April, 1921] Reversal of the Sexual State 191 



Fig. 9 represents a carpellate flower with its edge extending 

 into a staminate area. This gynecium is nearly normal but it 

 has an anther growing out of the side near the top. Fig. 10 rep- 

 resents a similar gynecium with two anthers growing out of 

 the side toward the staminate patch. Fig. 11 is a normal 

 gynecium with a large anther at one side near the top. In Fig. 

 12, a nearly normal stamen is growing out from near the base 

 of the gynecium. Fig. 13 represents a gynecium exactly on the 

 transition line. The ovulary is quite normally shaped. On 

 the side toward the carpellate area there is a normal V-shaped 

 stigmatic surface. In the middle are present a number of 

 abnormal outgrowths, one with a small stigmatic tip. On 

 the side next to the staminate area is one stamen with a double 

 anther and two separate anthers, one of them very close to the 

 stigma. Fig. 14 represents a reduced flower from the transition 

 zone with three anthers growing from the side of the ovulary. 

 Fig. 15 represents a flower so situated that the transition line 

 passes through its center. On the one side is an imperfect 

 ovulary with a two-forked stigma, on the other side of a central 

 depression are two anthers. Fig. 16 represents a small area 

 of flowers carpellate on one side and staminate on the other. 

 On the transition zone there is an imperfect ovulary represent- 

 ing about one-third of a normal structure while two-thirds is 

 transformed into a staminate tissue bearing two anthers. 

 Sometimes the transition zone appears to contain a rather 

 broad strip of neutral tissue. Such a condition is shown in 

 Fig. 17. One ovulary, somewhat to the carpellate side of the 

 zone, is considerably reduced in size. The next one is very 

 rudimentary while the third has developed into a long-horn-like 

 vegetative structure similar to the vegetative projections fre- 

 quently developed on the neutral part of the spadix above the 

 carpellate part. 



Myriophyllum heterophyllum Mx. Variant-leaf Water-Milfoil. 



The water-milfoil has a spike which passes rather gradually 

 from the female state below to the male state above. The 

 carpellate flowers have large stigmas and minute petals and 

 stamen vestiges. The staminate flowers above have small, 

 vestigial stigmas, large, normal stamens, and large petals. The 

 small and large petals are sex-limited characters. The carpellate 

 flowers also have somewhat larger sepals than the staminate 



