342 BOTANY OF CROP PLANTS 



micropyle. Endosperm is absent. The cotyledon leaves 

 are persistent until the root becomes of considerable size and 

 may be seen at the crown of the radish, lying flat against 

 the root. Each cotyledon leaf is oblong in outhne and 

 broadly notched at the tip. 



Geographical Distribution and Origin. — The common 

 radish is found growing wild in the temperate regions of the 

 Old World. It was introduced into this country by the 

 earlier settlers and here, as wherever it is planted, has 

 escaped from gardens, becoming in many instances a rather 

 common wayside plant. Radishes that run wild in this 

 manner produce a root that is slender and woody, possibly 

 reverting to the type from which it came. E. A. Carriere 

 held the opinion that our common garden radish has sprung 

 from Raphanus raphanisirum, the wild radish or white 

 charlock, and a common weed throughout Europe, and also 

 adventive in the United States. He bases his opinion on his 

 own experiments which in brief were as follows : The seeds of 

 Raphanus raphanistrum, which has very woody and slender 

 roots, were planted and after five years of care there was 

 developed a type of root which was fleshy, large, and varying 

 in form and color. The roots developed had the flavor of our 

 garden radishes and were edible. In spite of the experiments 

 of Carriere, many botanists believe that white charlock is not 

 the projenitor of the radish. For example, it is known that 

 the garden radish long ago was a common plant in India, 

 China, and Japan. But Raphanus raphanistrum is not 

 found in these countries, and furthermore, the main move- 

 ment of cultivated plants has not been from Europe to Asia, 

 but from the orient to the Occident. The true history of the 

 radish seems to be unknown. 



Closely Related Species. — Raphanus raphanistrum, white charlock, men- 

 tioned above, may be quite easily mistaken for the common radish, especially 



