1883. } Botany. 1163 
Allen and determined to be amphibole. Klein has recently 
examined some crystals of w//manuite from Sardinia. The prin- 
cipal planes were those of the cube, which was striated as in pyr- 
ite, being due to the same cause, the repetition of pyritohedral 
edges. Pyritohedral and dodecahedral planes also occurred, The 
specific gravity was somewhat higher than usual, being 6.84. An 
analysis showed a mere trace of arsenic. e determined per- 
centages of nickel, sulphur and antimony agree closely with the 
formula, Ni (Sb, S). The crystals were imbedded in calcite— 
It has been found that almost all platinum ore is magnetic, and 
that no purification can be effected by means of a magnet. Even 
a weak magnet will attract a large percentage of platinum along 
with the iron in an impure ore. Experiments have shown, in- 
deed, that as much platinum as iron is attracted ——Go(d is re- 
ported as occurring in a Cretaceous limestone in Williamson 
county, Texas. It is supposed to have originally existed as an 
auriferous pyrite, by the decomposition of which the sulphur 
has been removed, the iron oxidized and the gold concentrated. 
BOTANY." 
Watson’s CONTRIBUTIONS To AMERICAN Botany, xI.— We 
have the pleasure of again noticing another of Mr. Watson’s fre- 
quent publications, this time a thick pamphlet of one hundred 
Pages, extracted from the Proceedings of the American Academy 
of Arts and Sciences (Vol. xvin). It bears date of August 15, 
1883, and contains descriptions of many new species. There is 
first a list of plants from Southwestern Texas and Northern Mex- 
ico, collected chiefly by Dr. E. Palmer in 1879-80, occupying 
nearly the whole pamphlet ; this is followed by five pages devoted 
to descriptions of some new Western species. ee 
The Commelinacez of the United States are revised in a foot- 
material in the Gray Herbarium, Twenty-five “species are recog- 
nized, as follows: 1. B. tenuis Griseb., Mexico; 2. B. prostrata 
pe alg ica; 4. B. scorpioides Lag., Mex.; 5. B. hirsuta Lag., 
S. Utah to Te E TrA W. 
ayes x., S. Cal. and Mex.; 8. B. eriopoda Torr., W. 
and New Mex. ; 9. B. trifida Thurber, W. Tex., New, Mex. and 
€X. ; 10. B, burkei Scribner, W. Tex. and New Mex. ; II. B. race- 
ing Lag, N. Y. and Pa. to Wis., Tex., Ariz. and Mex. [this is 
W A curtipendula Torr., of the manuals]; 12. B. bromoides Lag., 
By > t0 Ariz. and Mex. ; 13. B. havardi Vasey, W. Tex. Mag 
 hondrosivides Benth., Mex.; 15. B. litigiosa Lag., W. Indies ; 
£ 7 
| by Pror, C, E. Bessey, Ames, lowa. 
YOL, 
OL, XVII.—no, xI, 77 
