WEDDELUS MONOGRAPH OF URTICACE.E. 87 



coming very hard and warty, unfit for the table and unsafe 

 to give to cattle." — (" Fl. Cestrica," ed. 2, p. 555.) 



Now that this is not the effect of hybridation is clear from 

 the fact that the result appears in the fruit of the season, 

 not in that of the next year, namely, in a generation origi- 

 nated by the crossing. A clue is perhaps furnished by Nau- 

 din's observations, that the ovary is apt to set and even de- 

 velop into a fruit in consequence of the application of the 

 pollen of another species, although, as the result proves, none 

 of the ovules are fertilized. ^ And he hazards the conjecture 

 that the pollen may exert a specific influence first upon the 

 ovary, inciting its farther development, and then upon the 

 ovules. To test this conjecture he was to examine the action, 

 if any there be, of the pollen of Cucurbita upon the ovary of 

 melons. The past summer — which has been as unusually 

 warm in western Europe as it has been cool in this country 

 — must have favored such researches in Paris ; and we may 

 expect soon to hear of the result. Improbable as such an 

 influence seems to be, it is hardly more so than the now 

 authenticated fact that the graft of a variegated variety of a 

 shrub or tree will slowly infect the stock, so that the varie- 

 gation will at length break out in the foliage of the natural 

 branches ; — an old observation, which, according to the Gard- 

 ner's Chronicle, has recently been verified in several instances. 



WEDDELL'S MONOGRAPH OF URTICACE^. 



Dr. Weddell's preliminary studies upon the proper Urti- 

 cacece were published a few years ago in the " Annales des 

 Sciences Naturelles." Since then, botanists, aware from this 

 and his other works that the subject was in most able hands, 

 have been anxiously waiting for his full monograph. This, 

 we understand, is now completed, although the last fasciculus 

 has not yet reached this country. The greater part is before 

 us, and an admirable monograph ^ it is, worthy of a place in 



1 Monographic de la Famille des Urticees. Par H. A. Weddell {Archives 

 du Museum, vs.., livr. 1^), 1856-57. (American Journal of Science and 

 Arts, 2 ser., xxv. 109.) 



