138 Rhodora [Jut 
SISYMBRIUM BRACHYCARPON AND ALLIES. 
J. FRANCIS MACBRIDE. 
Dr. Ezra BRAINERD recently sent to the Gray Herbarium for exam- 
ination some specimens of a Sisymbrium collected both in Vermont 
and New York on the borders of Lake Champlain. These were 
evidently referable to S. canescens Nutt. var. brachycarpon (Richards) 
Wats. as treated in Gray's Manual, Seventh Edition. An examina- 
tion of the large amount of material now available has led to the con- 
clusion that this plant is specifically distinct from the mostly more 
southern S. canescens. The decidedly greener hue, more deeply 
segmented leaves, and remote simple viscid or glandular trichomes 
on the stems toward or quite to the base are characters that seem 
constant enough over a large area to justify its separation. The 
southern plant reaches its typical development in the southeastern 
states, and there is canescent with a soft rather coarse stellate pubes- 
cence, especially toward the base, the leaf-segments are short and 
rounded, and glandulosity, if present, is either confined to the upper 
portions of the plant or mingled with the pubescence, never standing 
out as simple distinct trichomes as in S. brachycarpon. 
Dr. Rydberg, Fl. of Col. 158, gives as a character of Sophia pinnata 
(S. canescens), “style obsolete," and in Bull. Torr. Club, xxxiv. 436, 
after describing Sophia magna, writes, *It was first mistaken for S. 
brachycarpa; but the style is evident although short." If we must 
delimit these species to this extent the above treatment is not correct 
but it does not seem probable that it will ever be necessary or feasible 
to sort out Sisymbrium specimens, that agree in every other respect, 
by this method. "The style is usually so minute that the question as 
to whether it is obsolete or evident is of little moment, especially since 
its relative development seems quite impossible of correlation with the 
more constant and certainly more striking differences indicated in the 
preceding paragraph. 
Both 5. canescens and S. brachycarpon undergo various modifications 
when they reach the prairie states and the Rocky Mountains. With- 
out any attempt to clear up the almost inconceivable confusion that 
involves the numerous segregate species proposed in the West, one or 
two facts appear reasonably evident and therefore are presented now. 
