142 BOTANICAL GAZETTE [FEBRUARY 
Ill., I was curious to ascertain whether this peculiarity was true for 
this locality, being aware that many beds of the Niagara limestone 
on which the plants were growing are magnesian, and have been used 
in the manufacture of hydraulic cement, the carbonate of magnesia 
sometimes exceeding 40 per cent. Consulting the Geological Survey 
of Illinois,? it was found that Frank H. Bradley, the writer of the 
chapter on the geology of Will county, in which the ledge is situated, 
describes the building stones of Joliet and Lockport as “‘a fine grained, 
clinking, magnesian limestone.” There can therefore be little ques- 
tion about the preference of the plant in this locality. 
I have met with the variety odlongifolium but once before, having 
collected it in 1873 near Kankakee, II]., where the same limestones 
occur. Outcrops of rock were frequent along the road by the side of 
which the plants grew, though the memorandum with the specimens 
_ does not say they were taken from the rocks. They were also from 4 
locality where the beds, according to Professor Bradley, “apparently 
correspond with those quarried at Joliet.”3 The plants may safely be 
said to show their preference here also. 
It was intimated above that the specimens at Lockport closely 
resembled the var. maximum Holl. & Britton, though this variety 1s 
assigned to California only. The stems are tall for the species, being 
3-4.5°" high, ascending to nearly erect from a short decumbent best 
The leaves are lanceolate to lance-oblong, 3-5 long by 5-12" wide, 
acute or acutish, as long and wide as those figured in pi. 64, fi: » 
of Hollick and Britton’s article, but not quite so lanceolate, tapet- 
ing from the middle rather more than from the base. The large 
white flowers have petals ro—-12™™ long ; the ripened capsule is about 
15 long, half or slightly more than half covered by the calyx. babes 
plants are much more like fig. 2 of this plate than p/. 63, which elt 
the variety obongifolium. Robinson4 remarks on the var. maximum 
“Similar robust forms of C. arvense have been found on the St. is 
river, Wis. (Houghton) ; and N. Illinois at Joliet (Boott) and Dies 
(Vasey).” As the locality near Lockport is but six miles from jou 
the forms may be identical in both places. If deemed the variety 
oblongifolium, it is not easy to distinguish the Lockport plants ehier 
those figured as the variety maximum.—E., J. Hii, Chicago. 
? Rep. Ill. Geol. Surv. 4: 220. 1870. 
3 Rep. Ill. Geol. Surv. 4: 233. 1870. 
4 Synoptical Flora of N, America, I*: 231. 1897. 
