1877.] 



AND HORTICULTURIST. 



117 



botanists, they might have seen further. To 

 make our meaning plain, we may say, " a knife 

 prunes the tree," but it is no more true than 

 that frost ripens Persimmons. There is a hand, 

 if not always a mind, behind the knife, and 

 other things maybe made to do the work as 

 well as the knife. And so, frost is the instrument 

 in some cases. The real power is chemical 

 change, and this can be brought about by other 

 instruments, as well as by frost. 



We know so little from our own experience of 

 the Japan Persimmon, or the Te.xan Persimmon, 

 that we should be glad to hear from correspond- 

 ents who may have had more. It has fruited, 

 we think, in California.— Ed. G. M.] 



ON SELF-FERTILIZATION AND CROSS-FER- 

 TILIZAriON OF FLOWERS.* 



BY THOMAS MEEHAN, GERMANTOWN, PHILA. 



The following paper was read at the Buffalo 

 meeting of the American .dssocia^wn for the Ad- 

 vancement of Science, in August 1876. Other pa- 

 pers by the author on the same subject, have 

 appeared in the Proceedings of the Association. 

 This will not appear with the others. Being on 

 a popular subject, it was sought for by some of 

 the papers, and appeared in one ; but after such 

 appearance, the Publication Committee is not ex- 

 pected by the association to issne it in their 

 volume. Believing, however, that scarcely any 

 of the members of the association for whom the 

 Proceedings are issued, will have seen it where 

 printed, and that it may possibly interest some 

 of them, particularly at this time, the author 

 gives it in this form : — 



" At our last meeting I enquired whether in- 

 sects are any material aid to plants in fertiliza- 

 tion. After another year of observation I desire 

 to answer my own question in the negative. In- 

 sects, sometimes fertilize flowers, and cross-fer- 

 tilize them ; but I believe these cases are less 

 frequent than they are supposed to be ; and that 

 when they do occur, they have no bearing on 

 the general welfare of the race. In other words, 

 such fertilization is of no material aid to plants 

 in the progress of the species. I may repeat the 

 argument of those who differ from me: All 

 plants with brilliant colors, with fragrance, or 

 with honeyed secretions, have these attractions 

 for the purpose of enticing insects, which un- 



» Prof. C V. Riley, after the readinc, expressed doubts as to 

 whether Yiicea would fertilize by its own pollen in this way and 

 without insect aid, and a^ked leave to cut open the capsules, 

 confident, he said, of findinf: larvae. He cut them open in the 

 presence wf the audience, but fuuud none. 



consciously bring pollen at the same time, and 

 thus cross-fertilize the flower. The proof of this 

 is thought to be chiefly in the fact that many 

 plants do not perfect their stamens and pistils 

 at the same time ; are placed in relative posi- 

 tions which seem difficult or even impossible 

 that they should have any influence on each 

 other; or in some other way present apparent 

 obstacles to sexual union. From this it is as- 

 sumed, and not from any actual experiment that 

 I am aware of, that plants abhor close breeding. 

 That plants abhor close breeding, is an idea bor- 

 rowed from a supposed experience in the higher 

 animals. But the comparison is not fair. In 

 the higher animals the idea of sex is essential to 

 the perpetuity of existence; but it is not so in 

 plants. They reproduce themselves by bulbs, 

 tubers, suckers, offsets, buds, and in the lowest 

 organisms by simple cell division. Propagation, 

 as an idea, is entirely independent of sex in 

 plants. True, many of our forest trees have none 

 of these accessories; even the skilful horticultu- 

 rist can scarcely graft some of them ; and then 

 there are annuals which depend wholly on 

 seeds— a product of the sexes— for perpetual 

 existence. But there is not one that I know of 

 that a horticulturist would say, could not be re- 

 produced indefinitely without the aid of seeds. 

 The Red Dutch Currant is an individual plant 

 which has been reproduced by cuttings from 

 long anterior to modern history ; and I believe 

 the Canada Thistle, Couch Grass, Horse Radish, 

 and numerous other plants could be continued 

 for countless ages by their running roots alone. 

 Now this is a closer kind of breeding than any- 

 thing that could come through the operation of 

 separate sexes, and with which no analogy can 

 be drawn from any experience in the higher 

 forms of animal life. We can see that seeds in 

 plants favor the distribution of species, and en- 

 able them to maintain existence for a longer 

 period than mere plants could. Sex in plants 

 may be a factor in the evolution of form ; but 

 those who have kept pace with botanical know- 

 ledge, and are familiar with what is known as 

 bud variation, will not lay much stress on the 

 absolute necessity of sex to this end, in vegetable 

 nature. I believe I am safe in saying that there 

 is nothing whatever known to prove that there 

 is any physiological benefit to plant races by the 

 establishment of the sexes. Some have thought 

 that the varieties of apples wear out in time ; 

 but even this is being argued on both sides by 

 the most distinguished horticulturists; and I 



