230 NORTH AMERICAN FLORA [VoLuME 34 
Dibothrospermum Knaf, Flora 29: 298. 1846. 
Trallesia Zumag. Fl. Ped. 1: 361. 1849. 
Akylopsis Lehm. Ind. Sem. Hort. Hamb. 1850: 3. 1850. 
Mostly annual glabrous herbs. Leaves alternate, once to thrice pinnatifid into narrow 
divisions. Heads solitary or corymbose, radiate or discoid. Involucre saucer-shaped to 
‘hemispheric; bracts in 2-4 series, somewhat imbricate, but usually of nearly the same length, 
oblong to elliptic, obtuse, scarious-margined. Receptacle conic, hemispheric, or subglobose, 
naked. Ray-flowers, if present, pistillate and fertile; ligules white; style exserted, with 
short truncate branches. Disk-flowers numerous, hermaphrodite and fertile; corollas yellow; 
tube cylindric or nearly so; throat campanulate; lobes 4 or 5, ovate or lanceolate; anthers 
with ovate obtuse tips; style included; branches short with truncate tips. Achenes usually 
asymmetric, with 3-5 ribs on the inner half, the back being nerveless. Pappus of a more 
or less developed crown or margin. 
Type species, Matricaria Chamomiilla L,. 
Heads radiate; disk-corollas 5-lobed; involucral bracts subequal. 
Receptacle hemispheric, or nearly so, rounded at the summit, solid; achenes 
3-ribbed on the inner side, rugose or muricate on the back and be- 
tween the ribs; plant inodorous. 
Bracts with white or light-brown scarious margins. 
Leaf-segments slender, not fleshy, elongate; stem erect; pappus- 
crown usually entire. 1. C. inodora. 
Leaf-segments short, fleshy, divaricate; stem usually diffuse; pappus 
distinctly toothed. 2. C. maritima. 
Bracts with dark-brown almost black scarious margins. 3. C. Hookeri. 
Receptacle conic, acute, hollow; achenes 5-ribbed on the inner side, smooth 
on the back and between the ribs; plant sweet-scented. 
Pappus a minute entire crown. 4. C. Chamomilla. 
Pappus a conspicuous fimbriate crown, as long as the width of the 
achene. 5. C. Courrantiana. 
Heads discoid; disk-corollas 4-lobed; receptacle conic. 
Involucre saucer-shaped; bracts in 2—3 series, subequal; receptacle hollow. 
Involucre 5-8 mm. broad; pappus-crown minute, entire. 6. C. suaveolens. 
Involucre 8-12 mm. broad; pappus-crown with a conspicuous lobe 
on each side. 7. C. occidentalis. 
Involucre hemispheric; bracts imbricate, in 3-4 series, the outer shorter; 
receptacle solid. 8. C. suffruticosa. 
1. Chamomilla inodora (L.) Gilib. Exerc. Phyt. 179. 1792. 
Matricaria inodora VL. Fl. Suec. ed. 2. 297. 1755. 
Chrysanthemum inodorum I1,. Sp. Pl. ed. 2. 1253. 1763. 
Pyrethrum inodorum Moench, Meth. 597. 1794. 
Tripleurospermum tnodorum Schultz-Bip. Tanac. 32. 1844. 
Dibothrospermum agreste Knaf, Flora 29: 299. 1846. 
Chamaemelum inodorum Vis. Osserv. Matric. 13. 1844.—FIl. Dalm. 2: 85. 1847. 
Trallesia matricarioides Zumag. Fl. Ped. 1: 361. 1849. 
A leafy annual; stem 2-4 dm. high, glabrous, striate, branched; leaves bipinnatifid, 3-6 
em. long, with linear-filiform, long and flaccid divisions, glabrous or nearly so; heads several, 
solitary at the ends of the branches; involucre saucer-shaped, 4 mm. high, 10-15 mm. broad; 
bracts in 2-3 series, subequal, linear or linear-oblong, obtuse, with white or light-brown searious 
margins; receptacle convex, obtuse; ray-flowers 15—25; ligules white, 7-10 mm. long, 2-3 mm. 
wide; style-branches truncate; disk-corollas yellow, 2.5 mm. long; tube equaling the cam- 
panulate throat; lobes 5, lanceolate; achenes 1.5—2 mm. long, dark-brown when ripe, oblique, 
with 3 strong ribs on the inner side, rugose on the back and between the ribs; crown of pappus 
well developed, usually entire. 
TYPE LOCALITY: Sweden. 
DiIstRIBUTION: Newfoundland to Pennsylvania and Ontario; Oregon and Idaho; adventive or 
naturalized from Europe. 
ILLUSTRATIONS: Reichenb. Ic. Fl. Germ. 16: pl. 985, f. I; Engl. Bot. pl.676; Fl. Dan. pl. 1936; 
Fl. Deuts. ed. 5. pl. 3047; Coste, Fl. Fr. f. 1948; Britt. & Brown, Ill. Fl. f. 3992; ed. 2. f. 4565. 
2. Chamomilla maritima (L.) Rydberg. 
Matricaria maritima V,. Sp. Pi. 891. 1753. 
Pyrethrum maritimum Smith, Fl. Brit. 901. 1800. 
Chrysanthemum maritimum Pers. Syn. Pl. 2: 462. 1807. 
