140 HARSHBERGER— STUDY OF THE CLOVERS. 



Statistical Study of Red Clover Variations. — The usual state- 

 ments in the manuals of botany about the size and other character- 

 istics of the organs of the species included in the manual are not 

 based on accurate measurements for statistical purposes. In order 

 to provide such data for the common species of Trifolium, measure- 

 ments were made of one hundred red clover plants as a beginning. 



The length of the petioles above the stipules of one hundred 

 leaves varied from 271 mm., the longest, to 38 mm., the shortest. 

 The length of the middle leaflet of the three leaflets varied from 

 44 mm., the longest, to 15 mm., the shortest. The widest middle 

 leaflet was 29 mm., and the narrowest 12 mm. Similarly measure- 

 ments were made of the right and left leaflets of the trio with the 

 following results : 



Longest Left Leaflet 42 mm. 



Shortest Left Leaflet 15 mm. 



Widest Left Leaflet 26 mm. 



Narrowest Left Leaflet 12 mm. 



Longest Right Leaflet 43 mm. 



Shortest Right Leaflet 13 mm. 



Widest Right Leaflet 29 mm. 



Narrowest Right Leaflet 10 mm. 



Out of 100 leaves, 78 had leaflets with retuse apices and 22 had 

 leaflets with obtuse apices. The three leaflets of our common field 

 red clover are marked usually (89 out of 100) with U-shape, or 

 V-shaped, whitish blotches, as if one had placed a dab of white paint 

 on the leaflets with the fleshy part of the thumb. In some cases these 

 markings are pale, in other cases prominent. Eleven plants in one 

 hundred were found entirely without the thumb-mark spots. Some- 

 times a red clover plant has been found in which the white color runs 

 along the veins in streaks toward the midribs of the leaflets. This 

 arrangement of color may be due the action of an enzyme in pro- 

 ducing the variegation, or to the presence of air beneath the surface 

 in the V-shaped area. A little boy, Roger M. Hinckley, aged 11, 

 writes to St. Nicholas (1909) from Greenfield, Mass., about a crinkly- 

 leaved white clover with leaflets panduriform. A figure is given of 

 this variation, probably induced by disease. 



