1921] NATURAL SCIENCES OF PHILADELPHIA. 487 



Our species would be P. angusiifolius caudatus (Heller) Rydb., 

 but that seems to be too inconstantly distinguishable to be con- 

 sidered as more than a form.*^" 



Corolla coerulean-blue, with violet-pink lines within on anterior 

 side' Flowering in May. 



Sandy prairies, extreme northwestern (''Panhandle" region of) 

 Oklahoma; Upper Sonoran Zone (at altitudes above 3,000 feet). 

 Ranges through the High Plains from North Dakota and eastern 

 Wyoming to northwestern Oklahoma and northern New Mexico. 



Oklahoma. Beaver: Knowles, Stevens 323 (M, U). Cimmar- 

 on: Doby, Stevens 508 (M, U). 



5. Penstemon fendleri Torr. & Gray. 



FenstemoH fendleri T.*& G., in Pacific RaU. Rep. 2. 4: 168. pi. 5. 1855. On 

 ' 'the Pecos and Llano Estacado [Texas, Dr. W. L. Diffenderfer on Pope's 

 Expedition]." Type not seen, but description and illustration distinctive. 



Corolla blue, pinkish on tube externally, with sharpl}^ defined 

 violet-pink lines internally on both posterior and anterior lobes. 

 Flowering in April and May. 



Sandy or gravelly loam, frequently over limestone, on plains or 

 bluffs, most common on the Staked Plains of northwestern Texas, 

 entering extreme western Oklahoma, and crossing the escarpment 

 southward to Menard and Tom Green Counties, Texas; chiefly 

 Upper Sonoran Zone (at altitudes above 1,600 feet). Also in east- 

 ern New Mexico, v 



Oklahoma. Beaver: , Stevens 352 (M, U). 



Texas. Fisher: Grady, Shepherd (U). Garza: Post, Pennell 



10533 (M, T, Y). Hale: Hale Center, (T). Hall: Estelline, 



Reverchon (M). Martin: Stanton, Eggert (M). Menard: Men- 

 ard, E. J. Palmer 11881 (M). Mitchell: Colorado, E. J. Palmer 

 13796 (M). Nolan: Sweetwater, E. J. Palmer 13736 (M). Pot- 

 ter: Ady, Pennell 10547 (A, M, T, U, Y). Randall: Canyon, 

 Pennell 10540 (Y), 10540 (C, H, O, P, U, Y). Runntls: Ballinger, 

 Pennell 10509 (T, Y). Swisher: Tulia, Pennell 10538 (A, C, H, J, 

 J, L, M, O, S, T, U, Y). Tom Green: San Angelo, Pennell 10486 

 (A, C, H, K, M, T, U, Y). 



g. Penstemon albidus Nutt. 



Penstemon albidus Nutt., Gen. PI. N. Am. 2: 53. 1818. "Hab. On the plains 

 of the Missouri, common, from the confluence of the River Platte to the 

 Mountains." Type seen in Herb. Academy of. Natural Sciences of 

 Philadelphia. 



6 See discussion in Contrib. U. S. Nat. Herb. 20: 362. 1920. 



