1896} BRIEFER ARTICLES 253 
here brought forward are by no means the most reliable. For the 
hispid pubescence is not always absent upon B. juncea, although always 
much less conspicuous than in B. Sinapistrum ; the trichomes, when 
present, being confined to the lower leaves and lower part of the stem. 
Furthermore, the siliques of B. Scnapistrum vary greatly in position, 
being sometimes subappressed and sometimes widely spreading, so 
that they are accordingly either erect or very oblique. As to the length 
of the fruit there is no great difference between the two species, but if 
a distinction can be made on this feature it would seem that the fruit 
of B. Sinapistrum rather than of B. juncea was in general the longer. 
On the other hand, several characters furnish very definite and con- 
stant differences. In the first place, B. juncea is a taller and much 
paler plant, having a distinctly glaucous stem and more or less 
glaucescent leaves, while B. Sinapistrum, at least as it occurs about Bos- 
ton, is never glaucous at all. Then in B. Sinapistrum the upper leaves 
are broadest near the rather abruptly contracted base, while in B. juncea 
ey are gradually cuneate at the base. But perhaps the most striking 
difference is in the fruiting pedicels, which in B. Sinapistrum are short 
and thick, being only about 4 or rarely 6" long, while in B. suncea 
they are much more slender and 6 to ro™ in length. The 
beak of the fruit in B. juncea is slender, subulate, and apparently 
always empty. In B. Stnapistrum, on the other hand, it is rather stout, 
decidedly ancipital, and commonly contains one seed. 
eae characters the plants in question - be readily dis- 
: , and when once recognized are not likely again to be 
oes B. juncea seems already to be the commoner species 
the “apt Boston. Its rapid distribution and establishment ° 
ca nb recalls that of Larhuca Scariola, on the more — 
fesive is . : Stsymbrium altissimum. The best illustration of 4. 
4 ok. 3 Duthie and Fuller in their Field and Garden Crops of 
ee roi ern Provinces and Oudh (plate 41).—B. L. ROBINSON, 
uiversity. 
A NEW MAMILLARIA. 
Sim : ia Brownii," n. sp. Glaucous, globose, 5 to g™ high, 
haa tubercles 20 to 28™ long, at first terete but later becom- 
more or less quadrangular at base, very broad and large, the 
1Thi s 
's plant will be Cactus Brownii to those who prefer the generic name Cactus 
