t02 THE PLANT WORLD. 



at its mouth, is finely and irregularly toothed. The perichaetial bracts 

 are found below the perianth and pass gradually into normal leaves so 

 that it is impossible to draw a rigid line of distinction between them. 

 The bracts of the pair next below the perianth are the most character- 

 istic ; they are almost transversely inserted and are appressed to the 

 base of the perianth. Like ordinary leaves, they are normally four- 

 toothed, but the teeth and their sinuses tend to be more acute than is 

 usual and their margins frequently bear one or more slender teeth or 

 appendages. The underleaf corresponding to these bracts is much 

 larger than the normal underleaves and is known as a "bracteole." 

 It is irregularly divided into sharp segments and is either free or con- 

 nate with one of the bracts at the very base. It was said above that 

 the formation of archegonia terminated the growth of the stem ; very 

 often, however, one or two branches, known as "innovations," are 

 developed from its lower surface close to the perianth. These lengthen, 

 apparently forming an elongation of the stem, and, if they grow luxu- 

 riantly, sometimes force the perianth to one side, so that it appears 

 almost as a lateral organ. 



Most of the points brought forward in the above description are 

 illustrated by the accompanying figures. Specimens for study will 

 gladly be sent by the writer to any one who may desire them. 



Yale University. 



PARTHENOGENESIS IN COMMON PLANTS. 

 By Edward L. Greene, LL. D. 



LAST spring, while occupied in an attempt to segregate certain 

 species of Cudweed which had been confused under the name 

 of Antennaria plantaginifolia, I seemed to discover certain very 

 curious facts in relation to the propagation of the species. All 

 the individuals of all the species of Antennaria appear to be strictly 

 unisexual ; and, after having explored acre after acre of the true Plan- 

 tain-leaved Cudweed, and in different localities, in search of male 

 plants, I gave up without having found a single specimen of that sex. 

 Yet, the untold thousands of female plants yield seed in abundance, 

 and the species is propagated freely by such seed. 



In my earliest segregate from that species, A. neglecta, the male 

 plants, though common enough, are in flower about two weeks in ad- 

 vance of the females, even when growing together; so that, by the time 

 the stigmas are developed in the female plants, the flowers of the male 

 are dry and dead, their pollen gone. Moreover, in both these com- 

 mon plants, one fails to find a trace of pollen from any source, or of any 



