82 



APPLIED BIOLOGY 



various colors; (3) the leaves may differ in shape, size, and 

 color; (4) the pods may be rounded or flattened, short or 

 very long (in one variety two to three feet), green or yellow 

 (so-called "wax beans"), with "strings" ( 77) or almost 

 " stringless," and with many flavors; (5) some bean plants 

 form edible pods in six or seven weeks after planting (the 

 early and extra-early varieties), while others take a longer 

 time (lima beans are often killed by frost before the seeds 



are full size). 

 These are a few 

 of the variations 

 of beans which 

 interest garden- 

 ers, because all 

 these are quali- 

 ties sometimes 

 desired. Look 

 over the descrip- 

 tions of beans in 

 a seed-catalogue, 

 and note the 

 points empha- 

 sized in the de- 

 scriptions of va- 

 rieties offered for 

 sale. 



79. Structure of 

 a Bean. (L) Use 

 any large beans 

 (limas, "yellow six- 

 golden-eyed wax" are excellent) ; 

 some dry, and some which have been soaked in water over night. 

 Examine the surface markings. Locate the scar or hilnm and 

 the micropyle, which were described in the preceding lesson on the 

 pod. The translucent elevation seen in green beans near the hilum 

 and opposite the micropyle is colored in dry beans of many varieties 



FIG. 33. Bean seed and seedlings. 

 e, epicotyl; h, hypocotyl; r, roots, 

 son.) 



weeks," "scarlet runner," and 



c, cotyledons; 

 (From Atkin- 



