ASTERACEAE. 405 



of variously colored flowers. Involucre ovoid or globose, 

 its bracts imbricated in many series, tipped with a stout 

 spine. Receptacle flat, bristly. Corolla-tube slender, 

 the limb 5-toothed or 5-cleft. Achenes oblong or obo- 

 void, compressed or somewhat 4-angled, obliquely or 

 laterally attached to the receptacle. Pappus of many 

 slender scabrous bristles or scales or rarely none. 



1. C. melitensis L. (Star-thistle.) Erect, branching, 5-8 

 dm. high, cinereous-pubescent or when young somewhat woolly; 

 basal leaves lyrate-pinnatifid, those of the stem lanceolate, mostly 

 entire, narrowly decurrent; principal bracts with slender spines of 

 about their own length, spines pectinate-spinulose at base, inner- 

 most with spinescent tips; flowers yellow; pappus of very unequal 

 rather rigid bristles or squamellate. 



A common weed in waysides and fields. July-November. 

 Native of southern Europe. 



Tribe 11. MUTISIEAE. Perezia Tribe. 



Ours perennial herbs with subcoriaceous setulose- 

 ciliate alternate leaves. Involucral bracts imbricated. 

 Corollas 2-lipped, the outer lip 3-lobed, the inner 2-lobed. 

 Anthers caudate and with a long appendage at the apex. 



Represented with us by the single genus. 69. Perezia. 



69. PEREZIA Lag. 



Perennial herbs with mostly reticulated often setulose- 

 ciliate or spinulose leaves, and solitary cymose or panicu- 

 late middle-sized discoid heads of rose-purple white or 

 blue flowers. Involucral bracts imbricated in few- 

 several series, dry, chartaceous or coriaceous. Recep- 

 tacle flat, naked, rarely pilose or fimbrillate. Corollas 

 5-lobed and somewhat bilabiate. Achenes narrowed at 

 apex. Pappus of copious capillary scabrous rigid or soft 

 bristles. 



1. P. microcephala Gray. Tall, branching above, 1.5-2 m. 

 high, leafy; leaves oblong, the upper ovate, cordate-clasping, 8-12 

 cm. long, thin-coriaceous, minutely glandular-scabrous, veiny, 

 closely spinulose-denticulate; heads corymbose at the summits of 

 the paniculate branches, 12-15 mm. high; involucral bracts very 

 acute, coriaceous; flowers 10-15 in a head, their corollas 8-10 mm. 

 long, rose-purple. 



Frequent on the dry interior plains and foothills. July-August. 



