104 POLYGONACEAE. 



Inflorescence glabrous, lax with spreading branches ; involucre 2-2.5 



mm. long. 30. E. salicinum. 



Inflorescence less compound ; branches and internodes short, mostly 



spreading. . 35. E. micro thecum. 



Leaf -blades linear, revolute. 36. E. Simpsonii. 



Dwarf depressed undershrubs, less than i dm. high, with heath-like leaves. 



37. E. contortum. 



IX. ANNUA. 



One species. 38. E. anmtum. 



X. VIRGATA. 



Leaves crowded on the ends of the short caudex ; blades abruptly narrowed at 



the base or subcordate. 39. E. racemosum. 



Leaves scattered on the fruticose branches ; blades tapering at the base. 



40. E. Wrightii. 

 XI. PEDUNCULATA. 



Perianth glabrous. 



Scapes and branches glabrous. 

 Peduncles erect or ascending. 



Perianth-lobes nearly equal and similar ; leaves glabrous. 



41. E. Gordonii. 

 Perianth-lobes very unequal and dissimilar ; leaves floccose beneath. 



Outer perianth-lobes dilated above; involucres about 1.5 mm. long. 



42. E. rotundifolium. 

 Outer perianth-lobes not dilated above ; involucres about 3 mm. long. 



43. E. tenellum. 

 Peduncles reflexed or deflexed. 44. E. cernuum. 



Scapes and branches villous or glandular, especially near the nodes. 



45. E. trinervatum. 

 Perianth glandular or pubescent. 



Scapes and branches glandular, especially near the nodes, not inflated. 



48. E. glandulosum. 

 Scapes and branches glabrous ;. upper portion of the lower internodes of the 



scape inflated. 



Accessory branches at the lower forks of the inflorescence many and nearly 

 as strong as the three main branches ; branches divaricate. 



46. E. fusiforme. 

 Accessory branches at the lower forks of the inflorescence none or few 



and small ; branches ascending. 47. E. inflatum. 



XII. DIVARICATA. 

 One species. 49. E. divaricatum. 



XIII. FOLIOSA. 

 One species. 50. E. salsuginosum. 



1. Eriogonum alatum Torr. In sandy soil from Neb. and Wyo. to Tex. and 

 Ariz. Alt. 4000-10,000 ft. Headwaters of Clear Creek and alpine ridges 

 east of Middle Park; plains and foot-hills near Boulder; Green Mountain 

 Falls; Sand Creek Pass; South Park; Williams' Canon, near Pike's Peak; 

 Sangre de Cristo Creek; Table Rock; Pagosa Springs; Thompson's Park, La 

 Plata Mountains; Spring Canon; Dillon Canon, near Trinidad; plains, near 

 foot-hills, Larimer Co. 



2. Eriogonum triste S. Wats. (E. alatum glabriusculum Torr.) In sandy 

 soil from Colo, to Tex.' and N. M. North Park ; headwaters of Clear Creek 

 and alpine ridges east of Middle Park. 



3. Eriogonum Jamesii Benth. On plains and hills from Kans. and Colo, to 

 Tex. and Ariz. Alt. 4000-9000 ft. Headwaters' of Platte River; Colorado 



