1921] NATURAL SCIENCES OF PHILADELPHIA 489 



predominantly plants of open or of shade. Both however, 

 are frequently intermixed. One has corolla white or pale-pink, 

 with relatively wider throat, the pedicels and peduncles shorter so 

 that the thyrsus is more congested, and the leaves broader; this, 

 the prevalent form, is the plant called by Heller P. cobaea and by 

 Small P. helleri. The other has corolla darker, frequently bright 

 pink-red, with narrower throat more glandular within, the ped- 

 uncles and often fewer pedicels longer so that the thyrsus is more 

 lax, and the leaves frequently narrower; this would be typical P. 

 triflorus. In both the corolla has conspicuous deeper pink lines, 

 especially on the anterior side. However, field-study convinces 

 me that no real distinction of these trends can be made. All are 

 well shown in my series from Kerrville, Texas. Flowering from 

 March to May. 



Thin calcareous loam, gravelly or rocky places, common on the 

 hills of the Edwards Plateau, less frequent in the Lampasas and 

 Concho countries; lower Sonoran Zone (at altitudes from 500 to 

 2,000 feet). From Lampasas and Tom Green to Bexar and Valverde 

 Counties, central Texas. 



Texas. Bexar: Beckmann, Pennell 10407 (T, Y); Camp Stan- 

 ley Jnc, Pennell 10409 (Y). Burnet: Marble Falls, Bray 109 (Y). 

 Cooleman: Talpa, Pennell 10515 (Y). Comal: Bracken, Groth 23 

 (U). Crockett: Ozona to Devils River, Hanson 516' (U, Y). Gil- 

 lespie: Half-Moon Mt., Jermy 830 (M). Kendall: Boerne, Pennell 

 10415 (O, Y). Kerr: Kerrville, Heller 1610 (A, M, U, Y), 1654 

 (A, U, Y), Pennell 10377 (A, H, M, U, Y), 10380 (C, J, L, Y), 

 10382 (Y), 10397 (Y) 10398 (Y), 10399 (Y), 10400 (K, Y), 10402 

 (T, Y); Lacey's Ranch; Turtle Creek. Menard, Menard, E. J. 

 Palmer 1 1865 (M) . Real : Leakey, Lea (U) Tom Green : San Angelo, 

 Pennell 10500 (A, C, H, M, T, U, Y). Travis: Glen Rose, Hill (U). 

 Uvalde: Con Can, Sabinal, E. J. Palmer 10221 (Y). 



9. Penstemon cobaea Nutt. 



Penstemon cobaea Nutt., in Trans. Am. Phil. Soc. II. 5: 182. 1837. "Hab. 

 In the sterile and denudated portions of the prairies of Red River [Ark- 

 ansas Territory], in calcareous soil." Type seen in Herb. Academy of 

 Natural Sciences of Philadelphia. 



Corolla white or pale violet-purple, irregularlj- lined with violet; 

 probably frequently somewhat darker, as the type is described as 

 "bluish-purple." Flowering in April and May. 



^ Corolla also with short hairs on the anterior side. 



