182 BOTANICAL GAZETTE [SEPTEMBER 
ture are known in many other genera, which so far have been 
left intact. 
Anatomically our genus is not a very interesting one, but the 
structure has never been studied, and I thought that the following 
discussion of the vegetative organs might be of some interest from 
a comparative point of view. Some knowledge of the structure, 
especially since the material came from widely separated stations, 
may be of interest to students of plant societies, for it seems to me 
that many of the conclusions reached in the name of ecology are too 
superficial, so long as the plants themselves have not been studied 
thoroughly. 
ROOTS 
In our native species of Sisyrinchium the secondary roots are 
slender; they are soft and of a whitish color in S. californicum, but 
quite strong, and yellowish brown in the other species. In 
xerophyllum and S. grandiflorum the roots are almost villous from 
the dense covering of root hairs, while in the other species the roots 
are much less hairy. The epidermis is thin-walled, and inside this 
is an exodermis of a single stratum, whose cells are mostly pentago 
nal in cross-sections, and thin-walled in all the species except S. 
xerophyllum, in which the exodermis is very distinctly thickened. 
The cortical parenchyma contains no stereids, and is composed 0 
a compact, but thin-walled tissue; in S. montanum the cortex collapses 
tangentially, but remains solid in the other species, and contains 
deposits of starch except in S. calijornicum. The endodermis shows 
a very pronounced thickening of the inner cell walls, thus representing 
a U-endodermis, but is thin-walled in S. californicum. : 
The pericambium consists generally of a single layer of thin- 
walled cells (P, jig. 8), and is continuous; however, the followine » 
exceptions were noticed. In S. montanum (fig. 9) there is frequently 
a second stratum of pericambium to be observed outside some of the 
hadrome rays and this same condition occurs also in S. xerophyll we 
(fig. 10). Sometimes the pericambium becomes thick-walled, ” 
may be seen from jig. rz, which is of S. xerophyllum, and in which the 
cells outside the leptome are quite thickened in contrast to those sl 
side the hadrome. In these same figures of S. xerophyllum (fiss- 
10, IT) we notice also that the pericambium is not continuous, 
