COMPOSITAE. 



i. Tanacetum vulgare L. 

 Fig. 4569. 



VOL. III. 



Tansy. 



Tanacetum vulgare L. Sp. PI. 844. 1753. 

 Tanacetum vulgare crispum DC. Prodr. 6: 128. 



1837- 



Stem stout, usually simple up to the inflo- 

 rescence, glabrous, or sparingly pubescent, 

 ii-3 high. Leaves pinnately divided into 

 linear-oblong, pinnatifid or incised, often crisp- 

 ed segments, the lobes acute, usually serrate; 

 lower segments of the leaves often smaller 

 than the others; basal leaves often i long; 

 heads commonly numerous, 3" -5" broad, 

 rather shqrt-peduncled ; involucre depressed- 

 hemispheric, its bracts oblong-lanceolate, ob- 

 tuse, or the outer acute, slightly pubescent or 

 ciliate ; receptacle flat ; flowers yellow ; mar- 

 ginal corollas with short oblique 3-toothed 

 limbs ; pappus a short crown. 



Along roadsides, mostly escaped from gardens, 

 Nova Scotia and Ontario to Minnesota, Oregon, 

 Nevada, North Carolina and Missouri. Natural- 

 ized or adventive from Europe. Bitter-buttons. 

 Hindheal. Ginger-plant. July-Sept. 



2. Tanacetum huronense Nutt. Lake 

 Huron Tansy. Fig. 4570. 



Tanacetum huronense Nutt. Gen. 2: 141. 1818. 



Villous-pubescent throughout, at least when 

 young, less so when mature, i-2 high. Leaves 

 2-pinnately divided, the lobes dentate or incised, 

 acute, the lower segments commonly smaller than 

 the others ; heads 1-8, 6"-8" broad, on very stout 

 pubescent peduncles ; involucre depressed-hemi- 

 spheric ; marginal flowers with 3-5-lobed limbs, 

 often expanded into short rays; pappus a short 

 crown. 



In moist soil, especially along streams or lakes, 

 New Brunswick to Hudson Bay, Maine, Lake Su- 

 perior, Alaska and Oregon. July-Sept. 



94. ARTEMISIA [Tourn.] L. Sp. PI. 



845- 1753- 



Odorous herbs or shrubs, often canescent or 

 tomentose, with alternate leaves, and small pendu- 

 lous or erect, discoid racemose spicate glomerate or paniculate heads of greenish or yellowish 

 flowers. Involucre ovoid, oblong, or broadly hemispheric, its bracts imbricated in few 

 series, the outer gradually shorter. Receptacle flat, convex or hemispheric, naked or pubes- 

 cent, not chaffy. Central flowers perfect, sometimes sterile, with abortive ovaries and undi- 

 vided style, sometimes perfect and fertile, with truncate style-branches ; marginal flowers 

 usually pistillate and fertile, their corollas 2-3-toothed, or flowers all perfect and fertile in 

 some species. Anthers obtuse and entire at the base, often tipped with subulate appendages. 

 Achenes obovoid or oblong, 2-ribbed or striate, rounded at the summit, usually bearing a 

 large epigynous disk. Pappus none. [Named for Artemisia, wife of Mausolus.] 



About 225 species, natives of the northern hemisphere and southern South America. Besides 

 the following, some 40 others occur in the western parts of North America. Type species : Arte- 

 misia vulgaris L. 



* Marginal flowers pistillate; central flowers perfect, sterile. 



a. Biennial or perennial herbs. 

 Leaves pinnately dissected into narrowly linear lobes. 



Heads very numerous, i" broad ; leaves mostly glabrous. i. A. caudata. 



Heads 2" broad, in narrow panicles ; leaves silky-pubescent. 



Heads few ; involucre brown, mostly pubescent. 2. A. borealis. 



Heads numerous; involucre green, mostly glabrous. 3. A. canadensis. 



Leaves linear, the lower sometimes 3-cleft or pinnately divided. 



Leaves glabrous. 4. A. dracunculoides. 



Leaves finely and densely pubescent. 5. A. glauca. 



b. Shrubby, silvery-canescent ; heads small and numerous. 6. A. filifolia. 



