Genus i. 



RAGWEED FAMILY. 



339 



i. Iva frutescens L. Marsh Elder. High- 

 water Shrub. Fig. 4120. 



Iva frutescens L. Sp. PI. 989. 1753. 



Iva oraria Bartlett, Rhodora 8 : 26. 1906. 



Perennial, shrubby or herbaceous, somewhat 

 fleshy ; stem paniculately branched above, mi- 

 nutely pubescent, or sometimes glabrous below, 

 3-i2 high. Leaves oval, oblong, or oblong- 

 lanceolate, all the lower ones opposite, short- 

 petioled, 3-nerved, acute or obtusish, serrate, nar- 

 rowed at the base, the lower 4'-6' long, i'-z' wide, 

 the upper smaller and narrower, passing gradu- 

 ally into those of the racemose inflorescence 

 which are much longer than the short-pedicelled 

 heads; involucre depressed-hemispheric, its bracts 

 about S, orbicular-obovate, separate ; fertile flow- 

 ers about 5, their corollas tubular. 



Along salt marshes and on muddy sea-shores, 

 Massachusetts to Florida and Texas, the northern 

 plant (7. oraria) mainly broader-leaved and less 

 shrubby than the southern. Jesuits'- or false Jesuits'- 

 bark. July-Sept. 



2. Iva axillaris Pursh. Small-flowered Marsh 

 Elder. Fig. 4121. 



Iva axillaris Pursh, Fl. Am. Sept. 743. 1S14. 



Perennial by woody roots; stems herbaceous, ascend- 

 ing, glabrous or sparingly pubescent, simple or branched, 

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

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

 oblong, i'-ij' long, thick, somewhat fleshy, glabrous 

 or pubescent, the lower opposite, the upper alternate 

 and smaller, passing gradually into those of the in- 

 florescence; heads mostly solitary in the axils of the 

 leaves, 2"-?," broad, short-peduncled ; involucre hemi- 

 spheric, about ii" 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. Manitoba and North Dakota to 

 western Nebraska. New Mexico, British Columbia and Cali- 

 fornia. May-Sept. 



3. Iva imbricata Walt. Sea-coast Marsh 

 Elder. Fig. 4122. 



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 

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

 tusish, mucronulate, entire, or rarely serrate, obscurely 

 3-nerved, the larger 1-2' long, 3"-S" 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. 



