222 COMPOSITE. (COMPOSITE FAMILY.) 



2. B. SUbacaulis, Nutt. Rough-pubescent and somewhat hoary ; leaves 

 chiefly radical, clustered, sinuate-pinnatirid ; heads solitary on the peduncle-like 

 stem, or fow on the peduncle-like branches of the short and nearly leafless stem. 



East Florida and Georgia. May - August. Peduncle G' - 8' long. Leaves 

 3' long. 



34. PARTHENIUM, L. 



Heads many-flowered ; the ray-flowers 5, in a single row, short, obcordate, 

 pistillate; those of the disk tubular, 5-toothed, sterile. Anthers slightly united. 

 Scales of the involucre in two rows, ovate or roundish. Receptacle conical, 

 chaffy ; the chaff dilated upward. Achenia smooth, compressed, thick -mar- 

 gined. Pappus of two awn-like or roundish scales. Herbs. Leaves alternate. 

 Flowers white. 



1. P. integrifolium, L. Perennial; stem erect, simple, rough; leaves 

 undivided, ovate or oblong-ovate, serrate ; the lowest narrowed into a long 

 petiole ; panicle dense, corymbose ; involucre hoary ; pappus minute, awn-like. 



Dry soil among the mountains, Alabama, and northward. August. Stem 

 1 - 2 high. Lowest leaves 4' - 6' long. Rays conspicuous. 



2. P. Hysterophorus, L. Annual, pubescent ; stem diffuse ; lAves 

 pinnatifid, with linear toothed lobes ; heads loosely panicled ; scales of the pap- 

 pus oval. Waste places, East and South Florida, and westward. 



35. IVA, L. 



Heads few- or many-flowered; the flowers all tubular; the marginal ones 

 (1-5) with a short corolla, pistillate and fertile; the central ones 5-toothed, 

 sterile. Anthers nearly distinct. Scales of the involucre 3 - 5, in a single row, 

 oval or obovate, distinct or partly united, or 6 - 9 and imbricated. Chaff of the 

 small receptacle linear or spatulate. Achenia biconvex, obovate. Pappus none. 



Branching herbs or shrubs, with opposite or (the upper) alternate mostly 

 fleshy leaves, and small axillary nodding heads of whitish flowers. 



* Scales of the involucre 3-5, in a single row. 



1. I. frutescens, L. Shrubby; leaves lanceolate or oblong, sharply 

 toothed -serrate, 3-ribbed, smoothish ; scales of the involucre 5, orbicular ; fertile 

 flowers 5. Saline marshes, Florida, and northward. Aug. and Sept. Shrub 

 4 - 8 high. 



2. I. microcephala, Nutt. Annual, rough with rigid appressed hairs ; 

 stem slender, much branched ; leaves narrow-linear, entire ; heads minute, 6 - 

 12-flowered ; scales of the involucre 4 - 5, obovate, ciliate ; fertile flowers 1-3. 



Dry barren soil, Florida to South Carolina. Aug. and Sept. Stem l-2 

 high. 



* * Scales of the inwlucre 6-9, imbricated in 2-4 roics. 



3. I. imbricata, Walt. Somewhat shrubby, smooth ; leaves fleshy, lance- 

 olate, the lower ones slightly serrate and 3-ribbed, the upper alternate and entire ; 

 heads many-flowered ; outer scales of the involucre orbicular ; the inner obovate, 



