MisccUanies. 350 



Leaves all p etiolate ^ suborbicular,* obsoletely or obtuse repand, 

 dentate, and gradually diminishing in size, but preserving nearly 

 the same form, to the ends of the branches. 



Flowers small; the corollas not half the size of those of the 

 rhomboidea, and comparatively inconsj)icuous. 



The plant continues to extend its slender branches, fresh and green, 

 nearly all summer. They usually lie prostrate on the mud, and of- 

 ten strike root, after tlie manner of creeping, or radicating stems; 

 a circumstance, I venture to say, never observed in the other spe- 

 cies. Sometimes a young shoot, or proliferous stem, starts from 

 the end of the raceme of siliijues, after the fruit is full growm. 



The foregoing discriminating features of the plants in question will 

 probably be deemed sufficient; and are submitted with considerable 

 confidence in their accuracy. 



W. D. 



To the Editor of the American Journal of Science. 



2. On'XantJiite and its crystalline form, with a notice of Mineral 



r 



Localities ; by Lt. TV. W. Mather^ Assistant Prof, of Chem. and 

 Min, U. S. M, A, — Xanthite has been described as a new mineral 

 species by Dr. Thomson, from its chemical and some of its physical 

 characters.f I have now the pleasure to state, that it also differs in 

 its crystallographical characters, from any mineral species liitherta 

 described. Dr. Thomson describes it as a mineral of "a light gray- 

 ish yellow color, consisting of a congeries of very small rounded 

 grains, easily separable from each other, and not larger than small 

 grains of sand. These grains are translucent, and some of them indeed 

 transparent. The lustre of the transparent grains is splendent; that 

 of the translucent grains shining. The lustre is inclining to resinous. 

 The grains are rounded, but when examined with the microscope^ 

 they seem to consist of imperfect crystals. The texture before a 

 powerful magnifier seems fohated; but the grains are so small, that 

 it is not easy to make out its true texture with accuracy. Specific 



gravity, 3.201. , 



"Easily crushed to powder by the nail of the finger. It is there- 

 fore soft. It does not scratch calcareous spar. Infusible before the 

 blowpipe per se. Nor did it fuse along with carbonate of soda." 



* I have occasionally noticed, at the base of the larger, lower leaves, a pair of 

 ^ohe$, exhibiting an effort as \i were to {orm jpinnaiifid leaves, 

 t Ann. of the Lye. of Nat. Hist, of New York, for April, 1828. 



