Plantce Lindheimcriance. 205 



squamosis in axillis ex tomento albo brevissimo setas spines- 

 centes albidas 3 — 5 gerentibus ; sepalis interioribus 8 ovato- 

 oblongis carinatis obtusis mucronatis ; petalis 10 obovato- 

 spathulatis obtusis integris concavis chartaceis (coccineis) ; 

 stylo longe supra stamina numerosissima exserto ; stigma- 

 tibus 7 acutiusculis erecto-patulis viridibus. — Granitic re- 

 gion about the Liano : flowers (in St. Louis) in May. — 

 Named after my friend Dr. F. Roemer, of the University of 

 Bonn, who was the first to explore the geology of Western 

 Texas, and brought the first specimens of this species. Sent 

 also in numerous specimens by Lindheimer. Heads 3—4 inches 

 high, \\-2\ inches in diameter, single, or mostly 3-5 or even 

 10 from the same base; ribs interrupted: areola? 4 — 8 lines 

 distant from one another : radial spines 5-12 lines long; lateral 

 spines longest: upper ones usually shortest ; central spine 10- 

 15 lines long. Flower open by day and night, for 4 or 5, and 

 in cool cloudy weather as much as 6 or 7 days, 2 inches long, 

 and one wide : petals 8- 9 lines long, 5 lines wide, stiff: bris- 

 tles on the tube 2-3 lines long. — The stiff and almost per- 

 gamentaceous petals are uninfluenced by sunshine or darkness 

 like those of most other Cactaceae. Several other northern 

 species most probably agree in this particular, as especially 

 C. coccincus and C. triglochidiaius of New Mexico ; while 

 other nearly related species have certainly diurnal flowers. — 

 C. coccineus differs by the more numerous ribs, more numer- 

 ous spines, larger and more crowded areolae, etc. C. -poly acan- 

 thus, Engelm. in Wisliz. Rep., has more numerous spines, 

 and ten ribs, C. enneacanthus, Engelm. 1. c, is larger with the 

 tubercles less distinct, ten ribs ; spines larger, angular. 



Cereus variabilis, Pfeiff., with its beautiful white noc- 

 turnal flowers, delighted our volunteers in their camps on the 

 lower Rio Grande. Young plants are procumbent, with 

 terete or rather clavate branches: adult plants several (3- 

 10) feet high, mostly triangular, with very long and stout, or 

 sometimes quite short spines. Fruit large, luscious, with red 

 pulp : seeds large, smooth, shining. 



JOURNAL B. S. N. H. 27 JA.N. 1850. 



