sonchus LOBELIACE^ 405 



ately dentate leaves and middle-sized heads of yellow flowers. 

 Involucre campanulate, in age usually broadened and fleshy- 

 thickened at base, becoming conical. Achenes obcompressed, 

 without beak or neck or dilated disk. Pappus of very soft and 

 fine flaccid bristles, which fall more or less in connection, and 

 commonly one or more stronger ones which fall separately. 



S. oleraceus L. Sp. 794. Fibrous-rooted annual : stem nearly simple, 

 1-10 feet high: lower leaves petioled, lyrate-pinnatifid, 5-10 inches long, 

 the terminal segment commonly large and triangular, the margins dentic- 

 ulate with mucronate or scarcely spiny teeth; upper pinnatifid, clasping by 

 an auriclate or sagittate base, the auricles acute : involucre 6-8 lines high : 

 achenes flat, longitudinally ribbed and transversely rugose. Common in 

 fields and waste places. Naturalized from Europe. 



S. aspeb All. Fl. Ped. i, 222. Stem often stout. 1-6 feet high, from 

 an annual root: leaves undivided, lobed or pinnatifid, spinulose-dentate ; 

 the lower spatulate to lanceolate, more or less distinctly petioled; the up- 

 per clasping by an auriculate base, the auricles rounded : involucre glab- 

 rous, about 6 lines high : achenes smooth, 3-nerved on each side. Common 

 in fields and waste places. Naturalized from Europe. 



Order LII, LOBELIACE^ Juss. 



Herbs, or rarely shrubs, with usually milky acrid juice, alter- 

 nate leaves without stipules, racemose inflorescence and perfect 

 5-merous flowers. Calyx adnate to the whole or the lower halt 

 of the ovary, the limb cleft to the ovary into 5 lobes. Corolla 

 inserted just where the calyx becomes free from the ovary, its 

 lobes valvate or induplicate in the bud, commonly deeper cleft 

 or completely split down between two of the lobes, the cleft 

 mostly on the upper side in the open flower but becoming so 

 by a twist; in the early bud the split looks toward the bract; 

 the lobes sometimes disposed to separate from below upward 

 and the limb to be bilabiately irregular. Stamens inserted with 

 the corolla and mostly free; anthers 2-celled. introrsely dehis- 

 cent, firmly united around the top of the style into a ring or 

 short tube. Ovary 2-celled, with placentae projecting from the 

 axis, sometimes 1-celled with two parietal^ placentae. Style 

 entire : stigma usually 2-lobed, girt with a rim of hairs. Ovules 

 and seeds mostly indefinitely numerous, small, anatropous. 

 Embryo straight, in the axis of fleshy albumen. 



* Corolla cleft to the base on one side : capsule free at the apex. 



1 Lobelia Calyx-tube short : capsule many-seeded, 2-valved at the top. 



* * Corolla with a closed tube : capsule wholly inferior. 



2 Howellia Calyx-tube linear-clavate : capsule 1-celled, few-seeded. 



3 Laurentia Calyx-tube turbinate'or oblong, corolla wittTtube as long 



as the limb: capsule short, 2-valved at summit. 



4 Bolelia Calyx-tube very long: corolla tube very short: capsule very 



long, opening by 1-3 long fissures. 



