284 ASTER FAMILY 



LEUCAMPYX Gray 1874 

 (Gr. leukos, white, ampyx, head-band, from the white-bordered bracts) 



Heads with white or cream-colored pistillate rays, disk-flowers yellow, 

 perfect, achenes wedge-shaped, incurved, flattened, pappus none ; receptacle 

 convex, with chaff, involucre hemispheric, the bracts imbricated in 2-3 

 rows, broadly white-papery at the top ; heads more or less corymbose ; 

 leaves alternate, 2-3-pinnately parted ; perennial. 

 Stems 1-2 ft. high; rays 10-12 mm. long; achenes 



black L. Newberryi 



LYGODESMIA Don 1829 MILK PINK 



(Gr. lygos, a pliant twig, desme, a bundle, referring to the rush-like stems) 

 Heads with pink or rose perfect strap-flowers, achenes terete, faintly 

 striate or angled, linear to club-shaped, pappus of white or whitish hair- 

 like bristles ; receptacle flat, without chaff, involucre of one row of main 

 bracts, with one or more shorter rows below; heads 3-12-flowered, usu- 

 ally terminal; leaves alternate, linear or scale-like; annual or perennial. 



1. Stems .5-1-5 ft. high, perennial; leaves mostly 



less than 3 in. long 



a. Heads 5-flowered; involucre 10-12 mm. high L. juncea 



b. Heads 6-10-flowered; involucre 20-25 mm. 



high L. grandifiora 



2. Stems 1-4 ft. high, annual; leaves 2-6 in. long; 



heads 8-9-flowered L. rostrdta 



MACHAERANTHERA Nees 1832 PURPLE ASTER 

 (Gr. machaera, sickle, anther a, anther) 



PI. 38, fig. 4. 



Heads with pale violet to purple pistillate rays, disk-flowers yellow, 

 becoming red or brown, perfect, achenes top-shaped, usually hairy, pappus 

 of hair-like bristles ; receptacle convex or flat, without chaff, involucre bell- 

 shaped, the bracts imbricated in many rows, usually spreading or reflexed ; 

 heads in corymbs or panicles ; leaves alternate, entire to pinnatifid, the lobes 

 often bristle-tipped ; annual, biennial or perennial. 

 1. Leaves entire to ciliate or spiny toothed 

 a. Bracts of the involucre with reflexed often awl- 

 shaped tips usually longer than the erect 

 basal portion ; flower clusters typically very 

 sticky-hairy 



(1) Stems 1-4 ft. high bearing usually many 

 heads ; leaves mostly lance-oblong, broad- 

 ened and clasping at the base; tips of 

 bracts mostly awl-shaped M. Bigelovii 



