156 PROCEEDINGS OF THE ACADEMY OF 



as variation. Inheritance struggles to have the plant fertilize itself with its 

 own pollen ; whilst the efforts of variation are towards an intermixture of 

 races or even neighboring individuals, rather than with members of the one 

 brood or family. May it not be possible that at some time in their past his- 

 tory all species of plants have been hermaphrodite ? that DicEcism is a later 

 triumph of variation, its final victory in the struggle with inheritance ? There 

 are some difficulties in the way of such a theory, as there are with most of 

 these theories ; but it seems clear from this case of Epfffiea that cultivation has 

 not eo much to do with changes as it gets credit for, and we may readily be- 

 lieve that, independently of external circumstances, there is a period of youth 

 and a period of old age inform as well as in substance, and that we may there- 

 fore look for a continual creation of new forms by a process of vital develop- 

 ment, just as rationally as for the continued succession of new individuals. 



The discovery of dioecism in Epigwa is interesting from the fact that it is 

 probably the first instance known in true Ericaciea. In the Ericale suborder 

 of Francoacceay abortive stamens are characteristic of the family, and in the 

 Pyrolaciea antlierless filaments have been recorded. 



Monoecism in LUZULA CAMPESTRIS. 

 BY THOMAS MEEHAK. 



The recent discovery, that many plants structurally hermaphrodite are 

 practically monoecious or dioecious, in consequence of the flower being so 

 arranged as to prevent self-impregnation, is so interesting that every additional 

 fact bearing on the subject has a value. 



Luzula campestris, D. C, adds another to the list. The three stigmas are 

 protruded through the apex of the flower bud some days before the sepals open 

 and expose the anthers. In the specimens I marked for observations, six days 

 elapsed before the flower opened, after the pistils had been protruded to be 

 operated on by the pollen of other flowers. This was in a cloudy week, and 

 probably the exact time might vary with the weather. In all cases the stigmas 

 wither away before the flower opens. 



After fertilization the stigmas generally twist around one another, and after 

 the anthers have shed their pollen they twist in the same way, withering up 

 in a very short time. An interesting fact in Luzula is the slight adhesion at 

 the articulation of the subpedicels with the main flower stalk, — the gentlest 

 force being sufficient to draw thera out of their sheaths. It is perhaps owing 

 to this weakness that the pedicels are often drooping when in fruit. 



June 2d, 1868. 

 Mr. Vaux, Vice-President, in the Chair. 

 Twenty-five members present. 



The following papers were presented for publication : 



" Description of seven new species of Unio from North Carolina." 

 By Isaac Lea. 



" Descriptions of two new species of Unionidse from Equador." 

 By Isaac Lea. 



" New Unionidse, Melanidse, &c., chiefly of the United States." 

 By Isaac Lea. 



" On Agaphelus, a genus of toothless Cetacea." By Edw. D. Cope. 



Dr. Leidy called attention to some specimens of Sombrero Guano 

 containing about 90 per cent, of phosphate of lime. This substance 



[June, 



