THE AMERICAN BOTANIST 27 



illustrate this condition. It is true that there are a few woody 

 legumes in temperate regions, but they are greatly outnumbered 

 by the herbaceous species. In the tropics the reverse is true; 

 herbaceous species are rare but there are an immense number 

 of woody forms. When we turn to the past geological ages 

 when the climate was warmer, we find the bulk of the vege- 

 tation arborescent in nature. The evidence seems conclusive, 

 therefore, that the herbaceous type is a response to cooler 

 conditions and is much later in origin. The death of parts 

 above ground, or, in the case of the annuals, the death of all 

 the plant but the seeds, seems to be an adaptation for preserv- 

 ing the race. Plants which could endure the annual loss of the 

 parts above ground would of course be able to push farther 

 into colder and less hospitable regions. 



Sir Walter Raleigh's Potatoes. — The introduction of 

 the potato into Europe is often ascribed to the efforts of Sir 

 Walter Raleigh, but it is possible that historical writers may 

 have been misled by mention of potato-like vegetables in the 

 early accounts. Certainly the plant mentioned by Raleigh's 

 servant, Thomas Herriot, in his account of Virginia was not 

 our familiar tuber, for he says of it, "Openawk is a kind of 

 roots of round form some of the bigness of walnuts, some far 

 greater, which are found in moist or marsh ground, growing 

 many together, one by another in ropes as though they were 

 fastened with a string. Being boiled or sodden, they are very 

 good meat." This cannot be the potato in common use for the 

 potato does not grow in marshy ground and is not produced 

 in "ropes." The description points unmistakably to the 

 groundnut or wild bean (Apios tuberosa) and bears interesting 

 testimony to the fact that in 1588 the Indians used the ground- 

 nut for food. It is quite possible that the extensive patches 

 of this plant that occur on the borders of swamps and low 

 lands were not altogether the results of the unaided distribution 

 of the plant, but that the Indians may have had a hand in it. 



