426 THE SAPINDALES 



The stimulation of fertilization results in a green wing-like 

 outgrowth on each of the ovaries that assist at first in the manu- 

 facture of food for the embryo and later becomes a dry, mem- 

 branous organ for seed distribution. This fruit, known as a 

 schizocarp or samar, is at first partly loosened from its support 

 and remains attached only by a small stalk (Fig. 319, B), which 



FIG. 319. Fruit of the maple: A, mature fruit of red maple (Acer 

 rubrum). B, schizocarp of Norway maple. The fruit split in half is still 

 attached to the receptacle by delicate stalks. 



requires a rather strong wind to snap it. Thus the fruit is 

 freed under conditions that will result in the widest dissemina- 

 tion of the seed. The development of the chlorophyll-bearing 

 tissue in immature fruits to assist in' the work of food produc- 

 tion is an economical arrangement of tissues often to be seen. 

 It is noteworthy that these green fruits are often protected by 

 bitter, acrid juices and poisonous properties that finally give place 

 to attractive flavors, odors and colors, variations that are of 

 considerable assistance to seed protection and distribution. 



Many of the members of this order contain acid or poisonous 

 juices, as in the scarlet fruit of the sumac, which were a source 

 of acetic acid to the early settlers of this country, or poisonous 

 oils, as in the poison ivy or poison oak (Rhus radicans) and the 

 poison sumac (R. Vermx*). The former species is a climbing 



