154 BRASSIACEAE. 



6. DITHYREA Harv. 



1. Dithyrea Wislizeni Engelm. In dry regions from Tex. and Colo, to 

 Utah and Ariz. — Alt. 4500-6000 ft. — Valley of the San Juan (Brandegee). 



7. PHYSARIA A. Gray. Double Bladder-pod. 



Pods deeply cordate at the base ; lower sinus almost as deep as the upper. 



1. P. didymocarpa. 

 Pods not cordate at the base or slightly so ; lower sinus none or very shallow. 

 Basal leaves or at least some of them more or less fiddle-shaped. 



Leaves of the decumbent flowering stems reduced ; terminal lobe of the basal 



leaves rounded or reniform, very obtuse, entire. 2. P, vitulifera. 



Leaves of the ascending flowering stems ample ; terminal lobe of the basal 

 leaves rhombic or ovate, obtuse or acute, sinuate. 3. P. Horibunda. 



Basal leaves oblanceolate or spatulate, acute, not fiddle-shaped, 2-4 cm. long. 



4. P. acutifolia. 



1. Physaria didymocarpa (Hook.) A. Gray. On dry hills from Sask. and 

 Alb. to Colo, and Utah.— Alt. 5000-7000 ft.— Bluffs north of La Porte; Ft 

 Collins; Ruxton; Durango; Mancos. 



2. Physaria vitulifera Rydb. In mountain valleys and caiions of Colo. — 

 Alt. 8000-10,000 ft. — Palisades; Idaho Springs; Grand Junction; headwaters 

 of Clear Creek; alpine ridges east of Middle Park; Bear Creek Caiion. 



3. Physaria floiibunda Rydb. In mountain valleys of Colo. — Alt. 5000- 

 9000 ft. — Plains and foot-hills near Boulder; Wolcott; Veta Pass; Golden, 

 Jefferson Co. ; Cimarron ; Sangre de Cristo Creek ; Clear Creek Canon ; 

 Hotchkiss; Eldora to Baltimore. 



4. Physaria acutifolia Rydb. On dry hills in Wyo. and Colo. — Alt. 5000- 

 10,500 ft. — Grand Junction; Ruxton Ridge; North Cheyenne Cation; Steam- 

 boat Springs. 



8. LESQUERELLA S. Wats. Bladder-pod. 



Ovary and pod stellate-pubescent. 

 Pods ovoid or ellipsoid. 



Pods distinctly compressed and acute at the apex. 

 Pods 6-8 mm. long ; plant usually over i dm. high. 



Basal leaf-blades broadly oval ; septum elliptic in outline ; style equalling 



the pod in length. i. L. Shearis. 



Basal leaf-blades oblanceolate to obovate ; septum ovate in outline ; style 

 much shorter than the pod. i. L. curvipes. 



Pods 3-5 mm. long ; plant i dm. or less high. 



Leaves narrowly linear-oblanceolate ; plant pulvinate. 3. L. alpina. 

 Leaves narrowly linear ; plant multicipital with a subterranean woody 

 caudex. 4. L. parvula. 



Pods not compressed above. 



Basal leaf-blades rounded or broadly spatulate. 



Stem-leaves small, generally less than i cm. long, linear-oblanceolate. 



5. L. prostrata. 

 Stem-leaves oblanceolate to obovate, 1-2 cm. long. 6. L. montana. 



Basal leaf-blades linear-oblanceolate. 7. L. arenosa. 



Pods globose. 



Stem very slender; stem-leaves oblanceolate, 1-3 cm. long. 



7. L. arenosa. 

 Stem stouter, strict ; stem-leaves linear, 2-6 cm. long. 8. L. argentea. 



Ovary and pod glabrous, globose. 



