NortH Haven Sanp PLarins 585 
Ambrosia artemisiaefolia L.. Common ; small plants found on both 
tracts 
Achillea Millefolium L. Frequent. 
Chrysanthemum Leucanthemum L. Frequent. 
} Artemisia caudata Michx. Common, especially at North Haven, 
-where it grows with Rubus procumbens and Andropogon 
scoparius. 
PART II: STRUCTURE OF PLANTS EXAMINED 
Considerable attention has been given to the structure of the 
leaves and stems of plants, for it is in them that the most striking 
modifications have taken place to prevent a loss of moisture 
through transpiration. The plants of the Arabian desert, be- 
tween the lower Nile and the Red Sea, have been studied by Vol- 
kens, who has published an elaborate work* on this subject 
in its ecological relations. Schimper figures the structure of 
certain leaves and stems in his Pflanzen-geographie.t More recently 
Kearney has recorded the anatomy of the leaves of some of the 
plants of the North Carolina strand { and explained the ecoiog- 
ical significance of the structures. This line of research is car- 
ried still farther by the same author in his report on a botanical 
Survey of the Dismal Swamp region.§ In 1899 Mr. Thomas 
A. O’Brien in manuscript interpreted the structure of Spartina 
_ cynosuroides, Carex Muhlenbergii, Cyperus filiculmis and Poa com- 
pressa. But little attention has been paid to the root structures 
| of plants in relation to environment. The roots of many grasses 
and sedges have been studied by Mr. Theodor Holm, who has 
*Volkens, G. Die Flora der aegyptisch-arabischen Wiiste. 156 pp. 78 fi. 
Berlin, 1887. 
+ Schimper, A. F. W. Pflanzen-geographie auf physiologischer Grundlage. 876 
PP. 502 f.+ 4 maps. Jena, 1898. 
{ Kearney, T. H. The plant covering of Ocracoke Island: a study in the ecol- 
ogy of the North Carolina strand vegetation. Contr. U. S. Nat. Herb. 5: 261-319, 
J. 3&-50. 1900. 
4 Kearney, T. H. Report on a botanical survey of the Dismal Swamp region. 
Contr. U.S. Nat. Herb. 5: 321-550, p/. 66-76+ f. 51-85. 1901. 
O’Brien, T. A. The ecological structure of four native xerophytes. Manu- 
Script presented as a graduating thesis, Sheffield Scientific School of Yale University, 
I 
