COMPOSITE. (COMPOSITE FAMILY.) 181 



cultivated grounds across the continent, known variously as " Roman Worm- 

 wood," "Ragweed," and " Bitter- weed." 



3. A. psilostachya, DC. From slender running rootstocks, stouter, 2 

 to (jfeet high, with strigose and some loose hirsute pubescence : leaves thickish; 

 upper simply and lower twice pinnatijid ; the lobes mostly lanceolate and acute : 

 sterile heads commonly short-pedicelled : fruit mostly solitary in the axils 

 below, rugose-reticulated, obtusely short-pointed, either wholly unarmed or with 

 four short either blunt or acute tubercles. From the Saskatchewan to Texas 

 and westward across the continent. 



29. FRANSERIA, Cav. 



Ours are herbaceous, with chiefly alternate leaves, and the spines of the 

 fruiting and 1 to 2-flowered involucre comparatively few. 



# Fruiting involucre seldom over a, line long, in the same plant bearing either 

 1 or 2 flowers. 



1 . F. tenuifolia, Gray. Erect, 1 to 5 feet high, leafy to the top, hispid, 

 variously pubescent, or glabrate : leaves mostly 2 to 3-pinnately parted or dis- 

 sected into narrowly oblong or linear lobes, the terminal elongated : sterile 

 racemes commonly elongated and paniculate : fertile heads in numerous glom- 

 erules below, in fruit minutely glandular, usually 2-flowered, armed with 6 

 to 18 short and stout incurving spines, their tips almost always hooked, and 

 an excavated cartilaginously bordered areola above each. PI. Fendl. 80. 

 From Colorado to California, Texas, and southward. 



* * Fruiting involucre 3 or 4 lines long at maturity, and longer stout or broad 

 spines : stems low. 



2. F. Hookeriana, Nutt. Diffusely spreading from an annual root, freely 

 branched, hirsute-pubescent or hispid : leaves of ovate or roundish outline, 1 to 

 3 inches broad, and bipinnatiftd, or the upper oblong and pinnatifid: sterile 

 racemes solitary or paniculate : fruiting involucre armed with fiat and thin 

 lanceolate-subulate smooth and glabrous long and straight spines, \-fiowered. 

 From the Saskatchewan to Texas and westward across the continent. 



3. F. discolor, Nutt. A foot or less high, erect from perennial slender 

 creeping root-stocks : leaves canescently tomentose beneath, green and glabrate above. 

 interruptedli/-pinnat(fid, oblong in outline, comparatively large, the lowest often 

 6 inches long ; the lobes usually short and broad : sterile racemes commonly 

 solitary : fruiting involucre 2-flowered, canescent, armed with rather short conical- 

 subulate very acute and straight spines. Plains, Nebraska to Wyoming, Colo- 

 rado, and New Mexico. 



4. F. tomentosa, Gray. A foot high, rather stout, erect, from an appar- 

 ently perennial base, canescent with a dense sericeous tomentum: leaves very white 

 beneath, cinereous above, pinnate/ 1/ 3 to 5-cIeft or parted; the terminal division 

 large, oblong or broadly lanceolate, serrate ; upper lateral similar but smaller ; 

 lowest commonly very small and entire: fruiting involucre 3 lines long, 2- 

 fiowered, nearly glabrous ; the short spines conical -subulate, very acute, and the 

 very tip usually uncinate-incurved. PI. Feudl. 80. Along streams or river- 

 beds, Kansas and E. Colorado. 



