362 COMPO SITAE MATRICARIA 



CHRYSANtHEMUM 



numerous small linear to setaceous-subulate divisions: heads numerous, 

 crowded in a fastigiate cyme; involucre oblong, its bracts pale or some- 

 times fuscous-margined or wholly brownish: rays 4-6, 2-3 lines long and 

 broad, white to rose-color : receptacle at length elevated. Very variable, 

 perhaps as here defined includes several species. Common from Alaska 

 to California and across the Continent. 



72 MATRICARIA L. Sp. 890. 



Herbs with finely once to thrice dissected alternate leaves 

 and pedunculate heads of yellow flowers with white rays when 

 present. Heads small to rather large, radiate, or discoid and 

 homogamous by the absence of ligulate pistillate flowers. Re- 

 ceptacle conical or ovoid, rarely lower when young, without 

 bracts among the flowers. Achenes glabrous, 3-5-ribbed or nerved 

 on the face or sides, rounded on the back. Pappus none, or a 

 mere coroniform border. 



M. discoidea DC. Prodr. vi, 50. Glabrous annual : stems 4-18 inches 

 high diffusely branched, very leafy : leaves 2-3-pinnately dissected into 

 short linear acute lobes : heads numerous, all short-peduncled : bracts of 

 the involucre oval, with broad white scarious margins and green centre, 

 much shorter than the disk: receptacle high-conical: achenes oblong, 

 somewhat angled, with an obscure coroniform margin at the summit. In 

 yards and waste places Alaska to California and the Eastern States. 



73 CHRYSANTHEMUM L. Sp. 888. 



Perennial or annual herbs, with alternate dentate incised or 

 dissected leaves and large heads of both tubular and ligulate 

 flowers. Involucre hemispheric or depressed, its bracts ap- 

 pressed, imbricated in several series, the outer shorter. Recep- 

 tacle flat, convex or hemispheric, naked. Rays pistillate, fertile. 

 Disk-flowers perfect, their corollas with terete or 2-winged tubes 

 and 4-5-cleft limb. Achenes 5-10-ribbed, or nerved, terete, or of 

 the ray 3-angled. Pappus none or a scaly cup. 



C. Leucanthemum'L. Sp. 888. Glabrous or sparingly puberulent: stems 

 1-3 feet high, from a creeping perennial rootstock, simple or sparingly 

 branched : radical leaves ovate to spatulate, coarsely dentate or incised, 

 narrowed below to long slender petioles ; cauline spatulate, the upper grad- 

 ually narrower, becoming small and linear, pinnately dentate or incised, 

 partly clasping at base : heads long-peduncled, broad and flat : rays white, 

 an inch long: pappus none. Becoming common in meadows and waste 

 places. Naturalized from Europe. 



74 SOLIVA Ruiz. & Pay. Prodr. 113, t. 34. 



Small depressed herbs with mainly alternate petioled pinnately 

 dissected leaves and small heads of greenish flowers sessile in 

 the axils or forks of the branches. Heads discoid, heterogamous ; 

 the apetalous pistillate flowers most numerous ; a few hermaphro- 

 dite but mostly sterile ones with a short and thick 2-6-lobed corolla 

 in the centre. Involucre of 5-13 nearly equal bracts in not more 

 than 2 series. Receptacle flat, naked. Achenes obcompressed, 



