[Phoc. Koy. Soc. Victoria, 20 (X.S.), Pt. II., 1907.] 



Anr. X. — 2Vif Voi'inatlon of Red Wood in Conifers. 



By jean white, M.Sc. 

 [Read l-4th November, 1007]. 



A series of experiments was carried out by Professor Ewart 

 and Mr. Mason-Jones, on Pinus contorta, and P. cembra, and on 

 Cupressus nutkaensis and C. LaAvsoniana, in which certain of 

 the lateral branches were curved round and tied securely for 

 some time, until new wood could be formed. The results of their 

 experiments, published in the " Annals of Botany," April, 1906, 

 led them to conclude that in all probability the formation of 

 red wood was a " morphogenic response to a g^'avitational 

 stimulus." 



Professor Ewart suggested that I should carry the investiga- 

 tions further by noting the effects of diffusing the actiiui of 

 gravity, by causing a plaint to rotate on a klinostat. 



The plants experimented 'on were growing in flower pots, and 

 included Araucaria excelsa, Callitris Gunnii, Cedrus deodara, 

 Cr\'"ptomeria elegans, Cupressus sempervirens, Juniperub phoe- 

 nicea, Pinus strobus, Podocarpus elata, Sequoia sempervirens, 

 Taxus baccata. Thuja orientalis. 



On 20th September. 1906, the Cupressus was put on to the 

 klinostat, which was set rotating at the rate of one turn in 

 four hours. The remaining plants were laid down horizontally on 

 their sides, in a glas>-house, the upper .side of each pot being 

 marked. The plants had been in-evimisly tied to long stakes, 

 so as to relieve the pressure on the under side. 



The plants were all examined on 28th November, 1906. and 

 the following results were noted: — In Araucaria excelsa, Cryp- 

 tomeria elegans, Juniperus phoenicea, Pinus strobus, Podocarpus 

 ©lata. Sequoia sempervirens, and Taxus baccata, there was an 

 extremely well-marked layer of red wood developed on the under 

 side of the stem, as it lay horizontally. AI^o the red wood was 

 very conspicuous on the under surface of all the lateral branches 

 which were examined. -is 



