OALLESIO'S TREATISE 0^~ THE CITRUS FAMILY. 



11 



are obtained the fol- 



From these experiment: 

 lowing conclusions: 



Consequence I. The seed perpetuate., the bpe 

 cics and is tho source of varieties. It produces | m ind! 



sterility, ami illume modifications ul leaf known 

 as curled or streaked. 



more' frequently varieties interior to the mother 

 plant ; sometimes, however, those superior to it. 

 It never departs from the species unless the fecun- 

 dation of another species gives it tho germ of a 

 hybrid. (Exp. 1 and III.) This occurs equally 

 in the seed of the seedling and that of the grafted 

 tree. The trees which come from them repro- 

 duce the same species which gave the seed, aside 

 from the modification of varieties noticed above. 

 (Exp. IV.) 



Consequence 11. The seeds of monsters, when 

 they arc found, produce only ordinary fruit, 

 which indicates that this extraordinary fruit is 

 only a variety, and that the variety returns to 

 the type in the seed. (Exp. II.) 



Consequence III. The seeds of the ^weet orange 

 produce only sweet orange trees ; sour orange 

 seeds produce only sour orange trees. These 

 two orange trees arc preserved and perpetuated 

 by the seed, and are, therefore, distinct species. 



A crowd of reflections were presented to my 

 It is recognized, I reasoned, that two dif- 



ferent principles must co-operate for the repro- 

 duction of all organized beings. We know that 

 when these principles belong to different specieo 

 monstrosities result, such as rnules among ani- 

 mals, and among vegetables tho mixed plants 

 known under the name of hybrids. 



Why may not this principle, which effects so 

 many phenomena, be the cause of monsters and 

 varieties V These, it is true, do not prove the 

 mixture, lor they arc produced even from the 

 seed of isolated trees ; but is it necessary that 

 the principles of two different species unite in 

 fecundation in order to change the physiognomy 

 of the product ? Cannot this be as well accom- 

 plished by different properties of the two agents 

 in the same species, and perhaps also by a differ- 

 ence in the force of their action, or by a defect 

 in tho uimlofiry in their principles? Is it not 

 from the different proportion of these two agents 

 of organic reproduction, that results this mar- 



peculiar physiognomy? There is no fruit in the 

 same plant even which is exactly like any other. 



The ordinary peach never produces the cling- , } ^ . ^ distinguisbiug all anima l 8 by a 



*tone, nor the cling-stonc the ordinary peach, | ..._,._ _,._/? o r ru ,_ : ,.-. .;,.,. 



and hence they are two distinct species, and can | 

 not degenerate from the one to the other. The 

 same is true of the sweet and bitter almond. \ 

 (Exp. I and IV.) 



Consequence IV. The seeds of lemons grow- \ 

 ing in a garden where lemon and citron trees | 

 rew together, produced poncires. This fruit is, 



therefore, probably a hybrid of the citron, the 

 absence of seeds showing that it is due to a for- 

 eign fecundation. (Exp. III.) 



AIIT. VI. The theory of vegetable 



My experiences as a whole sufficiently sub- 

 stantiated the most of the phenomena presented 

 by the multiplication from seed. They deter- 

 mined the origin of varieties in plants. But it 

 remained still to know the secret causes of these 

 results why nature departed in some cases from 

 the system generally followed in reproduction. 

 Every seed in nature is only the germ which 

 is to renew the individual which produced it ; 

 but some vegetables we have seen depart from 

 this system. 



What is the cause of these exceptions ? I ob- 

 served that these phenomena took place from pref- 

 erence in the seeds taken from plantations where 

 there was a mixture of species or varieties ; that 

 lemons gathered in the garden where there were 

 citrons gave more varieties than those from trees 

 standing alone ; that the seed of the black cabbage 

 which had flowered in the midst of many cabbages 

 of different varieties, produced frequently cab- 

 bage remarkably well headed, much sought for its j 



Might not the inequality which exists among 

 the fruits of a single tree, as we observe it among 

 the children of the same father, exist still more 

 pronounced between tho fruits of two different 

 plants, although of the same species ? Should not 

 the pollen of the flower of one peach tree have a 

 family likeness which would make it different 

 from, that of the flower of another peach tree, 

 and if these two peach trees, modified in their 

 conception by fecundation, were already marked 

 by those differences which constitute varieties, 

 would not the reunion of their flowers produce 

 a new combination which would constitute a 

 variety still more irregular V Finally, what might 

 not the difference in the proportions and the 

 mixture of several pollens produce ? Would iiol 

 a forced fecundation act upon the ovary in an 

 extraordinary manner, and changing tho natural 

 relations of the principles, form heterogeneous 

 combinations incapable of bearing sexual organs ? 



All these queries were presented to my mind 

 in a manner so favorable and seductive that I 

 made no delay in preparing experiments to 

 throw light upon them. Their results have been 

 so satisfactory that I have been able to draw 

 therefrom a theory which has served as the basis 

 of my classification of orange trees. I shall give 

 an explanation of them. 



AKT. \LLfcrpci'intcnts in artificial fecundation,. 

 Experiment V. I chose a number of plants of 



delicacy and whiteness ; that the seed of the ' the Asiatic, ranunculus, of simple flower, and of 



crowfoot of several colors, which I cultivated in 

 quantity in plots of my garden, gave very often 

 double flowers, while this did not happen with 

 the seeds of the same flowers which I had culti- 

 vated in vases, each by itself, before the estab- 

 lishment of my flower garden. 



All these observations presented a certain anal- 

 ogy between the hybrids and the monsters, and 

 i suspected that the influence of the pollen which 

 rfl'pptod Ihe mix'lurp in hybrids might also ciui^c 



different colors. I put each one in a vase, and 

 placed them in as many different windows, sep- 

 arated from each other. I fecundated the flowers 

 of ouc-hnlf these slants with the pollen of each 

 other, but left the other half undisturbed. The 

 following results were obtained : The seeds of 

 the flowers fecundated a.s albrcstated produced 

 roots of which some gave double flowers, others 



semi-double, and the greater part only 

 Hewers. Thr plants not fecimanted jrnvo only 



