270 NEW JERSEY AGRICULTURAL COLLEGE. 



a tendency to become lobed (5) is met with usually upon one 

 side that gives rise to a "mitten," so frequently found in the 

 Sassafras. Other leaves may show lobation upon both sides 

 (6), thus producing three divisions of the blade. Furthermore, 

 the separation may continue until four, five (7), and very 

 likely more lobes are produced. The samples of forms shown in 

 the lower portion of Plate XXII are all from the same plant and 

 no extended search was made for a longer series, the point being 

 to show that with plants of the palmate type, there may be many 

 degrees of lobation determined doubtless, in large part, by the 

 number and position of the main veins and the position of the 

 leaf upon the plant, its supply of nutrition, including soil and 

 air conditions. 



In these Ambrosias it is noted that one species, as previously 

 stated, has comparatively constant foliage for the same plant 

 but exhibits a striking variation in the species. Somewhat 

 contrariwise, the second Ragweed has a very wide range of leaf 

 forms upon the same branch. The difference in this regard may 

 be due to the type of leaf where lobation means much to the eye 

 in one and not in the other. 



THE GREEN MILKWEED. 



The Green Milkweed {Acerates viridiflora Eaton) is somewhat 

 common upon the dry knolls in the vicinity of the Experiment 

 Station, and for years has been a subject for casual observation 

 as regards, in particular, the constancy of the leaves upon any 

 single plant and the great variation when the plants as a whole 

 are considered. 



In September last one hundred plants, all bearing maturing 

 pods, were cut close to the ground and at random upon the same 

 morning over an area of near five acres. The following points 

 were tabulated: (i) height and (2) color of plant, (3) number 

 of pairs of leaves, (4) their length, (5) breadth and (6) shape 

 of tip, (7) number and (8) size of pods. 



The following table shows the height of the plants: 



Centimetres. . 22 23 24 25 26 27 28 29 30 31 32 33 34 35 38 37 38 39 40 

 Instances. ... 131122204 4 6244 44524 



Centimetres. . 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 57 60 73 

 Instances. ... 127334541,1 1 2 3 1 3 2 1 1 



There is no one norm around which the heights are grouped, 

 that is, from 30 to 48 cm. the variation is quite within the range 

 of expectation for so few instances. 



