152 



The Plant World 



suggested here, of making the equivalence of reciprocal crosses 

 a separate experiment. 



Finally, to show how appropriately this experiment repre- 

 sents the actual cross between the red and blue flower, dip the 

 red flower into boiling water a moment and then hold it in the 

 fumes cf ammonia or dip it into a dilute solution of ammonia or 

 of sodium hydroxide. Similarly take the blue flower and dip 

 it into the boiling water, and then into a dilute solution of 

 hydrochloric acid, in this way demonstrating that the difference 

 between the blue and red flower is due simply to the fact that 

 the cell-sap of the blue flower is alkaline, and the cell-sap of the 

 red flower is acid. 



THE PLANT SOCIETIES OF MONTEREY PENINSULA. 



(Continued.) 

 By H. B. Humphrey. 



Although by far the greater part of Monterey Peninsula 

 is covered with forest growth, there is an area varying in width 

 from a few yards to a quarter of a mile or more and extending 

 from Pacific Grove to the northern limits of the cypress forest, 

 a distance of approximately four miles, upon which neither 

 pine nor cypress has succeeded in establishing itself. A probable 

 explanation accounting for the absence of forest growth in this 

 open district may be found in the fact that from Point Pinos to 

 Cypress Point all vegetation is far more directly exposed to the 

 prevailing severe winds that beat in from the open ocean; while 

 at Pacific Grove and Monterey, situated as they are upon the 

 protected shores of Monterey Bay, the pines and other trees may 

 and do encroach very closely upon those plants that characterize 

 the shore formation. 



In this open area occur the sand dunes, discussed to some 

 extent in a previous paper, the open meadow land, and the bog 

 areas, each peopled with plants whollv or quite peculiar to it. 

 And yet in all three one may find plants of the same species — 

 plebeian mesophytes — apparently as much at home in a bog as 

 when stationed upon the unstable crest of a dune. 



The entire forest floor, in some places to a depth of several 

 inches, is covered with organic detritus in every stage of decom- 



