FLOWERING PLANTS AND FERNS 0¥ ARIZONA 491 



forests, June to September. Western Canada, south to Texas and 

 Arizona. 



^Tiite loco. Plant showy in flower. The densely whitish pubescent 

 var. sericea A. Gray (0. sericea Nutt.) intergrades completely with the 

 greener, less-pubescent form. Like the latter, but with unusually 

 broad leaflets, is Aragallus knowltoni, described from a collection on the 

 San Francisco Peaks (Knoviton 44). 0. lambertii is one of the most 

 dangerous of the loco weeds, because it is eaten readily by horses, 

 cattle, and sheep, especially when grass is scarce, and the effects are 

 often fatal. It seems to be a pronouncedly habit-forming plant. 



41. GLYCYRRHIZA. Licorice 



Plant perennial, herbaceous; roots stout; stems tall, erect, very 

 leafy; leaves pinnate, the leaflets numerous, narrow; racemes many- 

 flowered, dense, spikelike; corolla whitish; alternate anthers smaller; 

 pods indehiscent, covered with hooked prickles. 



G. lepidota, which is a good soil binder but sometimes a bad weed on 

 fertile soils, contains in its sweet roots practically as much crude 

 glycyrrhizin as the imported licorice root of G. glabra L., which is used 

 in the manufacture of tobacco, confections, and fire extinguisher com- 

 pounds, as well as by druggists. 



1. Glycyrrhiza lepidota Pursh, Fl. Amer. Sept. 480. 1814. 



Apache, Navajo, Coconino, and Yavapai Counties, 2,200 to 7,000 

 feet, common along the Colorado River at Lees Ferry, May to July. 

 Ontario and New York to Washington, New Mexico, Arizona, and 

 California. 



42. HEDYSARUM. : - Sweetvetch 



Plants perennial, herbaceous; stems erect, leafy; leaves pinnate, the 

 leaflets numerous, finely punctate; flowers in axillary stalked racemes, 

 rather large and showy, the corolla rose purple; fruit (loment) flat, 

 several-j ointed, deeply indented above and below between the seeds, 

 the segments rounded, reticulate-veined. 



1. Hedysarum boreale Nutt., Gen. PL 2: 110. 1818. 



Hedysarum mackenzii Rvdb., N. Y. Bot. Gard. Mem. 1: 257. 



1900. Not of Richardson, 1823. 

 Hedysarum pabulare A. Nels., Biol. Soc. Wash. Proc. 15: 185. 



1902. 



Apache County to Coconino County, 6,000 to 7,000 feet, June. 

 Saskatchewan and Alberta, south to Oklahoma, Nevada, and northern 

 Arizona. 



The plants make excellent forage, but the species is too rare in 

 Arizona to be important. 



43. ALHAGI. Camelthorx 



An intricately branched, spiny, glabrous shrub; leaves small, re- 

 duced to a single leaflet; flowers numerous, in panicles of racemes, the 

 corolla purplish pink; fruit (loment) few-jointed, of 1 to 3 segments, 

 these not separating at maturity. 



72 Reference: Rollins, R. C. studies in the genus hedysarum in xorth America. Rhodora 42- 

 217-239. 1940. 



