88-2 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



gonuni, Scutellaria, LalJiyrus, Potentilla, Bidcns, &c., forming a 

 dense growth 2 to 6 feet above the substratum. 



This border zone appears to be transitional to the Maple-Alder 

 society of large-sized Maples [Acer riihrum), Alders, Poison Sumach, 

 Prunus spp., Oaks, Ashes, and Silver Maple, the last three being rare. 

 The tree roots do not go more than 1 foot below the surface. 



The paper also contains the results of many careful researches as to 

 the growth of plants in peaty soil. Chemical analyses of peat samples 

 in the various zones and from other places are given. Only 8 to 

 12 per cent, of the nitrogen in peat seems available for plants. This 

 available nitrogen is considerably increased when the peat is composted 

 with the bacterial life from stable manure. 



The peat soil, when exposed, was found to extract oxygen from 

 the air with great rapidity, this reducing action being greatest in 

 the lowest levels and in the central zone. The excessive oxygen 

 avidity must be injurious to plants unless the latter also possess 

 oxidizing powers or mycorrhiza, &c. The maximum amount of reduc- 

 tion occurs in early autumn. 



The bacterial flora of the peat substratum was elaborately investi- 

 gated by culture on a large variety of media. Peat soils are found 

 to be very rich in bacteria, inducing diastatic, inverting, proteolytic, 

 cyto-hydrolytic, and reducing action, but the organisms vary in the 

 different substrata. Most thrive as saprophytes in the upper layers. 

 One set of bacteria often prepares a m-cdium for another out of an 

 unfavourable substratum. A certain proportion of bacteria in these 

 soils produces substances which are injurious to all but special peat- 

 plants. 



The climate is pre-eminently that of a deciduous forest, with 

 relatively high percentage of atmospheric humidity, and with rain or 

 144 to 138 days. The climate does not explain the dry-climate charac- 

 ters of some of the peat-plants. 



Eecords of air, water, and soil temperatures at various depths are 

 given. The air showed a range of 69. 5° 0. (max. 35° 0., min. — 24.5° 

 0.). The soil (1 foot depth) had a range of 27° (max. 27°, min. 0°). 

 The soil at 5 feet depth had a range of 22.1° (max. 26°, min 3.9° 0.). 

 The substratum temperatures are not specially favourable to the 

 preservation of bog types, and the central (xerophytic) zone is less 

 liable to extremes of temperature than the Maple-Alder zone. 



In the winter the minimum temperature of the peat substratum is 

 considerably higher than that of the air. The shoots in July and 

 August were in air at a temperature of 7° to 35° 0., whilst the 

 roots were at temperatures between 16° and 27° 0. 



The amount of evaporation was also carefully investigated. The 

 total evaporation from May 28 to August 14 being 1,349.2 c.c. on an 

 open lawn near the university, 933.8 in the Sphagnum-Cranberry zone, 

 and 690.8 in the Maple-Alder zone— that is as 100, 69.2, and 51.2. 

 The vapour blanket over the lake is more stationary in the relatively 

 forested Maple-Alder zone. 



