368 



Mr. Halst adheres to bis belief ^' that there must be ver}^ extensive 

 fertilizatioQ of tlie dehiscent species of Yucca by the agencies of bees 

 and other insects." He does not bring forth a single definite fact or 

 observation of actual i:)olli nation to prove or sustain the belief, but rests 

 it on the following grounds : 



1st. That Meehan found that the mere application of pollen to the 

 papillose apex of the stigma is sufficient for fertilization. 



2d. That he (Hulst) has seen honey-bees within the open as well as 

 the partly open flowers, as also other insects, Aphides and Coccinel- 

 lidae being particularly mentioned. 



3d. That not one in ten of the capsules subsequently examined by 

 him showed the larva. 



4th. That he is informed that dehiscent species of Yucca do ripen 

 seeds in Europe. 



Such are the negative arguments upon which rests his belief in the 

 face of all the facts I have put on record. Let us consider the former 

 briefly in their order. 



1st. My good friend Meehan has written much on the fertilization of 

 Yucca — much, too, that has not shown the keenest penetration nor the 

 strictest ascuracy. But, in candidly admitting his errors when shown 

 to be wrong (as he has done to the writer, and, I have reason to believe, 

 to Mr. Hulst, who sought his support in the belief here combated), he 

 has proved himself to be the true naturalist. I am familiar with his 

 exj^eriments, having witnessed the results, and can best express my 

 own opinion by quoting from a letter from the late Dr. G. Englemaun 

 (written January 10, 1881), in which, among other things, he says : 



As to Meehau's operations, I have seeu myself the fiue, large, well-filled pods of 

 Tiicca angustifoUa raised by him by his artificial method. He says he punches an 

 anther into the stigmatic cavity. Whether he or anybody else could distinguish 

 whether the pollen adheres only to the papillose (not stigmatose) apex or gets into 

 the liquor that fills the cavity when the stigma is ready to conceive, is a question (or 

 no question) ! 



Meehan's experiments were made on a species in which, as I have else- 

 where shown, the stigma is shorter and the stigmatic liquor more abun- 

 dant than in Yucca Jilamentosa, and it may be that for these or other 

 reasons it is more easily poUinized by hand or by other means than by 

 Proiiuba. But I have followed up his experiments, and made many 

 others during the past seven years, on filamcntosa and aloifoUa, with 

 results that convince me that application of the pollen to the papillose 

 apices only is not sufficient to insure fructification, at least in those 

 species. My experiments have been made in the afternoon, evening, 

 and morning, with flowers one day, two days, and three days after 

 opening; with pollen from the same flower or from other flowers either 

 on the same or other racemes, by touching the mere apices with anther 

 or brush, and by forcing the pollen by either conveyance into the stig- 

 matic tube. In these experiments, which have not yet been published, 

 and which it is unnecessary to detail here, I have endeavored to guard 



