116 University of California Publications in Botany. IT OL - 3 



TRIBE 4. AMBROS1EAE. RAGWEED TRIBE. 



35. IVA L. 



Ours coarse herbs and low shrubs with thickish alternate (or 

 the lower opposite) leaves and small nodding heads of greenish- 

 white flowers. Receptacle with chaff-like linear or spatulate 

 bracts. Marginal flowers of the head pistillate, 1 to 5 in number, 

 their corollas tubular or none. Disk-flowers perfect, with 5-lobed 

 funnelform corolla and undivided style. Anthers almost distinct. 

 Achenes somewhat flattened, glabrous. 



Involucral bracts united into a cup: stems herbaceous 1. 7. axillaris. 



Involucral bracts distinct: stems suffrutescent 2. 7. Hayesiana. 



1. I. axillaris Pursh., Fl. 743 (1814). POVERTY- WEED. 

 Herbaceous perennial with creeping rootstocks, 1.5 to 5 dm. 



high: stems many, erect from a mostly decumbent or prostrate 

 base: herbage pubescent or glabrous: leaves sessile, entire, nar- 

 rowly obovate varying to lanceolate or linear, 1 to 3 cm. long: 

 heads solitary in all the upper axils, short-peduncled, surpassed 

 by the leaves : bracts of the involucre united into a lobed or 

 merely toothed cup 3.5 mm. high. 



In saline or alkaline soil from Southern California (coast of 

 San Diego Co., Coahuilla Valley, Colton, Bear Valley, Cushen- 

 berry Springs, Antelope Valley, Ventura Co., Panamint Mts.) 

 to British Columbia and Nebraska. 



2. I. Hayesiana Gray, Proc. Am. Acad. xi. 78 (1876). 



Stem suffrutescent, branched from the base, the ascending 

 branches 6 to 9 dm. high : herbage strigose-puberulent or nearly 

 glabrous : leaves spatulate-oblong or linear, narrowed to the base, 

 obtuse, entire or rarely with one or two short teeth, 3 to 6 cm. 

 long, 6 to 12 mm. wide, the upper ones lanceolate and slightly if 

 at all surpassing the heads: involucral bracts about 5, distinct, 

 roundish. 



Brackish or alkaline soil of western San Diego Co. and south- 

 ward: near Warner's Ranch, Oct. 4, 1858, Suit on Hays; Tia 

 Juana Wash, Abrams, no. 3514; Elida, Lower California, Dr. 

 Veitch; Socorro and Canon de Gato, Lower California, Brande- 

 gee; Cedros Island, Anthony, no. 41. 



