Chap. III. MITCHELLA REPKNS. 125 



what is much more important, they were in a rudimentary 

 condition in the two flowers examined by me, and did not 

 contain a single grain of pollen. In the short-styled form, 

 the divided stigma, which as we have seen is much short- 

 ened, is thicker and more fleshy than the stigma of the long- 

 styled, and is covered with small irregular projections, 

 formed of rather large cells. It had the appearance of hav- 

 ing suffered from hypertrophy, and is probably incapable 

 of fertilisation. If this be so the plant is dioecious, and, 

 judging from the two species previously described, it proba- 

 bly was once heterostyled, and has since been rendered 

 dioecious by the pistil in the one form, and the stamens in 

 the other having become functionless and reduced in size. 

 It is, however, possible that the flowers may be in the same 

 state as those of the common thyme and of several other 

 Labiatse, in which females and hermaphrodites regularly 

 coexist. Fritz Miiller, who thought that the present plant 

 was heterostyled, as I did at first, informs me that he found 

 bushes in several places growing quite isolated, and that 

 these were completely sterile; whilst two plants growing 

 close together were covered with fruit. This fact agrees 

 better with the belief that the species is dioecious than that 

 it consists of hermaphrodites and females; for if any one 

 of the isolated plants had been an hermaphrodite, it would 

 probably have produced some fruit. 



KUBIACEJE. 



This great natural family contains a much larger 

 number of heterostyled genera than any other one as 

 yet known. 



Mitchella repens. — Professor Asa Gray sent me sev- 

 eral living plants collected when out of flower, and near- 

 ly half of these proved long-styled, and the other half 

 short-styled. The white flowers, which are fragrant 

 and which secrete plenty of nectar, always grow in 

 pairs with their ovaries united, so that the two together 

 produce "a berry-like double drupe/'* In my first 



* A. Gray, ■ Manual of the Bot. of the N. United States, ' 1856, p. 172, 



