r 



ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI 



203 



Pastinaca saliva, Cicharium Intybus, Marrubium milgare, 

 Melissa officinalis, Nepeta Cataria, Fagopyrum esculentum, 

 Cannabis saliva, Humulus Lapulus, Asparagus officinalis, 

 H emerocallis fulva, Agrostis alba, Avena saliva and Phleum 

 pralense. 



Phenology. 



Geographical position, especially latitude, determines 

 e nature of the plant growth and the flowering and 



seasons 



As 



as well as other phenological phenomena* 



by De Candollct by experiments with both herba 



and woody plants, vegetation is more powerfully o: 



tly acted upon by the rising spring temperature ii 



TABLE L. 



MONTH 



Fruit 



March 

 April . 

 May. . 

 June . . 



July 



August 



September 

 October. . . 

 November. 





24 

 134 

 334 

 338 

 395 

 384 



229 

 59 

 14 









 50 

 141 

 223 

 341 

 437 

 262 

 45 



SPECIES FLOWERING AND FRUITING, BY MONTHS. 



higher than in lower latitudes. Subordinate, but of greatest 

 local influence, is physiography since indirectly, in determin- 

 ing the nature of the associations, as well as directly, it modi- 

 fies the temperature and the humidity of air and soil, the air 

 currents, and the intensity and amount of light together with 

 the chemical and physical conditions, including color, of the 

 soil. Each of these factors plays a part in the bringing about 



henological phenomena 

 most important. However 



heat alone the earlier 



date of flowering can not be ascribed. A 

 is yielded by the agaves of the island Lesir 

 which did not flower during 1889, something 



& 



♦ Schwendener, S. U. Ueber die periodischen Erscheinungen der 

 Natur insbesondere der Pflanzenwelt. Zurich. 1856. 



t De Candone, A. Des Effets differents d'une mgme Temperature 

 sur une meme EspSce au Nord et au Midi. Compt. Rend. 80. 7 Je. 1875. 



/ 



