279 3 
used by Nuttall, Tuckerman, in the same year, changed it to 
Oakesia, in honor of Dr. Oakes (O. Conradit Tuckerm., Hooker's 
Lond. Journ. Bot. 1842). 
In the meantime Dr. Torrey and Dr. Gray had critically 
studied the plant in this country from fresh specimens, and they 
both became convinced that the new species agreed in all impor- 
tant characteristics with Corema alba, and accordingly in 1842 Dr. 
Torrey changed the name to C. Conradii (C. Conrada Torr.; Loud. 
Arb. Brit. 1092. 1842), and it has since remained under that 
genus. 
We have, therefore, in the genus Corema two species ; the one, 
alba, confined to Portugal and Azores; the other, Cenradit, found 
only along the eastern coast of the United States, in widely sepa- 
tated localities, from Newfoundland to New Jersey. 
Accepting the evolutionary idea of the origin of species, a 
puzzling question arises as to the genetic relationship between 
these two species, their geographical distribution being difficult 
to reconcile with the idea of a common origin. | 
The morphology of the two has already been carefully studied 
and described ; their comparative anatomy, however, has not been 
considered. In view of the importance now given to anatomical 
characteristics in plant classification, the comparative anatomy of 
these two plants has been an interesting study, and it is the purpose 
of this paper to give some of the results of such a study. 
It has been impossible with the material available to follow the 
development-history of the tissues from their origin in the em- 
bryo, and the anatomy of the root has not been attempted, but a 
comparative study of the tissues of the fully developed stem and 
leaf has revealed some points of resemblance and difference from 
Which conclusions may be drawn as to relationship. 
The thick, deeply-grooved, evergreen leaf of C. a/a—the type 
of the genus—is about 1 mm. broad, and, including the short 
petiole, 7 mm. long. It somewhat resembles the small leaves of 
some Conifer. A cross-section of the mature leaf (Fig. Hl), 
under the microscope, shows the morphology to be strikingly dif- 
ferent from that indicated by the outward appearance. Instead of — A 
4 solid mass of tissue, as it seems to the naked eye, we find a flat 
leaf with its blades rolled under and the edges turned in so that 
