-t!'J THE PLANT COVERING OF OCRACOKE ISLAND. 



1 heodor Holm has rendered valuable assistance, and lie has kindly 

 furnished the drawings for figures Nos. 1 to 8, 17, and IS. The other 

 figures were drawn from nature hy the author. 



CLIMATE. 



The following data have been obligingly furnished ])y the United 

 States Weather Bureau. The observations were made at the Hatteras 

 Station, only a few miles northeast of Oeracoke. 



TEMPERATURE. 



Readings were taken in the shade.' The observations at Hatteras 

 cover a period of about twenty years. The average number of days 

 per annum with a temperature exceeding 6° C. (43° F.) is 365, Avhile at 

 Norfolk, Ya., the number is only 295. The sum total of temperatures 

 above 6° C. during the year averages 3,740.4:° C. (0,740° F.), which 

 is notably higher than the Norfolk figure of 3,359.4° C. (6,047.0° F.). 

 The normal mean temperature during the six consecutive hottest weeks 

 of summer is 25.0° C. (78.6° F.), as compared with the slightly higher 

 mean of 26.3° C. (79.3° F.) at Norfolk. 



The normal annual temperature is 16.3° C. (61.4 F.), as comimred 

 with 14.8° C. (58.7° F.) at Cape Henry, Virginia, 15.0° C. (59.0° F.) at 

 Norfolk, Va., and 17.2° C. (63.0° F.) at Wilmington, N. C. 



The normal monthly temperatures are as follows: 



January . 

 February 



March 



April 



May 



June 



Degrees C. , Degrees P. 



July 



August . .. 

 September 

 October . . 

 November 

 December 



The normal daily range of temperature for the whole year amounts 

 to 6.3° C. (11.3° F.),as compared with 8.2° C. (14.7° F.) atCapellenry, 

 8.8° C. (15.8° F.) at Norfolk, and 9.6° C. (17.3° F.) at Wilmington. 



The normal dail}^ ranges for each month are as follows : 



January . 

 February 



March 



April 



May 



June 



Degrees C. Degrees F. 



July 



August 



September 

 October . . . 

 November 

 December . 



5.1 

 5. 3 



10.0 

 9.3 

 9.6 

 10.2 

 11.3 

 12.8 



' Consequently they do not represent the temperature to which most of the vege- 

 tation is actually exposed, being subject to insolation during the hours of sun- 

 shine. They are chiefly valuable for purposes of comparison with other climates. 



