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 6 feet 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. PBANSEEIA, 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 

 I or 2 flowers. 



1 . F. termifoli a, 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 bipinnatifid, or the upper oblong and pinnatifid : sterile 

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

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

 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, 

 interrupt edly-pinnati 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, pinnately 3 to 5-cleft 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- 

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

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

 beds, Kansas and E. Colorado. 



