clxxvi PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



Scientific Committee, October IB, 1903. 

 Dr. M. T. Masters, F.R.S., in the Chair, and nine members present. 



Male Figs. — Dr. Masters observed that several instances of Figs which 

 had failed to ripen had been sent to him. They were remarkable for con- 

 taining entirely male flowers ; ordinary Figs being entirely female, but 

 ripening without fertilisation, except in the case of the Smyrna Figs, 

 which require " caprification." 



Potato Disease. — Dr. Cooke, V.M.H., replied to inquiries as to the 

 transmission of the mycelium from the leaves down the stem being the 

 only means of reaching the tuber : 



"Attention has been called to the Potato disease, and the transmission 

 of the mycelium from the leaves down the stem to the tubers, the question 

 being raised whether this is the only way in which the disease reaches the 

 tubers. It has been suggested that according to this theory the disease 

 would first appear in the tubers at the point where it is connected 

 with the stem by means of the threadlike offshoots, and it is stated that 

 as a result of examination it was found that the tubers were diseased only 

 on the end opposite to that by which they were connected with the stem, 

 and in some cases it only penetrated the outer skin. This raises the 

 pertinent inquiry whether the tuber may not contract disease from active 

 spores in the soil, without connection with the surface portion of the 

 plant. 



" To this I may add that I have seen similar instances, and that it is 

 my own individual opinion that the disease may be communicated direct 

 to the tubers while young and with a delicate skin or when bruised 

 or wounded, by contact with active conidia or zoospores washed down 

 from the surface of the soil, and that the mode in which some tubers are 

 attacked can only be explained by this hypothesis." 



Clematis Parasite. — Dr. Cooke also reported on a new disease : 

 *• Specimens sent by Mr. Chittenden from Chelmsford of a new parasitic 

 mould on the sepals of one of the forms of Clematis Jackmanni, deserves 

 to be reported upon, as it may occur again in other places. It has 

 been called by Mr. Chittenden Ovularia clematidis, and I agree with his 

 determination. (Fig. 176.) 



" The spots are epiphyllous, white, conspicuous, circular or sub- 

 circular, 2-4 or 5 cm. diameter. Mycelium colourless, branched, 

 creeping. Fertile hypha? erect simple, 40-60 x hi- or triseptate. 

 Conidia hyaline, solitary, continuous, elliptically cylindrical, rounded at 

 the ends, 28-42 x 14-16//, smooth. 



" At present no experiments have been made to check this parasite, 

 and it is quite uncertain whether it will establish itself, but, if it should 

 do so, it would be well to try powdered sulphur at first, and, if this is 

 not successful, to fall back upon Bordeaux mixture." 



Vegetable Monstrosities. — Mr. Worsdell exhibited a spray of Pelar- 

 gonium with foliaceous bracts at the base of the umbel, and a fasciated 

 peduncle ; also flower-heads of Scabiosa atropurjmrea with proliferous 

 axis. Mr. Wilks observed that this is particularly common on plants 

 grown from German seed. 



