238 REPORT OF STATE BOARD OF HORTICULTURE. 



In many instances it has been observed that some trees will produce at 

 times an abundance of flowers of one sex, and few or none of the other sex. 

 Trees — as the walnut — that mature their pollen before the female flowers on 

 the same tree are ready for fertilization, are called by hotanists proterandroufi: 

 while others, called proteroyynous, have their stigmas mature before the 

 pollen is ready. The purpose of this curious functional difference obviously 

 is in favor of cross-fertilization, by pollen, of flowers borne bj' other trees of 

 the same si^ecies. 



According- to the Gardeners' Chronkic. in 1888, reports became current of 

 trees in portions of the walnut sections of France bearing a full crop, but the 

 nuts failed to harden, the husks, when about half grown, withering up, and 

 few good nuts were found. The kernels which were formed, were soft and 

 insipid. Reports made throughout were that "while there were plenty of 

 nuts, there was nothing in them," and after assigning different reasons for 

 this failure, conclude "probably from imperfect fertilization of the flowers." 

 Many other similar instances are reported as occurring in different groves. 



*"It is a common occurrence for the walnut to be deficient in producing 

 either the male or female blossoms, which it bears, both of which are essen- 

 tial to its producing and ripening nuts. I have a tree, now about twenty 

 years old, which began a few years ago to show blossoms, but those merely 

 female, without one male catkin appearing on the tree, and the consequence 

 has been that after the flowers faded, the fruit regularly dropped oft'. This 

 season, there being a considerable show of female blossoms but no male ones, 

 J thought of trying the plan followed by gardeners in the case of mellons and 

 other fruits where fertilization is not freely effected by nature, and having 

 seen abundance of male catkins on a tree at a friend's, I asked him to send 

 me some, and he accordingly sent me a small paper-bag full, which I dusted 

 and threw over such of the female blossoms as were within my reach. The 

 consequence has been that I now have about a dozen fine nuts, swelling out 

 regularly, with every appearance of coming in due time into maturity. All 

 the embryo fruit not fertilized have fallen off as usual. I am pleased with 

 the result of my experiment, and mean, should my tree still prove deficient 

 in male blossoms, with the assistance of my friend's, to supply its wants, and, 

 by taking a little more trouble, I have no doubt I shall be able to render 

 every female blossom fruitful." 



As showing this curious functional diff'erence in our own state, a few facts 

 are cited. A nurseryman at Ventura observed a large seedling walnut tree, 

 which, from its luxuriant growth and symmetrical form, he believed would 

 be a variety worthy of cultivation. Accordingly, in the spring of 1886, he 

 planted forty pounds of nuts gathered from that tree. When the seedlings 

 bore, none of them produced nuts of any commercial value. This, of course, 

 proved to be a sad disappointment to him, and, after waiting ten years for a 

 crop, he dug up most of them. Some of the trees had become of large dimen- 

 sions and had long, spreading branches, and were always quite full of nuts, 

 but without kernels — all hull and shell. This functional diff'erence was 

 investigated ; the trees were found to produce an abundance of flowers of the 

 same sex, but few or none of the other, through which imperfect fertilization 

 of the flowers, the kernels in the nuts did not form — they were wanting. It 



* Gardeners^ Clironicle London, 1847, p. 54L 



