MOKOPETALOUS EXOGENOUS PLANTS. M7 



flowers; achcnia short, 4-sided, crowned with a cup-shaped 

 toothed pappus.— Perennial sparingly branched 7/e?-^5, with 

 alternate undivided 3-5-ribbed leaves, and large heads 

 terminating the peduncle-like summit of the stem or 

 branches ; rays red, purple, or white. 



* Eays elongated, purple or white. 



E. ANGUSTIFOLIA, DC. Hirsute; stem simple; leaves 

 lanceolate, entire, 3-ribbed ; the lowest tapering into a long 

 I)etiole; scales of the invohicre imbricated in 2-3 row's ; 

 rays 12-15, narrow, pale purple. Stem l°-3° high ; lowest 

 leaves ^° long. 



RUDBECKIA, L. 



Heads many-flowered; the ray-floicers neutral ; those of 

 the dislc tubular, perfect ; scales of the involucre in about 

 two rows, leafy, spreading ; receptacle conical or cylindri- 

 cal ; the chaff not rigid, and mostly shorter than the disk- 

 flowers ; aclienia smooth, angled, truncated; 2^^ppus a 

 narrow border, or none. 



* Disk ovate or globose. 



t Leaves undivided ; stern simple oi- spainngly branched. 



R. HiKTA, L. Hirsute ; stem and hranclies naked at the 

 summit ; leaves 3-ribbed, lanceolate or oblong, serrate, the 

 upper ones sessile, the lowest narrowed into a petiole; 

 disk roundish, purplish brown ; chaff of the receptacle 

 acute, hairy at the apex ; appendages of the style subulate. 

 Stem rigid, l°-2° high ; rays longer or shorter than the 

 involucre. 



tt Leaves divided ; stem panicvlatdij or corymbosely branched. 



R. TRILOBA. Stem much branched, rough hairy; 

 lower stem-leaves 3-lobed, the upper sessile, simple, en- 

 tire ; heads small, numerous ; scales of involucre narrow- 

 lanceolate, shorter than the rays ; dish almost black ; chaff 

 of receptacle awl-pointed, smooth, as long as the flowers. 



