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THE GARDENERS MONTHLY 



[OCTOBEE, 



threads, which force their way in all directions 

 between the cells of the leaf, thrusting their 

 suckers into the cells to rob them of their con- 

 tents. When the time for fruiting comes, some 

 of these threads push through thestomata of the 

 leaf-branch considerably, in a definite and pecu- 

 liar manner, bearing the conidial spores on their 

 tips. 



Under the head of the germination of these 

 asexual bodies. Dr. Farlow has several interest- 

 ing experiments. They germinate equally well 

 in the dark as in the light. Those sown in the 

 morning germinate more quickly and abun- 

 dantly than those sown in the afternoon. It 

 was not possible to keep the conidia which 

 were produced in the night until the afternoon, as 

 they generally fell from their attachments in the 

 morning, and began to germinate. In all cases 

 the germination took place with surprising regu- 

 larity. At the end of an hour the conidia were 

 slightly swollen, and their contents had begun 

 to segment, each segment having a light-colored 

 nucleus. At the expiration of an hour and a 

 quarter, the segments had resolved themselves 

 into a number of oval bodies, which collected at 

 the distal end of the conidia, and which, before 

 long, succeeded in rupturing the cell wall and 

 making their escape from the mother cell. They 

 passed out rather slowly, usually one at a time, 

 and paused for a moment in front of the open- 

 ing, where they remained as if not yet quite free 

 from one another. In a short time each seg- 

 ment began to extricate itself from the common 

 mass, moved more and more actively, and finally 

 darted off with great rapidity, a full-fledged 

 zoospore, furnished with two cilia. The average 

 number of these rapidly moving spores is from 

 six to eight. Their movement gradually grows 

 slower, and in fifteen to twenty minutes come 

 to rest. Soon an outgrowth proceeds from one 

 side, and rapidly develops into a new plant. 



The oospores, which are the result of sexual 

 action, are found in autumn within the tissue of 

 the shrivelled leaves as spherical, thick-walled 

 bodies. They escape by the breaking up of the 

 dry leaf, or through the decay of the surround- 

 ing tissue. 



The fungus under consideration is common 

 on Vitis aestivalis, — Michx., V. labrusca L., and 

 their cultivated varieties; V. cordifolia, — Michx. ,^ 

 V. vulpinata, and nearly all varieties of culti- 

 vated grapes. The statement is often made that 

 it does not grow on V. vinifcra. By carefully 

 conducted experiments in the laboratory. Dr. 



Farlow found this mildew could be made to 

 grow on the leaves of this European species, and 

 with the usual luxuriance. 



It is quite gratifying to know that so common 

 a disease as this one upon the grape does no 

 real damage, but on the contrary is beneficial to 

 the grape crop. It makes its appearance late 

 in the season, when the large leaves have fin- 

 ished their work. By shrivelling up the leaves, 

 the Peronospora enables the sun to reach the 

 grapes without loss to the vines, as is shown by 

 the fact that the vines continue to live on from 

 year to year without apparent injury. 



In Europe, where the " winters are warmer, 

 the springs earlier, and the summers much 

 moister than here, it is quite possible that the 

 advent of the Peronospora, by reason of the 

 greater warmth and moisture, would be some 

 weeks earlier than here, before the vine had 

 attained its growth, and at a time when the 

 leaves are needed for the work of absorption and 

 assimilation." Should this be the case, the dis- 

 ease which with us gives little cause for alarm, 

 might prove very disastrous in the vast vine- 

 yards of Europe. 



THE SOUR AND SWEET APPLE. 



BY W. S. W., PHILADELPHIA. 



I have just read in the newspapers your speech 

 at Buflflilo on " Grafted Hybrids." 



Some thirty years ago there stood in my 

 uncle's orchard in Stafford, Conn., a small apple 

 tree which bore fruit, one side of which was 

 sweet and the other side sour. I was told that 

 this result was brought about by inoculating a 

 young tree with a half of two buds taken respec- 

 tively from sweet and sour apple trees, and 

 firmly joined together before the inoculation. I 

 do not know what the varieties were that were 

 joined together for the inoculation, but the hy- 

 brid product was of no account except as a 

 curiosity. Indeed, so far as I remember, the 

 fruit was apt to be imperfect in form, and not 

 always possessing the characteristic of " one side 

 sweet and the other side sour." A few years 

 since I visited the place, hoping to procure a 

 specimen apple for a scientific friend, but found 

 that the tree had gone to decay. I have, there- 

 fore, to rely upon the impressions of my boy- 

 hood, and do not know that I could substantiate 

 these statements by any one now living. Still I 



