SCIENTIFIC COMMITTEE, MAY 8. 



xxix. 



Scientific Committee, May 3, 1892. 



Dr. M. T. Masters in the Chair, and five members present. 



Narcissus Basal Mot. — Specimens of the variety Troilus 

 were sent by the Kev. W. Dod, with the following communi- 

 cation : " Of this variety thousands go off every year. With 

 regard to the disease I observe, (1) in places where plants get 

 little or no sun, though they do not flower well, the rot never 

 comes ; (2) it attacks particular varieties, e.g. Ard Eigh,. 

 Spurius coronatus, and Golden Spur worse than others ; while 

 Horsefieldi, Emperor, and all of the muticus blood are entirely 

 exempt. The incomparabilis tribe never show a symptom of it, 

 however delicate their growth may be ; nor do any poeticus or 

 other delicate Narcissi, such as triandrus ; (3) the best pre- 

 ventive is annual transplanting. Maximus used to suffer here., 

 but by this means I now have a large and healthy stock of this 

 form." 



Baspberry Canes diseased. — Mr. G. Massee reported on the 

 plants sent to the last meeting from Holly Lodge, Highgate, as- 

 follows : " The black patches on the stems are caused by a. 

 minute parasitic fungus belonging to the genus Dothidea, pro- 

 bably D. rosa3, Fr., but as the specimens are immature the 

 species is not certain. Spiraea and other rosaceous plants suffer 

 from the attacks of species of Dothidea. In all known cases the 

 spores germinate at once when mature, and then infest the 

 younger shoots ; hence the entire removal of all diseased portions 

 before the spores are mature is imperative." 



Conifers, Growth of. — Photographs were received from Mr. 

 Curtis, of Kensington, showing the comparative growth of a 

 Silver Fir (Abies pectinata), and of a Douglas Fir (A. Douglasi), 

 which grew side by side for twenty-two years. The former was 

 10J inches in diameter, the latter 19^ inches. The trees were 

 taken from a plantation in Ireland, in a soil equally adapted to 

 both. The comparative results showed strongly in favour of the 

 cultivation of the Douglas Fir as a timber tree in Great Britain, 

 and Ireland. 



Odontoglossum citrosmum, Monstrous. — A blossom was 

 received from Mr. Bull, in which there were three well- 

 developed stamens and three lips, the two extra hps representing 

 two lateral stamens. 



