30NCHUS LOBELIACEAE 405 



113 SONCHUS Tourn. L. Gen. n. 908. 

 Succulent herbs with leafy stems, alternate spinulosely or cili- 

 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-rootcd 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 auriculate 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. ASPER All. Fl. Fed. i, 322. 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 upper 

 clasping by an auriculate base, the auricles rounded: involucre glabrous, 

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

 fields and waste places. Naturalized from Europe. 



Order LII, LOBELIACEAE Juss. 



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

 nate leaves without stipules, racemose inflorescence and perfect 

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

 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 Ijud, 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 spHt 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 3-celled, introrsely dehis- 

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

 short tube. Ovary 3-celled, with placentae projecting from the 

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

 tire: stigma usually 3-lobed, girt with a rim of hairs. Ovules 

 and seeds mostly indefinitely numerous, small, anatropous. Em- 

 bryo 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 with tube 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. 



