This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Fig. 4122. Iva Imbricata Walt. Fl. Car. 232. 1788
Perennial by woody roots, glabrous or nearly so throughout, fleshy; stem 1°-2° high, simple, or sparingly branched. Leaves all but the lowest alternate, sessile, oblong-spatulate, or lanceolate, obtusish, mucronulate, entire, or rarely serrate, obscurely 3-nerved, the larger 1'-2' long, 3"-5" wide; heads about 4" broad, short-peduncled or nearly sessile, the upper often 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 staminate ones much more numerous; chaff of the receptacle spatulate.
On sandy sea-shores, southeastern Virginia to Florida and Louisiana. Bahamas; Cuba. July-Oct.
Iva annua Michx. Fl. Bor. Am. 2: 184. 1803. Not L.
Iva ciliata Willd. Sp. Pl. 3.: 2386. 1804.
Annual, hispid-pubescent; stem simple, or branched, 2°-6° high. Leaves nearly all opposite, ovate, petioled, scarcely fleshy, puberulent beneath, acuminate at the apex, abruptly or gradually narrowed at the base, coarsely and irregularly dentate, 3-nerved. the lower 4 -5' long; heads spicate-paniculate, about 1" broad; spikes dense or interrupted, erect, 2'-8' long; upper leaves linear-lanceolate, hispid, squarrose, much longer than the heads; bracts of the involucre 3-5, distinct or united below, hispid; fertile flowers 3-5, their corollas slender; staminate flowers 10-15.
In moist soil, Illinois to Nebraska, south to Louisiana and New Mexico. Plant with the aspect of an Ambrosia. Aug.-Oct.
Iva xanthiifolia Nutt. Gen. 2: 185. 1818.
Annual; stem much branched, pubescent or puberulent above, glabrous below, 3°-6° high. Leaves nearly all opposite, broadly ovate, long-petioled, acuminate at the apex, abruptly or gradually contracted at the base, coarsely and irregularly dentate, pale and canescent or puberulent beneath, roughish above, 3-ribbed, the lower often 6' long and wide; inflorescence spicate-paniculate, terminal and axillary, ample, naked; heads sessile or minutely peduncled, 1" broad or less; bracts of the involucre in 2 series of 5, the outer ovate, the inner obovate or truncate, concave, subtending the usually 5 achenes; corollas of the fertile flowers rudimentary or none; staminate flowers 10-15,their corollas obconic.
In moist soil, or sometimes in waste places, Ontario to Assiniboia, south to Wisconsin, Nebraska, New Mexico and Utah. In waste grounds farther east. Plant with the aspect of a Cheno-podium. July-Sept.