1892.] NATURAL SCIENCES OF PHILADELPHIA. 167 



in almost every respect, .some in form of leaf or flower, others in 

 manner of growth or general habit. One very vigorous grower, 

 with a loose rambling habit, was compared with one of compact 

 formal growth. The leaves and general characteristics of each 

 were precisely the same ; but in one the internodes were eight 

 inches, while in the compact form they were but four. The whole 

 diflference in appearance Avas dependent on this single circumstance. 



On the Sexes of the Holly. 



In Martyn's edition of Miller's " Gardener's Dictionary," published 

 in 1807, much stress is laid on the fact that the English holly. Ilex 

 Aquijolmm, is dioecious. Philip Miller say it was discovered first by 

 his father. It was considered a very important discovery as removing 

 Ilex from the class Tetrandria, where Linnjeus placed it, and giving 

 it place in Polygaviia dimcia. In those days botanical facts of this 

 character had bearing on few other questions than that of classifica- 

 tion. It is not surprising, therefore, that authors since Martyn's 

 time have hardly thought the matter worthy of any consideration. 

 The most cx'itical of all English botanists. Dr. Arnold Bromfield, 

 in his "Flora Vectensis," giving nearly two pages of close print to a 

 minute description of every character, passes over the question of 

 sex by observing ; " the earlier flowers are said to be generally 

 imperfect, and such as are 4-cleft to generally want the germen 

 which accounts for the small quantity of berries produced by some 

 trees which flower abundantly." 



In these days when the laws which influence the production of 

 sexes in flowers, and the various questions arising from dimorphism 

 and the relation of insects to fertilization have become matters of 

 paramount importance, the actual condition of the sexual character 

 in the holly is a matter of considerable interest, deserving much 

 more critical attention than has been given it. 



The description given by English authorities fits exactly the 

 characters of the male flowers of Ilex opaca. I venture, therefore, 

 to express an opinion that the Hex Aqulfolium is dioecious like its 

 American relative. I am inclined to believe, however, that the 

 dicecisra of closely related species is much more pronounced in the 

 American than in European forms. This would have an important 

 bearing on evolutionary studies. It would be worth while for 

 observers in the old world to note whether any separate plant of 

 Ilex Aejuifolium has truly hermaphrodite flowers, or even perfect 



