nearly 

 so, obtuse, faintly 3-nerved, obovate, oblong, or linear- 

 oblong, Yz'-iy^' long, thick, somewhat fleshy, glabrous 

 or pubescent, the lower opposite, the upper alternate 

 and smaller, passing gradually into those of the 

 inflorescence; heads mostly solitary in the axils of the 

 leaves, 2 // -3 // broad, short-peduncled; involucre hem- 

 ispheric, about \W high; its bracts about 5, connate 

 at the base, or united nearly to the summit; pistillate 

 flowers 4 or 5, their corollas tubular. 



In saline or alkaline soil, Northwest Territory to west- 

 ern Nebraska, New Mexico, British Columbia and Cali- 

 fornia. May-Sept. 



3. Iva imbricata Walt. Sea-coast Marsh 



Elder. (Fig. 3588.) 

 Iva imbricata Walt. Fl. Car. 232. 1788. 



Perennial by woody roots, glabrous or nearly so 

 throughout, fleshy; stem i-2 high, simple, or 

 sparingly branched. Leaves all but the lowest al- 

 ternate, sessile, oblong-spatulate, or lanceolate, ob- 

 tusish, mucronulate, entire, or rarely serrate, ob- 

 scurely 3-nerved, the larger i / -2 / long, 3 // -5 // wide; 

 heads about 4" broad, short-peduncled or nearly 

 sessile, the upper ones longer than their subtending 

 leaves; involucre broadly campanulate, its bracts 

 6-9, not united, somewhat imbricated in 2 series; 

 fertile flowers 2-4, their corollas tubular, the stam- 

 inate ones much more numerous; chaff of the re- 

 ceptacle spatulate. 



On sandy sea-shores, Virginia (according to Gray hand 

 North Carolina to Florida and Louisiana. July-Oct. 



4. Iva 



ciliata Willd. 

 Elder. (Fig. 



Rough Marsh 

 3539.) 



Iva annua Michx. Fl. Bor. Am. 2: 184. 1803. Not L, ? 

 Iva ciliata Willd. Sp. PI. 3: 2386. 1804. 



Annual, hispid-pubescent; stem simple, or 

 branched, 2-6 high. Leaves nearly all opposite, 

 ovate, petioled, scarcely fleshy, puberulent be- 

 neath, acuminate at the apex, abruptly or gradu- 

 ally narrowed at the base, coarsely and irregularly 

 dentate, 3-nerved, the lower 4 / -5 / long; heads 

 spicate-paniculate, about i // broad; spikes dense 

 or interrupted, erect, 2'-$' long; upper leaves lin- 

 ear-lanceolate, hispid, squarrose, much longer 

 than the heads; bracts of the involucre 3-5, dis- 

 tinct or united below, hispid; fertile flowers 3-5, 

 their corollas slender; staminate flowers 10-15. 



In moist soil, Illinois to Nebraska, south to Louisi- 

 ana and New Mexico. Plant with the aspect of 

 Ambrosia. Aug. -Oct. 



