OF ARTS AND SCIENCES : JUNE 11, 1867. 331 



foliis spathulatis oppositis, altero rninore ; stipulis majusculis hyalino- 

 scariosis ; floribus in axillis cymoso-congestis. 



Achyrontchia Cooperi. — In dry sand, Mohave River at Camp 

 Cady, Dr. J. G. Cooper, June, 1861. In Arizona or Sonora, A. B. Gray. 

 — Stems spreading from the slender root, 2 or 3 inches long; glabrous, 

 as is the whole plant. Leaves thickish and veinless, the larger of each 

 pair from a quarter to half an inch long, its fellow barely half as large. 

 Stipules interpetiolar, one on each side, orbicular or ovate, nearly 

 entire, silvery-scarious. Flowers in dense subsessile clusters, bright 

 silvery-white from the scarious calyx-lobes and stipular bracts, these 

 lobes about half a line long, at first longer than the tubinate calyx-tube, 

 which at maturity considerably exceeds them and becomes cylindra- 

 ceous and thickened in the manner of Scleranthus. The firm texture 

 and thickening of the tube extends into the axis of the broad and plane 

 oval or orbicular lobes for nearly one third of their length, making a 

 strong herbaceous, or at length more indurated, callosity in the base 

 of each ; all the rest is purely scarious, and without a vestige of midrib. 

 The filaments are very short and delicate, with their broadish bases 

 contiguous : if any arrangement can be traced it is, perhaps, that they 

 are single before each calyx-lobe, and in pairs before each sinus. The 

 fertile stamen is before a calyx-lobe ; and one flower out of many 

 examined apparently bore two anthers. The ovules appear to be 

 truly anatropous, on very short funiculi. But in the seed the chalaza, 

 as in Pollichia, is very much nearer the pointed hilar extremity, with 

 which it is connected by a delicate short rhaphe ; the seed is straight 

 and somewhat edged on that side, rounded above on the other ; the 

 thinnish testa delicately lineate ; the slender embryo nearly the length 

 of the seed. The very thin utricle bursts irregularly, at least when 

 the seed is extracted. — This curious little plant confirms the judgment 

 of Bentham and Hooker in retaining Pollichia with Paronychia and 

 its nearest allies, notwithstanding the geminate ovules. With the aspect 

 somewhat of Paronychia polygonifolia and the like, and a calyx which 

 Siphonychia somewhat resembles, this combines the geminate erect 

 ovules, one fertile the other sterile, and the straight seed and straightish 

 embryo of Pollichia. It is most peculiar in the remarkably silvery- 

 scarious calyx-lobes, and in the numerous sterile filaments or staminodia. 

 To separate entirely from the Caryophyllacece these plants, along with 

 Scleranthus and the other exstipulate genera, while leaving Queria, 

 Sphcerocoma, and the Polycarpece generally, requires narrow and devi- 

 ous, and probably at length impracticable distinctions. 



